Oracle solves the primary key auto-increment Problem

Both SQL server and mysql can set the primary key auto-increment, while the oracle primary key does not have the auto-increment attribute, which can be achieved through the following two methods:
1. Create a sequence through a trigger
Create Sequence

Java code
Create sequence messageid minvalue 1 maxvalue start with 1 increment by 1 NOCACHE;

Create a trigger

Java code
Create or replace trigger ID_TRIGGER
Before insert on box for each row declare newId NUMBER (18, 0 );
Begin select messageid. nextval INTO newId FROM dual;: new. Id: = newId;
END;

2. Create a sequence using the id obtained by the sequence in an SQL statement.
Create Sequence

Java code
Create sequence messageid minvalue 1 maxvalue start with 1 increment by 1 NOCACHE;

Use in SQL statements
A. Obtain the id:
Java code
Select messageid. nextval FROM dual;

B. Direct use:
Java code
Insert into box (id, name) VALUES (MESSAGEID. nextval, "sa ")

Author "roc08"