SQL Primary Keys Using Auto Increment
Example
Many databases allow to make the primary key value automatically increment when a new key is added. This ensures that every key is different.
CREATE TABLE Employees (
Id int NOT NULL AUTO_INCREMENT,
PRIMARY KEY (Id)
);
CREATE TABLE Employees (
Id SERIAL PRIMARY KEY
);
CREATE TABLE Employees (
Id int NOT NULL IDENTITY,
PRIMARY KEY (Id)
);
CREATE TABLE Employees (
Id INTEGER PRIMARY KEY
);
