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Oracle SQL Tutorial 18 - How to Create Foreign Keys
 
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In this video we are going to be creating foreign keys. I highly recommend watching the previous video before you watch this one. Essentially, we are creating a very simple database for a system where we can create projects and add people to those projects. We started with the users table: --Delete the table if needed: --DROP TABLE users; CREATE TABLE users( user_id NUMBER, username VARCHAR2(50 CHAR) UNIQUE, CONSTRAINT users_pk PRIMARY KEY (user_id) ); Now we are going to create a table for projects with a column that is a foreign key to the username. We're going to want to make this match data types: CREATE TABLE projects( project_id NUMBER, project_name VARCHAR2(50 CHAR) UNIQUE, creator VARCHAR2(50 CHAR) ) Next, we need to add the column attributes we decided on last video: CREATE TABLE projects( project_id NUMBER, project_name VARCHAR2(50 CHAR) UNIQUE, creator VARCHAR2(50 CHAR) NOT NULL ) NOT NULL because we want every project to have a creator, but we are not labeling UNIQUE because that means we could only have a specific username once in the table. We want to allow a user to create multiple projects. We also need to add a primary key: CREATE TABLE projects( project_id NUMBER, project_name VARCHAR2(50 CHAR) UNIQUE, creator VARCHAR2(50 CHAR) NOT NULL, CONSTRAINT projects_pk PRIMARY KEY (username) ) Now, the question that remains is, how can I tell Oracle that I want the username to reference the username column of the other table? We have to make a foreign key constraint. As you've learned from the previous videos, there are about three ways to create constraints. You can do it inline at the column level, unnamed. You can do it at the column level, named, and you can do it at the Table level, named. Usually the table-level is preferred, but I will quickly remind you how to do all three again. CREATE TABLE projects( project_id NUMBER, project_name VARCHAR2(50 CHAR) UNIQUE, creator VARCHAR2(50 CHAR) NOT NULL REFERENCES users (username), CONSTRAINT projects_pk PRIMARY KEY (project_id) ) This works, but if we want to name it, we should do this: CREATE TABLE projects( project_id NUMBER, project_name VARCHAR2(50 CHAR) UNIQUE, creator VARCHAR2(50 CHAR) NOT NULL CONSTRAINT projects_users_fk REFERENCES users (username), CONSTRAINT projects_pk PRIMARY KEY (project_id) ) This works, but the preferred method is to do it at the table level: CREATE TABLE projects( project_id NUMBER, project_name VARCHAR2(50 CHAR) UNIQUE, creator VARCHAR2(50 CHAR) NOT NULL, CONSTRAINT projects_pk PRIMARY KEY (project_id), CONSTRAINT projects_users_fk FOREIGN KEY (creator) REFERENCES users (username) ) Great! So you've learned how to create a foreign key, now we can see it inside of Oracle SQL Developer. One important thing when it comes to foreign keys is what happens when have data in your database and you try to delete the parent row that a row in the child table references? In the next video we are going to configure that using ON DELETE. See you all then and if you enjoy this series, please do me a huge favor by liking the video and subscribing to my YouTube channel. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ HELP ME! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 18654 Caleb Curry
SQL tutorials 18: SQL Foreign Key Constraint
 
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SQL Tutorial 18: SQL foreign key constraint. Topic covered in this tutorial 1. Defining SQL foreign key using create table at column level 2. Defining SQL foreign key using create table at table level 1. Defining SQL foreign key using Alter Table statement Links Website article: http://www.rebellionrider.com/sql-foreign-key.htm Primary key tutorial: http://www.rebellionrider.com/sql-foreign-key.htm Create Table Tutorial: http://www.rebellionrider.com/sql-create-table.html Tool used in this tutorial is SQL Developer. This tutorial series is part of SQL expert exam certification training. if you are preparing for SQL certification you can use my tutorials. This SQL Tutorial is a part of free training. Copy Cloud referral link || Use this link to join copy cloud and get 20GB of free storage https://copy.com?r=j7eYO7 Contacts E-Mail [email protected] Twitter https://twitter.com/rebellionrider Instagram http://instagram.com/rebellionrider Facebook. https://www.facebook.com/imthebhardwaj Linkedin. http://in.linkedin.com/in/mannbhardwaj/ Thanks for linking, commenting, sharing and watching more of our videos This is Manish from RebellionRider.com Foreign key is an Input/output data constraint which is also known as referential integrity constraint. Foreign key represent a link or say a relationship between columns of tables. Similar to primary key constraint Foreign Key constraint is also of two types. Simple Foreign key constraint and Composite Foreign key constraint. Constraint which involves only one column in foreign key in child table and one column in reference key in parent table is called Simple Foreign Key. While the constraint which involves more than one column in foreign key in child table and more than one column in reference key in the parent table is called Composite Foreign Key.
Views: 98900 Manish Sharma
Oracle SQL Tutorial 19 - ON DELETE (SET NULL and CASCADE)
 
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Welcome everyone! Something you need to consider when you are creating foreign keys is what happens if you delete the parent? As a reminder, the parent is the row that has the value you are referencing in the row that has a foreign key. Why is this something important to consider? It's important because foreign keys need to protect us from two primary things, unacceptable INSERT statements, and unacceptable DELETE statements. Let's see what happens when we try to insert incorrect data into the table with the foreign key: INSERT INTO projects VALUES (1, 'Update website homepage', 'CalebCurry') The response tells us plainly that there is no such user in the users table. So this works correctly. Deleting data on the other hand works a bit differently because the database does not know what you want to do with the child row when you delete the parent from the parent table. By default, we will get an error message that prevents the parent from being deleted, but there are some other options. How do we configure this? This is where the ON DELETE statement comes in. We add the keywords ON DELETE right after the foreign key and then we can give it the option of CASCADE or SET NULL. CASCADE means that if we delete the parent, we are also going to delete the child. In our situation what that means is that if somebody creates a project in our project table and then that persons account gets deleted, all of the projects he owns will also be deleted. CASCADE: CREATE TABLE projects( project_id NUMBER, Project_name VARCHAR2(50 CHAR) UNIQUE, creator VARCHAR2(50 CHAR) NOT NULL, CONSTRAINT projects_pk PRIMARY KEY (project_id), CONSTRAINT projects_users_fk FOREIGN KEY (creator) REFERENCES users (username) ON DELETE CASCADE ) SET NULL will take the value in the child table and get rid of it. What you are left with is NULL. This means that we have an orphaned child. The first thought you might have is that it is a bad thing to have an orphaned child, but in databases that is not always so. In our application if we had it set to SET NULL, when a user account gets deleted the projects would remain in existence they would just lack a creator. This might be a good thing if you are concerned about the long term survival of a project, this might be the route you want to go. It ultimately depends on the application purpose. If you don't like CASCADE or SET NULL, you can leave the entire ON DELETE statement and just have Oracle throw an error when a parent is deleted. As for us, we are going to use ON DELETE CASCADE. We need to use this with extreme caution. If you are not careful, someday you will run a delete a row and that will cascade through you database deleting a bunch of stuff you didn't want to delete. Stuff happens, so make sure you back up your database every once in eternity. Now, in the last video we started with a database design that had three tables. We've only created two in this video. In the next video we are going to create the next one, which is a little special. Then we'll finish things up by adding some indexes. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Support me on Patreon! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 13123 Caleb Curry
Example on foreign key constraint and delete cascade
 
