Differences Between Auto-increment columns (IDS) in Oracle and Mysql

The auto-increment column here mainly refers to the auto-increment of the primary key id in a table. Unlike Mysql, Oracle cannot set the auto-increment column feature when creating a table in CREATE. Else l

The auto-increment column here mainly refers to the auto-increment of the primary key id in a table. Unlike Mysql, Oracle cannot set the auto-increment column feature when creating a table in CREATE. Else l

The auto-increment column here mainly refers to the auto-increment of the primary key id in a table.

Unlike Mysql, Oracle cannot set the auto-increment column feature when creating a table in CREATE.

Oracle must automatically add columns by creating sequence sequences.

First, you must create a sequence. (Of course, you must first create a table and add a primary key constraint. This column assumes the constraint name is test_sequence)

Create sequence test_sequence
[Increment by 1] -- growth step size
[Start with 1] -- Starting from a few times
[Maxvalue 100] -- maximum value of growth
[Nomaxvalue] -- no maximum value

[Cycle | nocycle]; -- cyclic growth/non-cyclic Growth

After sequence is defined, test_sequence.nextval and test_sequence.currval can be used in the insert statement.
Test_sequence.currval returns the value of the current sequence, but test_sequence.currval must be used after test_sequence.nextval is initialized for the first time.
Test_sequence.nextval increases the sequence Value and returns the added sequence value.

Then, you can alter the sequence to change the auto-increment mode.
Alter sequence test_sequence increment by 1.

You can also use drop to delete sequence sequences.
Drop sequence test_sequence;

Mysql is much simpler for Oracle, and can be set during table creation.

Create table (
Id int (10) auto_increment primary key
) Auto_increment = 1;

Auto_increment = 1 Set auto-increment columns to start from 1