How Oracle writes a trigger and serial number __oracle

The following code can be implemented with the Pl\sql tool, and the following is how an Oracle sets automatic sequence growth

--Create a table


CreateTable Book (

BookID varchar2 (4) PrimaryKey,

Name VARCHAR2 (20)

);


--Create a sequence


Create sequence book_seq start with 1 increment by 1;



--Creating triggers


Create or Replacetrigger Book_trigger


Before Inserton Book


For each row


Begin


Select Book_seq.nextval into:new.bookId from dual;


End;


--Add data


Insertinto book (name) VALUES (' cc ');


Insertinto book (name) VALUES (' DD ');