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Join discussion on http://www.techtud.com/video-illustration/following-table-has-two-attributes-and-c-where-primary-key-and-c-foreign-gate
Views: 7405 Techtud
SQL tutorials 20: On Delete Cascade Foreign Key By Manish Sharma (RebellionRider)
 
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Oracle Database 11g Tutorial 20: On delete cascade This tutorial will show you how to define foreign key with on delete cascade clause. Links Blog: http://www.rebellionrider.com/on-delete-cascade.htm SQL Tutorial 19 On delete set Null: http://www.rebellionrider.com/on-delete-cascade.htm SQL Tutorial 19 Foreign Key: http://youtu.be/0nbkBI5r3Gw Copy Cloud referral link || Use this link to join copy cloud and get 20GB of free storage https://copy.com?r=j7eYO7 Tool used in this tutorial is SQL Developer. This tutorial series is part of SQL expert exam certification training. if you are preparing for SQL certification you can use my tutorials. This SQL Tutorial is a part of free training. Contacts E-Mail [email protected] Twitter https://twitter.com/rebellionrider Instagram http://instagram.com/rebellionrider Facebook. https://www.facebook.com/imthebhardwaj Linkedin. http://in.linkedin.com/in/mannbhardwaj/ Thanks for liking, commenting, sharing and watching more of our videos This is Manish from RebellionRider.com
Views: 43929 Manish Sharma
Database - Foreign Keys Part 2 - Adding and Deleting Data
 
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This is part 2 of the video's on foreign keys. It shows how data must be added or deleted when considering foreign key constraints in a database.
ON DELETE CLAUSE OF FOREIGN KEY CONSTRAINT IN ORACLE SQL WITH EXAMPLE (CASCADE/SET NULL/NO ACTION)
 
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This is a free video tutorial explaining about the nonmandatory on delete clause in the foreign key constraint in Oracle SQL database, the video explains about how the on delete set null and on delete cascade works, how it can be implemented with easy to understand examples. We have also shown practical demonstration on creating the foreign key constraint, and then deleting the data from the parent table and observing the changes that take place in the child table.
Views: 1243 Kishan Mashru
Oracle SQL Tutorial 14 - Column-Level and Table-Level Constraints
 
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In the previous video we talked about adding constraints at the column-level. We made it nice and simple by only requiring a few keywords, but the problem we were having is that we could not assign a name to the constraint, which many people like to do so we can reference easily if we need to at a later time. To do this, it requires a little bit more typing, but it will give us extra flexibility and many consider it to be the higher quality approach to adding constraints. Let's go though a simple example. Let's say we have a users table with a user_id column that we want to make a primary key. We will create the table like this: CREATE TABLE( user_ id NUMBER PRIMARY KEY ) Instead of adding the PRIMARY KEY keywords after the data type, we add: CONSTRAINT user_pk PRIMARY KEY Now, we have assigned the name user_pk to this constraint. You can do the same with other constraints, such as UNIQUE. The syntax would be CONSTRAINT username_un UNIQUE. The other way to create constraints requires to put all of our constraints at the bottom of our table creation rather than inline with the column. This type of constraint is known as a table-level constraints. To make a column a primary key using table-level constraints, we add it to the CREATE TABLE command as if it is another row and use the CONSTRAINT keyword to tell Oracle that what is coming is a constraint, not a column in our table. CREATE TABLE users( user_id NUMBER, username VARCHAR2(50 CHAR), CONSTRAINT username_un UNIQUE (username), CONSTRAINT users_pk PRIMARY KEY (user_id) ) The primary differences here is that you have to put the column you are talking about in parenthesis after the PRIMARY KEY keyword. That's because it's at the end of the table and you need a way to tell it what column you are talking about. The option of putting it at the end of the table has the added benefit in this situation because if we needed to have a primary key that is the combination of multiple columns, we can do that by just adding the other column in the PRIMARY KEY parenthesis right after a comma. In summary, there are three ways to make constraints. The first is at the column level, unnamed. The second is at the column level, named. The third is at the table level, also named. In the next video we are going to create a named constraint in Oracle SQL Developer, so stay tuned and be sure to subscribe! ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Support me! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 13066 Caleb Curry
MySQL 17 - ON DELETE and ON UPDATE
 
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Now, what happens when you have successfully created a reference, and now you try deleting the parent? This is where the ON DELETE clause come in. This is essentially how we configure how strict a foreign key is. There are 3 options you can give for an ON DELETE: RESTRICT / NO ACTION Yes - In MySQL they are the same, but not all DBMS. CASCADE Yes SET NULL Yes Now the default is RESTRICT. This means that when you try to delete a parent row, MySQL is going to throw an error and not let you. Cascade means that if you delete the parent row, any rows that reference that parent will also be deleted. This is pretty dangerous and not often recommended. SET NULL will set the foreign key to be NULL. Now obviously, this is going to require that the foreign key is not labelled NOT NULL. In addition to the ON DELETE clause, there is the ON UPDATE clause. This one is a little less common because it configures what happens when a parent value changes. Obviously, when you are referencing a primary key, the ON UPDATE clause is nearly useless. That's because the primary key value is never supposed to change. If, on the other hand, we have a foreign key referencing a UNIQUE column that is not a primary key, it may change occasionally. So the only times you have to worry about the ON UPDATE clause is with foreign keys referencing UNIQUE columns that are not a primary key, and when you have natural keys that break the rules and actually do change at some point in time. The ON UPDATE clause has the same options as the ON DELETE clause and they all work the same way. Now, the last thing you need to know about foreign keys is that they must match the data type of the column you are referencing. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Support me! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 12625 Caleb Curry
SQL: Foreign Key Creation
 
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In this tutorial, you'll learn how to create a foreign key column ....
Views: 37867 radhikaravikumar
SQL Foreign Key Constraints
 
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Jamie King of Neumont University showing what are and how to add foreign key constraints.
Views: 51950 Jamie King
Could not drop object because it is referenced by a FOREIGN KEY constraint - SQL Server P74
 
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SQL Server / T-SQL Tutorial Scenario: You are working as SQL Server DBA or Developer, You need to drop a table from a database. When you execute drop table SchemaName.TableName statement, you get below error. Msg 3726, Level 16, State 1, Line 12 Could not drop object 'SchemaName.TableName' because it is referenced by a FOREIGN KEY constraint. Now we know that the table is referenced by Foreign Key Constraint. The problem is how to find which table has that Foreign Key Constraint that is referencing to this table. Link to scripts used in SQL Server / TSQL Tutorial Video http://www.techbrothersit.com/2016/04/could-not-drop-object-because-it-is.html Check out our website for Different SQL Server, MSBI tutorials and interview questions such as SQL Server Reporting Services(SSRS) Tutorial SQL Server Integration Services(SSIS) Tutorial SQL Server DBA Tutorial SQL Server / TSQL Tutorial ( Beginner to Advance) http://www.techbrothersit.com/
Views: 2205 TechBrothersIT
Oracle Database11g tutorials 14 : How to CREATE TABLE using sql developer and command prompt
 
