![]() ![]() Note that MySQL requires an unique or primary key constraint on AUTO_INCREMENT columns. There is the table option AUTO_INCREMENT that allows you to define the start value, but you cannot define the increment, it is always 1: CREATE TABLE teams (id INT AUTO_INCREMENT UNIQUE, name VARCHAR (90)) AUTO_INCREMENT = 1 - start value. SEQUENCE is often used when we want to describe a unique key or primary key or column which is auto-incremented in database tables. ![]() In PostgreSQL, we have a special database object called a SEQUENCE object that is a list of ordered integer values. The following article provides an outline on PostgreSQL Auto Increment. PostgreSQL has the data types smallserial, serial and bigserial these are not true types, but merely a notational convenience for creating unique identifier columns.These are similar to AUTO_INCREMENT property supported by some other databases. If a primary key column (which is forced unique and non-null) is available, it can be depended on to provide a unique seed for the hash function. You should always be using a primary key on your table because postgresql internally uses hash table structures to increase the speed of inserts, deletes, updates and selects. ![]()
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