sqlite unique primary key

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sqlite unique primary key

A primary key also implies NOT NULL, but a unique index can be nullable. There can be only one primary key, but there can be multiple unique indexes. If there ... ,UNIQUE Constraint − Ensures that all values in a column are different. PRIMARY Key − Uniquely identifies each row/record in a database table. CHECK ... ,The primary key of the table: is a column or a group of columns that uniquely ... The email and phone are unique therefore you use the UNIQUE constraint for ... ,,sqlite> CREATE TABLE something ( column1, column2, value, PRIMARY KEY .... In another way, you can also make the two column primary key unique and the ... ,This tutorial shows you how to use SQLite PRIMARY KEY constraint to define the primary key for a table. ,Both single column and composite (multiple column) primary keys are supported. A set of SQL constraints for each table. SQLite supports UNIQUE, NOT NULL, ... ,In this tutorial, you will learn how to use the SQLite UNIQUE constraint to ensure all values in a column or a group of ... contact_id INTEGER PRIMARY KEY,. ,SQLite 约束约束是在表的数据列上强制执行的规则。 ... UNIQUE 约束:确保某列中的所有值是不同的。 ... PRIMARY Key 约束:唯一标识数据库表中的各行/记录。 ,This SQLite tutorial explains how to create, add, and drop unique constraints in SQLite ... What is the difference between a unique constraint and a primary key?

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sqlite unique primary key 相關參考資料
Primary key or Unique index? - Stack Overflow

A primary key also implies NOT NULL, but a unique index can be nullable. There can be only one primary key, but there can be multiple unique indexes. If there ...

https://stackoverflow.com

SQLite Constraints - Tutorialspoint

UNIQUE Constraint − Ensures that all values in a column are different. PRIMARY Key − Uniquely identifies each row/record in a database table. CHECK ...

https://www.tutorialspoint.com

SQLite Create Table with Examples - SQLite Tutorial

The primary key of the table: is a column or a group of columns that uniquely ... The email and phone are unique therefore you use the UNIQUE constraint for ...

http://www.sqlitetutorial.net

SQLite PRIMARY KEY - TutorialsPoint

https://www.tutorialspoint.com

Sqlite primary key on multiple columns - Stack Overflow

sqlite> CREATE TABLE something ( column1, column2, value, PRIMARY KEY .... In another way, you can also make the two column primary key unique and the ...

https://stackoverflow.com

SQLite Primary Key: The Ultimate Guide To Primary Key - SQLite Tutorial

This tutorial shows you how to use SQLite PRIMARY KEY constraint to define the primary key for a table.

http://www.sqlitetutorial.net

SQLite Query Language: CREATE TABLE

Both single column and composite (multiple column) primary keys are supported. A set of SQL constraints for each table. SQLite supports UNIQUE, NOT NULL, ...

https://www.sqlite.org

SQLite UNIQUE Constraint - SQLite Tutorial

In this tutorial, you will learn how to use the SQLite UNIQUE constraint to ensure all values in a column or a group of ... contact_id INTEGER PRIMARY KEY,.

http://www.sqlitetutorial.net

SQLite 约束| 菜鸟教程

SQLite 约束约束是在表的数据列上强制执行的规则。 ... UNIQUE 约束:确保某列中的所有值是不同的。 ... PRIMARY Key 约束:唯一标识数据库表中的各行/记录。

http://www.runoob.com

SQLite: Unique Constraints - TechOnTheNet

This SQLite tutorial explains how to create, add, and drop unique constraints in SQLite ... What is the difference between a unique constraint and a primary key?

https://www.techonthenet.com