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Oracle Database11g tutorials 14 How to Create table using command prompt and Create table using sql developer Blog Link http://bit.ly/1TkY4Oe Time Line 0:25 Introduction of Tables in Database 1:03 What is Create Table (Introduction of create table) 1:30 Syntax of Create Table 2:08 How to create table using Command Prompt 4:55 How to create table using SQL Developer Links for Oracle Database tutorials 4: database connectivity using SQL developer and command prompt http://youtu.be/wSqoXRlXDUU You can have indepth knowledge about SQL create table here http://www.rebellionrider.com/sql-create-table.html Tool used in this tutorial is command prompt. This tutorial series is part of SQL expert exam certification training. if you are preparing for SQL certification you can use my tutorials. This SQL Tutorial is a part of free training. Copy Cloud referral link || Use this link to join copy cloud and get 20GB of free storage https://copy.com?r=j7eYO7 Contacts E-Mail [email protected] Twitter https://twitter.com/rebellionrider Instagram http://instagram.com/rebellionrider Facebook. https://www.facebook.com/imthebhardwaj Linkedin. http://in.linkedin.com/in/mannbhardwaj/ Thanks for linking, commenting, sharing and watching more of our videos This is Manish from RebellionRider.com Today in this oracle database tutorial we will see How to CREATE A TABLE. if we have to define a table in layman language then we can say that Tables are just a collection of Rows and Columns but In RDBMS tables are database objects which help in organizing data into ROWS and COLUMNS. We can also say that SQL tables are kind of data structure which are used by database for efficient storage of data. To create a table in our database we use SQL CREATE TABLE command. SQL CREATE TABLE is a type of DATA DEFINITION LANGUAGE also known as DDL. To Create a table in your schema you will require CREATE TABLE system privilege. In our future videos we will see what are system and object privileges and how to grant them to a user. Today for this video we will be using Sample schema HR which already has all the necessary privileges. Ohk Let's see the syntax. CREATE TABLE table name ( column name1 Data-Type(size), column name2 Data-Type(size), ..... ); CREATE TABLE is an oracle reserved word or say an Oracle key word whereas There are 3 different ways of creating a table in Oracle database. Creating a table using Command Line Interface (CLI) in Oracle database For demonstrating how to create table in oracle database using CLI, I'll be using Command prompt. Thats how we create table using command prompt. you can check your table structure by DESCRIBE command for that just write DESC and your table name. Like this Another way of creating a table is by using Graphic user interface (GUI) in Oracle database To demonstrate how to create table using GUI we will use SQL developer. Lets open our SQL developer I am connected to HR schema if you do not know how to create a connection to database using SQL developer please watch my oracle database tutorial 4 that explains database connectivity using SQL developer and command prompt. Link for this video is in the description below. So lets create a table. Creating a table using SQL developer is very easy we do not have to fire any query here. Let's start First of all right click on your connection in which you want to create a table and choose schema browser. This will open a separate schema browser pane or you can expend your connection by clicking this + sign and then right click on table and choose New Table. However I prefer working with schema browser so let's skip to schema browser pane here from the first drop-down list you can choose connection name and in the second drop down list you can choose what database objects you want to work with we want to create a table thus I'll choose table and then click this arrow here and choose option for new table Ok we have created a table wizard first of all give a unique name to your table and add some column as well. For this, click the green plus button. Now we already have a column so give it some name. Also choose a datatype from the list and specify any size you can check this not null column if in case you want to make this a mandatory column you can also specify default value and constraint If you want to make this column a primary key you can click here In my future video i'll show you what are these constraints and different ways of applying them on a column in a table. for this video we will concentrate on create table only so when you are done with all your columns click ok Thats your table You can double click on your table here and can see its structure. Thats it
Views: 168613 Manish Sharma
Oracle SQL Tutorial 21 - How to Create / Drop Indexes
 
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In the last video, we wrote up the SQL to create three tables: CREATE TABLE users( user_id NUMBER, username VARCHAR2(50 CHAR) UNIQUE, CONSTRAINT users_pk PRIMARY KEY (user_id) ); CREATE TABLE projects( project_id NUMBER, Project_name VARCHAR2(50 CHAR) UNIQUE, creator VARCHAR2(50 CHAR) NOT NULL, CONSTRAINT projects_pk PRIMARY KEY (project_id), CONSTRAINT projects_users_fk FOREIGN KEY (creator) REFERENCES users (username) ON DELETE CASCADE ); CREATE TABLE project_users( project_id NUMBER NOT NULL REFERENCES projects (project_id) ON DELETE CASCADE, user_id NUMBER NOT NULL REFERENCES users (user_id) ON DELETE CASCADE, CONSTRAINT project_users_pk PRIMARY KEY (project_id, user_id) ); I'm going to increase the size of the users table a bit by adding a first and last name column. CREATE TABLE users( user_id NUMBER, username VARCHAR2(50 CHAR) UNIQUE, first_name VARCHAR2(50 CHAR), last_name VARCHAR2 (50 CHAR), CONSTRAINT users_pk PRIMARY KEY (user_id) ); But before we finish this design, we should consider indexing certain columns. What columns should we index? Well, as a reminder, the columns that are indexed by default are columns with the UNIQUE constraint, and those that are labeled as primary keys. Columns that are not indexed but often should be are those labeled as a foreign key. The column that jumps out the most to me is the creator column of the project table. It's the only foreign key that is not part of some index. Let's fix this by creating our first index. The way we do that is with the CREATE INDEX command. CREATE INDEX projects_creator_ix ON projects (creator) What naming convention are we following for the index? We are naming it by the table name, followed by an underscore, followed by the column, followed by an underscore, followed by an ix (for index). In this situation it does not apply, but if our foreign key column is labeled as UNIQUE, we can add the UNIQUE keyword like this: CREATE UNIQUE INDEX projects_creator_ix ON projects (creator) Now if you want to get rid of an INDEX, you can use this command: DROP INDEX projects_creator_ix Now, if we want to select data from the user table and the project table we can do that much faster. That's because the foreign key and column it references are both indexed and those are the columns we would do the join on. We will discuss how to do joins in a future video. So what are some potential problems with this database design? Overall, it is pretty good. With this design though we need to make sure there is no way for someone to update a user's username. In the next video we are going to discuss why. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Support me on Patreon! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 7533 Caleb Curry
Oracle SQL Tutorial 15 - How to Add Primary Key Constraints
 
