Oracle creates a primary key auto-increment table (SQL statement implementation) and trigger application

1. Create a table
Copy codeThe Code is as follows:
CreatetableTest_Increase (
Useridnumber (10) NOTNULLprimarykey,/* Primary Key, automatically added */
Usernamevarchar2 (20)
);

2. Create an automatic growth sequence
Copy codeThe Code is as follows:
CREATESEQUENCETestIncrease_Sequence
INCREMENTBY1 -- add a few
STARTWITH1 -- count from 1
NOMAXVALUE -- do not set the maximum value. Set the maximum value: maxvalue9999
NOCYCLE -- always accumulate without repeating
CACHE10;

3. Create a trigger
Copy codeThe Code is as follows:
CREATETRIGGERTest_IncreaseBEFORE
InsertONTest_IncreaseFOREACHROW/* checks whether each row is triggered */
Begin
SelectTestIncrease_Sequence.nextvalinto: New. useridfromdual;
End;
// * Exit sqlplus row editing */

4. Submit
Copy codeThe Code is as follows:
Commit;

5. Test
Insertinto
Copy codeThe Code is as follows:
Test_Increase (Username) values ('test ');