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The goal of this video is to take the CREATE TABLE statement we have and walk through the different ways to create primary keys. This and foreign keys are the most common constraints, so we need to make sure that you have this one down. Once we have a more complex database design with multiple tables, we will learn the proper way to create foreign keys. For now, I am going to keep all of our constraints at the column level, unnamed. The only exception is the primary key, because that is what we are focusing on in this video. The first way to create the primary key is at the column level, unnamed. The primary key is very important because it what we use to distinguish rows from one another. Every table you create is going to need a primary key, and I suggest putting a lot of effort into making sure your keys are set up correctly and organized. --Delete the table if needed: DROP TABLE users; CREATE TABLE users( user_id NUMBER PRIMARY KEY, username VARCHAR2(50 CHAR) NOT NULL UNIQUE ) The next way is at the column level, but named: --Delete the table: DROP TABLE users; CREATE TABLE users( user_id NUMBER CONSTRAINT users_pk PRIMARY KEY, username VARCHAR2(50 CHAR)NOT NULL UNIQUE ) The general naming convention here is the table name followed by an underscore, followed by pk for primary key. Finally, the third way, which is at the table level, is the way we are going to create our primary key: --Delete the table: DROP TABLE users; CREATE TABLE users( user_id NUMBER, username VARCHAR2(50 CHAR) NOT NULL UNIQUE, CONSTRAINT users_pk PRIMARY KEY (user_id) ) Now, once you've created these constraints, you can use Oracle SQL Developer to find these constraints. Open your databases in the connections tab and find the table in the Tables folder. Double click your table and travel to the Constraints tab. You can tell here that the UNIQUE constraint still exists in this table, but it has a pretty disgusting name. It kind of wants to make me puke. Referencing that constraint in the future with that wacky name would be a burden. Engrave these three options in your head so that you can use any of them whenever you need and can read other peoples' code. Thank you for sticking with the series thus far. In the next video, we will be…doing something. See you then! :) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Support me on Patreon! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 12746 Caleb Curry
SQL tutorials 17: SQL Primary Key constraint,  Drop primary Key
 
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Blog link: http://www.rebellionrider.com/sql-primary-key.htm SQL tutorial on Primary key / SQL Primary key, In this tutorial you will learn about simple primary key, composute primary key, how to drop primary key. defining primary key using create table and alter table along with many other things. Tool used in this tutorial is SQL Developer. This tutorial series is part of SQL expert exam certification training. if you are preparing for SQL certification you can use my tutorials. This SQL Tutorial is a part of free training. Copy Cloud referral link || Use this link to join copy cloud and get 20GB of free storage https://copy.com?r=j7eYO7 Contacts E-Mail [email protected] Twitter https://twitter.com/rebellionrider Instagram http://instagram.com/rebellionrider Facebook. https://www.facebook.com/imthebhardwaj Linkedin. http://in.linkedin.com/in/mannbhardwaj/ Thanks for linking, commenting, sharing and watching more of our videos This is Manish from RebellionRider.com So Primary Key There are two types of Primary keys First is Simple primary Key: Primary key which Involves only one column and Second is Composite Primary Key: Primary Key which involves more than one column. We will start with Simple primary key. You can create Primary key either with Create Table statement of by using Alter table Statement. Let's define simple primary key using create table statements. With create table statement we can either define primary key at column level or at table level. We will start with defining Primary key at column level using create table statement. You just have to put keyword Primary key after data type and size of column while defining a column of a table. Here oracle server will create a primary key on product id with default constraint name which will be slightly difficult to understand. You can give your own name to your constraint which is also a good practice.
Views: 96853 Manish Sharma
Oracle - SQL - Foreign Key Constraint
 
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Oracle - SQL - Foreign Key Constraint Watch more Videos at https://www.tutorialspoint.com/videotutorials/index.htm Lecture By: Mr. Anadi Sharma, Tutorials Point India Private Limited.
Oracle SQL Tutorial 20 - How to Create Composite Primary Keys
 
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This video is going to be a tutorial on how to create composite and compound keys. The difference between a composite and compound key is that a composite key can consist of any columns while a compound key has to consist of columns that are all keys themselves. We will be working with a compound key because we are going to be using the an intermediary table that has two foreign keys. The combination of both of the keys have to be unique. First, if we have any other CREATE TABLE commands, we are going to comment those out. We will space out the CREATE TABLE to have each column on a line, then we will add constraints as needed. CREATE TABLE project_users( project_id, user_id ) Now, let's add the data types: CREATE TABLE project_users( project_id NUMBER, user_id NUMBER } Now, what about some column attributes? I'm going to make both of the columns NOT NULL because we always want the rows to have a user and a project: CREATE TABLE project_users( project_id NUMBER NOT NULL, user_id NUMBER NOT NULL } Now, let's add the foreign key constraints. Now, what do we name these? We are going to add a primary key that covers both of these columns, so I'm going to be a sinner and not give these constraints names: CREATE TABLE project_users( project_id NUMBER NOT NULL REFERENCES projects (project_id), user_id NUMBER NOT NULL REFFERENCES users (user_id) ) Now, the way we have it now is that if we delete a project in the project table, and there are any rows in the project_users table, it will throw an error and prevent deletion. I would prefer for it to also delete any project members. That would make sense because if you delete a project we want it to delete the associate between that project and certain users. The same goes for if we delete a user, we want their association with a certain project to be deleted. To do this, we need to add the ON DELETE command: CREATE TABLE project_users( project_id NUMBER NOT NULL REFERENCES projects (project_id) ON DELETE CASCADE, user_id NUMBER NOT NULL REFERENCES users (user_id) ON DELETE CASCADE, ) Finally, let's learn how to create a compound or composite key. literally, the only difference is that you put a comma and add the second table inside of the parenthesis. CREATE TABLE project_users( project_id NUMBER NOT NULL REFERENCES projects (project_id) ON DELETE CASCADE, user_id NUMBER NOT NULL REFERENCES users (user_id) ON DELETE CASCADE, CONSTRAINT project_users_pk PRIMARY KEY (project_id, user_id) ) Now, the combination of project_id and user_id cannot be null, is always unique, and has an index. The only thing we should do now is add a few indexes. We aren't done yet...In the next video we are going to figure out what columns would benefit from indexes and we'll add them to it. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ HELP ME! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 9395 Caleb Curry
SQL in Oracle 11g Tutorial #7: Alter table( Add, Delete , Enable and Disable Primary Key)
 
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SQL in Oracle 11g Tutorial #7: Alter table( Add, Delete , Enable and Disable Primary Key). This video will explain you the following: 1. How to Add the Primary Key 2. How to delete the primary Key 3. How to Enable the Primary Key 4. How to disable the primary key Thanks for Watching my Channel “Learn TechToTech”. Please subscribe my channel for getting first updates after uploading video.Social Media pages of Channel are: 1. My Website : www.learnfromrakesh.com 2. My Twitter: https://twitter.com/LearnTechtotech 3. Facebook Page: https://www.facebook.com/LearnTechToTech 4. Blogger : https://learntechtotech.blogspot.in/ 5. Google+ : https://learntechtotech.blogspot.in/ 6. Pinterest : https://in.pinterest.com/LearnTechToTech/ 7. LinkedIn: https://www.linkedin.com/in/Learntechtotech/ Playlist of Different Technology: 1. Operating System : https://goo.gl/q6SfrW 2. Python Programming Language : https://goo.gl/L8b5dc 3. C Language : https://goo.gl/SwvDu9 4. C language for Placement: https://goo.gl/AaQBa4 5. Java: https://goo.gl/M8F2uy 6. MySql : https://goo.gl/vdJbHQ 7. Android Mobile Application Development: https://goo.gl/M6woaT 8. Kotlin Programming Language : https://goo.gl/GXE5cd 9. Go Programming: https://goo.gl/Ua3xYW 10. Internet of Things(IoT): https://goo.gl/f2afkY 11. Oracle 11g : https://goo.gl/zds8r2 12. C++ : https://goo.gl/C1psMT
Views: 298 Learn TechToTech
Oracle Foreign key Constraint تعليم اوراكل
 
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by Mohamed El Desouki - محمد الدسوقى [email protected] Tel :00966 553450836 جامعة سلمان بن عبد العزيز - السعودية - الخرج How To Combine two tables using Foreign Key Constraint.ربط الجداول بإستخدام قيد Text Book: Fundamentals of Database Systems, 5th Edition, by Elmasri/Navathe, published by Addison-W oracle create table statement oracle drop table statement oracle constraints database constraints primary key constraint foreign key constraint check constraint null not null constraint unique constraint
Learn MySQL In Arabic #18 - Constraint - Foreign Key Update, Delete
 
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Learn Foreign Key Options OnUpdate and OnDelete Cascade | Restrict | Set Null | No Action
Views: 10105 Elzero Web School
FOREIGN KEY CONSTAINT IN ORACLE SQL
 
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This is a free video tutorial explaining about foreign key constraint in Oracle SQL database, the video explains about how the foreign key works, how it can be implemented with easy to understand examples. We have also shown practical demonstration on creating the foreign key constraint, and then encountering the part not found, and child record exists kind of integrity constraint.
Views: 511 Kishan Mashru
Create, Alter, Drop foreign Key constraint in SQL Server - Part 14
 
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Subscribe to IT PORT : https://www.youtube.com/c/itport28 SQL Server Tutorial in Tamil : https://www.youtube.com/playlist?list=PLouAaeZ4xQ64enJDwWVvN3KduuZRlUrb3 SQL Server Concepts in Tamil : https://www.youtube.com/playlist?list=PLouAaeZ4xQ67kdNIByJKAGBIBhor_h4Hs SQL Server Analytic Functions in Tamil : https://www.youtube.com/playlist?list=PLouAaeZ4xQ65XIU5azEUgLVrBKEl-jWMV SQL Server Tutorial : https://www.youtube.com/playlist?list=PLouAaeZ4xQ66AYrzPtxt2SeeR4UABcBcO SQL Server Concepts : https://www.youtube.com/playlist?list=PLouAaeZ4xQ66zRe8-nDDy-YHY2o0rmbn4 SQL Server Analytic Functions : https://www.youtube.com/playlist?list=PLouAaeZ4xQ64hTsEdhLsVBquE1vERWngX A foreign key (FK) is a column or combination of columns that is used to establish and enforce a link between the data in two tables. You can create a foreign key by defining a FOREIGN KEY constraint when you create or modify a table. In a foreign key reference, a link is created between two tables when the column or columns that hold the primary key value for one table are referenced by the column or columns in another table. This column becomes a foreign key in the second table. A table can have 253 foreign key constraints.
Views: 164 IT Port
How to Create Table with Foreign Key Constraint in SQL Server - SQL Server / TSQL Tutorial Part 66
 
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SQL Server / TSQL Tutorial Scenario: What is Foreign Key in SQL Server Table: Foreign Key in a table is a column or group of columns that provides a link between data in two tables. The Foreign Key in a table points to the primary key in another table. In this video you will learn how to create foreign key constraint. Link to scripts used in SQL Server / TSQL Tutorial Video http://www.techbrothersit.com/2016/04/how-to-create-table-with-foreign-key.html Check out our website for Different SQL Server, MSBI tutorials and interview questions such as SQL Server Reporting Services(SSRS) Tutorial SQL Server Integration Services(SSIS) Tutorial SQL Server DBA Tutorial SQL Server / TSQL Tutorial ( Beginner to Advance) http://www.techbrothersit.com/
Views: 2131 TechBrothersIT
Oracle Drop, Disable and Enable Constraints تعليم اوراكل
 
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by Mohamed El Desouki - محمد الدسوقى [email protected] Tel :00966 553450836 جامعة سلمان بن عبد العزيز - السعودية - الخرج How to Drop , Disable and Enable Constraints. كيف حذف و تعطيل و إعادة تشغيل القيود Text Book: Fundamentals of Database Systems, 5th Edition, by Elmasri/Navathe, published by Addison-W oracle create table statement oracle drop table statement oracle constraints database constraints primary key constraint foreign key constraint check constraint null not null constraint unique constraint
How to Delete Table in sql using oracle 10g or sql
 
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This video gives information about How to Delete Table in sql using oracleXE 10g
Views: 2789 AvilTwo Beginer
phpMyAdmin tutorial: Setting up a foreign key constraint | lynda.com
 
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In a relational database such as MySQL, foreign keys are used to link records in different tables. Additionally, you can set up foreign key constraints to control what happens when records are inserted, updated, or deleted. Find out how to build foreign key constraints in this tutorial. Watch more at http://www.lynda.com/phpMyAdmin-tutorials/Up-Running-phpMyAdmin/144202-2.html?utm_campaign=A42FG4LzdbY&utm_medium=viral&utm_source=youtube. This tutorial is a single movie from the Up and Running with phpMyAdmin course by lynda.com author David Powers. The complete course is 2 hours and 33 minutes and shows how to administer MySQL databases, design tables, and insert, update, and delete data with phpMyAdmin. Introduction 1. Why Use phpMyAdmin? 2. Setting Up phpMyAdmin Locally 3. Creating Tables 4. Importing and Exporting Data 5. Dealing with Foreign Keys 6. Running Queries 7. Checking Performance Conclusion
Views: 229851 LinkedIn Learning
Creating Primary and Foreign Keys in SQL Server 2012
 
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Dr. Soper shows how to create simple and composite primary keys and foreign key relationships in a SQL Server database using SQL Server Management Studio. Several different methods of creating keys and establishing relationships between tables are demonstrated.
Views: 395230 Dr. Daniel Soper
Oracle SQL Tutorial 13 - How to Add Column Constraints (Attributes)
 
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So far, we have this table declaration: CREATE TABLE users( user_id NUMBER, username VARCHAR(50 CHAR) first_name VARCHAR2(50 CHAR), last_name VARCHAR2(50 CHAR) ) We can run this command see that it works. As we are learning though, we are going to want to be able to recreate our table with different settings and such, but if you try to run this command, it will complain that the table already exists. So we first need to delete this table before we start editing settings. When we get more experienced, we will learn about ways to edit the structure of a table that already exists. To fix this, we can get rid of the table using the DROP TABLE command: DROP TABLE users You can run this every time if you need to practice by adding a semicolon after it. This is how you can tell Oracle that you are putting in another command after it. This is known as a delimiter. When you run the script, it is going to run both commands. Now we can go through and reconsider our table structure. This is fine for starting out because we don't have any important data in our database, but once your database is in production you are not going to want to just drop tables. In the last video we discussed different constraints that you can apply to columns in a database table, but how do you actually apply these when you are creating a table? The first way you define constraints is to put them right after the column in your CREATE TABLE statement. CREATE TABLE users( username VARCHAR2(50 CHAR) NOT NULL ) When we define constraints this way, we usually say we are adding column attributes. If you have two constraints you want to add, you just put one after the other with spaces in between. There is no particular order that is required. CREATE TABLE users( username VARCHAR2(50 CHAR) NOT NULL UNIQUE ) In this situation we have already given the column the NOT NULL and UNIQUE attributes, so we should consider making this a primary key: CREATE TABLE users( username VARCHAR2(50 CHAR) PRIMARY KEY ) As you can see, adding column attributes is super easy. We can add a default like this: CREATE TABLE users( username VARCHAR2(50 CHAR) PRIMARY KEY, account_balance NUMBER DEFAULT 0 ) Note that now we need the comma after the first row. There are a few constraints we did not talk go through an example, specifically foreign keys and check constraints. We will be adding these constraints to our database in future videos. In the mean time, I have a thought for you… Many people prefer to name their column constraints. That way, we can refer to certain constraints by name. For example, we might have a primary key constraint that could be named users_pk. The way we are creating these constraints does not allow for this feature, so in the next video we are going to be discussing different ways to create constraints. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Support me on Patreon! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 17545 Caleb Curry
Oracle SQL Tutorial 16 - Parent Child Relationships
 
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So far in this series we have discussed database design, creating tables, and constraints. We've brought up the concept of foreign keys, but we have not explained how to create them. That is the goal of this video and the upcoming videos. We want to study those foreign keys! Let's make them not so foreign. Let's learn the proper way to define a foreign key. As a reminder, a foreign key is a column that references a column of another table. The column it references must either be a primary key, or have the UNIQUE constraint. This means that every value inside of the column that is labeled as a foreign key, there must be that value in some row of the referenced column. As an example, imagine that we have the users table, and we have a table service_requests. We could have a column in the service_request that references a column in the users table. Usually this would be the primary key that is referenced, but there is nothing stopping you from referencing a unique column. Just for fun, let's go through an example using the username column. If we have a service_requests table, every single row within the table is going to be what some would consider an instance of a service_request. This means that the table columns are like the blueprint for what a service request looks like and then each row is an individual service request. If we have one of the columns labeled as a foreign key to the username of the users table, what does that mean practically? It means that for a single row, the value for that column must be a value that exists in the users table. We could have a service_request submitted by a user with the username of Yoloswagman. This means that there must be a row inside of the users table that has the value Yoloswagman for the username column. This brings up the concept of parent and child relationships. Yoloswagman in this situation is the parent, and his service request is the child. When we draw it out, it makes sense why a primary key must be UNIQUE. If we had two Yoloswagmans, the child would not know which column is the parent. The same applies if we were using IDs and we had So remember, always reference a primary key or a column with the UNIQUE constraint. Now, I have a question for you. Do foreign keys automatically have the UNIQUE constraint, just like primary keys? The answer is no. A parent row can have many child rows. It makes sense because the user could submit multiple service requests. Can we force the column to be unique? Absolutely. If that was the case, the user could only make one service request. Another question. Do foreign keys automatically have the NOT NULL constraint, just like primary keys? The answer is no. Essentially what this means is that a child could be created with no parent. Can we force the column to be NOT NULL? Absolutely. It is ok in some situations to allow the row to be null, but in this situation it makes no sense. It would be wise for us to add that constraint ourselves. So now that you understand some more differences between primary and foreign keys and parent child relationships, take all of these questions into consideration when you are creating foreign keys. In the next video, we are going to start a small project that is going to require multiple tables. We'll take a video to design our structure and then we'll get to creating those foreign keys in Oracle SQL Developer. Stick around and if you like these videos please be a serious supporter and subscribe to my channel. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ HELP ME! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 10747 Caleb Curry
Create, Alter, Drop foreign Key constraint in SQL Server - Part 14 Tamil
 
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Subscribe to IT PORT : https://www.youtube.com/c/itport28 SQL Server Tutorial in Tamil : https://www.youtube.com/playlist?list=PLouAaeZ4xQ64enJDwWVvN3KduuZRlUrb3 SQL Server Concepts in Tamil : https://www.youtube.com/playlist?list=PLouAaeZ4xQ67kdNIByJKAGBIBhor_h4Hs SQL Server Analytic Functions in Tamil : https://www.youtube.com/playlist?list=PLouAaeZ4xQ65XIU5azEUgLVrBKEl-jWMV SQL Server Tutorial : https://www.youtube.com/playlist?list=PLouAaeZ4xQ66AYrzPtxt2SeeR4UABcBcO SQL Server Concepts : https://www.youtube.com/playlist?list=PLouAaeZ4xQ66zRe8-nDDy-YHY2o0rmbn4 SQL Server Analytic Functions : https://www.youtube.com/playlist?list=PLouAaeZ4xQ64hTsEdhLsVBquE1vERWngX A foreign key (FK) is a column or combination of columns that is used to establish and enforce a link between the data in two tables. You can create a foreign key by defining a FOREIGN KEY constraint when you create or modify a table. In a foreign key reference, a link is created between two tables when the column or columns that hold the primary key value for one table are referenced by the column or columns in another table. This column becomes a foreign key in the second table. A table can have 253 foreign key constraints. Explained in Tamil
Views: 671 IT Port
Oracle SQL Tutorial 11 - CREATE TABLE
 
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The way you create a table is to use the CREATE TABLE command. CREATE TABLE users() So in this situation, the name comes right after the TABLE keyword. The next thing we do is put all of the columns on a line that we want to put in our table. CREATE TABLE users( user_id, username, first_name, last_name ) Notice the naming conventions here. For this series we are going to make columns with what is known as snake casing. This is where each individual word is separated by an underscore. if you have more than one column, all of them have to have commas except the last one. The comma is a way to say that another column is coming, so you don't need to do it on the last one. Now you would think we were done, but we also have to say what data type each column is. Later we will extensively discuss data types so we can focus on them exclusively. For now, here are the data types we are going to use: CREATE TABLE users( user_id NUMBER, username VARCHAR2(50), first_name VARCHAR2(50), last_name VARCHAR2(50) ) Now, inside of the parenthesis for varchar2, we pass in a number... This is the max length of the string. But the question is, what is it measured in? The default is actually in bytes, not characters. For example if we have the string hello, it is 5 characters, but it might take up a total of 10 bytes of storage. So I would recommend adding the keyword char right after the number so it defaults to 50 characters, not bytes. CREATE TABLE users( user_id NUMBER, username VARCHAR(50 CHAR), first_name VARCHAR2(50 CHAR), last_name VARCHAR2(50 CHAR) ) This will work to create a table, but it's really missing a lot of information… which column is the primary key? Are we adding any indexes? Is there any thing else we need to say about these columns? So as you can tell, we are making progress, but there is still so much to learn. The biggest gotcha to remember from this video is that the data type VARCHAR ends in a 2, stupid, right? who would end the name of something with a 2? Once again, this is Caleb from CalebTheVideoMaker2, and we will catch you in the next one! ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ HELP ME! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 28025 Caleb Curry
How to Create Foreign Key Constraint with ON DELETE SET NULL Option in SQL Server -SQL Server P81
 
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SQL Server / T-SQL Tutorial Scenario: You are working as SQL Server developer, you need to create two tables with Primary -Foreign Key Relationship. You want to create Foreign Key Constraint with setting if record will be deleted from Referenced Table (Primary Key Column Table), it should not be deleted from Parent Table ( Foreign Key Constraint Table) instead the value should be updated to Null. Link to scripts used in SQL Server / TSQL Tutorial Video http://www.techbrothersit.com/2016/04/how-to-create-foreign-key-constraint_95.html Check out our website for Different SQL Server, MSBI tutorials and interview questions such as SQL Server Reporting Services(SSRS) Tutorial SQL Server Integration Services(SSIS) Tutorial SQL Server DBA Tutorial SQL Server / TSQL Tutorial ( Beginner to Advance) http://www.techbrothersit.com/
Views: 851 TechBrothersIT
How to disable all Foreign Key Constraint in SQL Server Database-SQL Server / TSQL Tutorial Part 77
 
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SQL Server / T-SQL Tutorial Scenario: You are working as SQL Server developer, You need to provide the scripts to disable all the Foreign Key Constraint in SQL Server database. This might be scenario where you need to load one time data and you are ok if data violate referential integrity. Link to scripts used in SQL Server / T-SQL Tutorial Video http://www.techbrothersit.com/2016/04/how-to-disable-all-foreign-key.html Check out our website for Different SQL Server, MSBI tutorials and interview questions such as SQL Server Reporting Services(SSRS) Tutorial SQL Server Integration Services(SSIS) Tutorial SQL Server DBA Tutorial SQL Server / TSQL Tutorial ( Beginner to Advance) http://www.techbrothersit.com/
Views: 1366 TechBrothersIT
SQL with Oracle 10g XE - Using ALTER TABLE to ADD and DROP Table Columns
 
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In this video I use the ALTER TABLE command to add and delete a new field column from a table. I used the keywords ADD or DROP to make the changes to the table design. The commands I used were: ALTER TABLE BOOKS ADD SAMPLE VARCHAR(10); ALTER TABLE BOOKS DROP COLUMN SAMPLE; This video is part of a series of videos with the purpose of learning the SQL language. For more information visit Lecture Snippets at http://lecturesnippets.com.
Views: 8784 Lecture Snippets
106. Create Table with Foreign Key in SQL Practical (Hindi)
 
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Please Subscribe Channel Like, Share and Comment Visit : www.geekyshows.com
Views: 17677 Geeky Shows
CREATE TABLE WITH CONSTRAINTS - ORACLE - SQL
 
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Create table , add constraints : primary key constraint, foreign key constraint, check constraint, unique constraint, specifying the table space for index, modifying table, dropping table Oracle 10g
Views: 9806 R.N.A. Creation
How to create Foreign Key Constraint with ON DELETE CASCADE in SQL Server - SQL Server Tutorial 80
 
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SQL Server / T-SQL Tutorial Scenario: You are working as SQL Server developer, you need to create two tables with Primary -Foreign Key Relationship. You want to create Foreign Key Constraint with setting if record will be deleted from Referenced Table (Primary Key Column Table), it should be deleted from Parent Table ( Foreign Key Constraint Table) as well. Link to scripts used in SQL Server / TSQL Tutorial Video http://www.techbrothersit.com/2016/04/how-to-create-foreign-key-constraint_29.html Check out our website for Different SQL Server, MSBI tutorials and interview questions such as SQL Server Reporting Services(SSRS) Tutorial SQL Server Integration Services(SSIS) Tutorial SQL Server DBA Tutorial SQL Server / TSQL Tutorial ( Beginner to Advance) http://www.techbrothersit.com/
Views: 2828 TechBrothersIT
SQL Server 27 - How to Create FOREIGN KEY Constraints
 
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In the previous video we set up an entire table. The problem with this table is that the species column is just plain text. The problem with this is that there is a higher probability of incorrect data and if we have tons of animals in here there will be a lot of redundant information. The solution to this is to change this species to a foreign key to another table. Remember that when you create a foreign key it is a child to a parent. The thing you need to know is that the parent has to exist before the child so the child has something to reference. So let's create the parent table. CREATE TABLE Species( ID INT PRIMARY KEY IDENTITY, Species VARCHAR(50) NOT NULL UNIQUE, FriendlyName VARCHAR(50) NOT NULL //NOT UNIQUE because multiple rows could be same category (Ex: Bunny) ); Now, the friendly name will likely have redundant data, so maybe later we can add a table for animal categories or something, but let's not overwhelm ourselves quite yet. Maybe in a few videos. Now that we have created that table, we can recreate the table that references it. The first thing to know when creating a foreign key is that the data type must match. Because the ID column in the species table is of type INT, we should make our Species column in the Animals table also of type INT. Secondly, to make this a foreign key we add REFERENCES Species(ID) to the Species column. DROP TABLE IF EXISTS Animals; CREATE TABLE Animals( ID INT PRIMARY KEY IDENTITY, Name VARCHAR(50) NOT NULL, Species INT NOT NULL REFERENCES Species(ID), ContactEmail VARCHAR(50) NOT NULL UNIQUE ); ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Support me! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 3618 Caleb Curry
Foreign Key in Oracle
 
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Foreign Key in Oracle oracle foreign key WHAT IS A FOREIGN KEY IN ORACLE? 1)A foreign key is a use to make referential integrity in database. 2)Foreign key values in one table must also appear in another table also. 3)The referenced table is called the parent table. 4)Table with the foreign key is called the child table. 5)The foreign key generally reference a primary key in the parent table. CREATE TABLE DEPT --- parent table ( DEPT_ID NUMERIC(10) NOT NULL, EMP_ID NUMERIC(10) NOT NULL, CONSTRAINT DEP_PK PRIMARY KEY (DEPT_ID) ); CREATE TABLE EMPLOYEE -- child table ( EMP_ID NUMERIC(10) NOT NULL, NAME VARCHAR2(50) NOT NULL, CITY VARCHAR2(50), DEPT_NO NUMERIC(10), CONSTRAINT ID_PK PRIMARY KEY (EMP_ID), CONSTRAINT FK_DEP FOREIGN KEY (DEPT_NO) REFERENCES DEPT(DEPT_ID) ); #techquerypond https://techquerypond.wordpress.com https://twitter.com/techquerypond
Views: 410 Tech Query Pond
SQL tutorial 19: ON DELETE SET NULL clause of Foreign Key By Manish Sharma (RebellionRider)
 
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SQL Tutorial 19 : ON DELETE SET NULL foreign key Clause. Links used in the tutorial On delete set null website article [ download SQL script from same link] : http://www.rebellionrider.com/on-delete-set-null.htm Foreign Key Tutorial Video : http://youtu.be/0nbkBI5r3Gw Foreign Key Tutorial Blog : http://www.rebellionrider.com/sql-foreign-key.htm This video is the part of foreign key video In this sql tutorial you will learn the referential clause ON DELETE SET NULL of foreign key. On Delete Set null clause guarantee the relation integrity in foreign key/ Tool used in this tutorial is SQL Developer. This tutorial series is part of SQL expert exam certification training. if you are preparing for SQL certification you can use my tutorials. This SQL Tutorial is a part of free training. Copy Cloud referral link || Use this link to join copy cloud and get 20GB of free storage https://copy.com?r=j7eYO7 Contacts E-Mail [email protected] Twitter https://twitter.com/rebellionrider Instagram http://instagram.com/rebellionrider Facebook. https://www.facebook.com/imthebhardwaj Linkedin. http://in.linkedin.com/in/mannbhardwaj/ Thanks for liking, commenting, sharing and watching more of our videos This is Manish from RebellionRider.com
Views: 47080 Manish Sharma
Oracle Insert Into Statement تعليم اوراكل
 
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by Mohamed El Desouki - محمد الدسوقى [email protected] Tel :00966 553450836 جامعة سلمان بن عبد العزيز - السعودية - الخرج How to Insert new data in a table. كيف تدخل بيانات جديدة فى الجدول Text Book: Fundamentals of Database Systems, 5th Edition, by Elmasri/Navathe, published by Addison-W oracle create table statement oracle drop table statement oracle constraints database constraints primary key constraint foreign key constraint check constraint null not null constraint unique constraint insert into statement update statement delete statement
Oracle SQL Tutorial For Beginners | Oracle SQL Online Training - Session 1
 
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Course : Oracle SQL Online Training Mode of Training : Online Duration : 40 Hours Timings : Flexible Oracle SQL Online Training Demo Registration Link : http://svsoftsolutions.com/demo.aspx Introduction to SQL What is SQL? What Can SQL do? RDBMS SQL Syntax Database Tables SQL Statements Overview of Most Important SQL Commands SELECT UPDATE DELETE INSERT CREATE TABLE ALTER TABLE DROP TABLE CREATE INDEX DROP INDEX SQL SELECT Statement SELECT syntax Demo Database SELECT Column Example SELECT * Example SQL Distinct SELECT DISTINCT Statement SELECT DISTINCT Syntax SELECT DISTINCT Example SQL WHERE Clause WHERE Clause WHERE Clause Example Operators in the WHERE Clause SQL AND & OR Operators AND Operator Example OR Operator Example Combining AND & OR SQL ORDER BY ORDER BY Syntax ORDER BY Example ORDER BY DESC Example ORDER BY Several Column Examples SQL Insert Into INSERT INTO Syntax INSERT INTO Examples Insert Data into Specified Columns SQL UPDATE UPDATE Syntax UPDATE Example Watch out UPDATE statement. SQL DELETE DELETE Syntax DELETE Examples Delete All the Data SQL Aliases SQL Alias Syntax for Columns Alias Example for Table Columns Alias Example for Tables. SQL Joins Different SQL JOINs INNER JOIN LEFT OUTER JOIN RIGHT OUTER JOIN FULL OUTER JOIN SQL UNION UNION Syntax UNION Example UNION ALL Syntax UNION ALL Example SQL Insert Into Select INSERT INTO SELECT Syntax INSERT INTO SELECT Examples SQL Create Table CREATE TABLE Syntax CREATE TABLE Example SQL Constraints CREATE TABLE + CONSTRAINT Syntax NOT NULL Constraint UNIQUE Constraint UNIQUE Constraint on CREATE TABLE UNIQUE Constraint on ALTER TABLE To DROP a UNIQUE Constraint PRIMARY KEY Constraint PRIMARY KEY Constraint on CREATE TABLE PRIMARY KEY Constraint on ALTER TABLE To DROP a PRIMARY KEY Constraint FOREIGN KEY Constraint FOREIGN KEY Constraint on CREATE TABLE FOREIGN KEY Constraint on ALTER TABLE To DROP a FOREIGN KEY Constraint CHECK Constraint CHECK Constraint on CREATE TABLE CHECK Constraint on ALTER TABLE To DROP a CHECK Constraint DEFAULT Constraint on CREATE TABLE DEFAULT Constraint on ALTER TABLE To DROP a DEFAULT Constraint SQL Create Index CREATE INDEX Syntax CREATE UNIQUE INDEX Syntax CREATE INDEX Example SQL DROP Command The DROP INDEX Statement The DROP TABLE Statement The DROP DATABASE Statement The TRUNCATE TABLE Statement SQL ALTER Command The ALTER TABLE Statement ALTER TABLE Example Change Data Type Example DROP COLUMN Example SQL VIEWS CREATE VIEW Statement CREATE VIEW Syntax CREATE VIEW Examples CREATE OR REPLACE VIEW Syntax Dropping a View SQL NULL Values Working with NULL Values IS NULL IS NOT NULL SQL NULL Functions NVL COALESCE For more details visit our website : www.svsoftsolutions.com Or reach us @ USA : +1-845-915-8712 (Toll Free), India : +91-9642373173
Views: 799 SV Soft Solutions
Oracle Tutorials : 5 - CREATE / DROP TABLE
 
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Oracle Tutorials : 5 - CREATE / DROP TABLE
Views: 954 Meganadha Reddy
SQL Tutorial - Create Table with Constraints
 
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This video tutorial will show you how to create a table with constraints in Microsoft SQL Server. The video covers, data types of columns, NOT NULL constraints, PRIMARY KEY constraints, FOREIGN KEY constraints, CHECK constraints and DEFAULT constraints. Data types enforce limits to the what can inserted in to tables and constraints further build on this, for example if you wanted to add a column called age, the values will usually range from 0 - 100 so we could choose a data type of TINYINT which allows values of up to 255 but this means if you enter 255 this is still a valid age. We want to control this even further so we can add a CHECK constraint that will only allow values from 0 - 100. Check out the video for how to add this constraint. CREATE TABLE dbo.[Login] ( Username VARCHAR(30) NOT NULL CONSTRAINT PK_Login_Username PRIMARY KEY (Username) , [Password] VARCHAR(30) NOT NULL , LastUpdate DATETIME2 NOT NULL CONSTRAINT DF_Login_LastUpdate DEFAULT (CURRENT_TIMESTAMP) , [Status] CHAR(10) NOT NULL CONSTRAINT CK_Login_Status CHECK ([Status] IN ('Active', 'Inactive')) , CustomerID INT CONSTRAINT FK_Login_CustomerId FOREIGN KEY (CustomerId) REFERENCES Customers (CustomerId) )
Views: 647 BeardedDev
SQL in Oracle 11g Tutorial #9: Implementation/Example of Primary Key and Foreign Key
 
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SQL in Oracle 11g Tutorial #9: Implementation/Example of Primary Key and Foreign Key. How to create a Primary Key. How to create a Foreign Key. Thanks for Watching my Channel “Learn TechToTech”. Please subscribe my channel for getting first updates after uploading video.Social Media pages of Channel are: 1. My Website : www.learnfromrakesh.com 2. My Twitter: https://twitter.com/LearnTechtotech 3. Facebook Page: https://www.facebook.com/LearnTechToTech 4. Blogger : https://learntechtotech.blogspot.in/ 5. Google+ : https://learntechtotech.blogspot.in/ 6. Pinterest : https://in.pinterest.com/LearnTechToTech/ 7. LinkedIn: https://www.linkedin.com/in/Learntechtotech/ Playlist of Different Technology: 1. Operating System : https://goo.gl/q6SfrW 2. Python Programming Language : https://goo.gl/L8b5dc 3. C Language : https://goo.gl/SwvDu9 4. C language for Placement: https://goo.gl/AaQBa4 5. Java: https://goo.gl/M8F2uy 6. MySql : https://goo.gl/vdJbHQ 7. Android Mobile Application Development: https://goo.gl/M6woaT 8. Kotlin Programming Language : https://goo.gl/GXE5cd 9. Go Programming: https://goo.gl/Ua3xYW 10. Internet of Things(IoT): https://goo.gl/f2afkY 11. Oracle 11g : https://goo.gl/zds8r2 12. C++ : https://goo.gl/C1psMT
Views: 87 Learn TechToTech
SQL Tutorial - 9: Create Table Statement
 
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In this tutorial we'll learn to create tables in SQL using the CREATE TABLE Statement.
Views: 284065 The Bad Tutorials
Create a Foreign Key in SparxSystems EA
 
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Create a foreign key on two tables in SparxSystems EA
Views: 1791 Bekwam, Inc

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