Part 11 same sequence in multi tables
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1. Sequence numbers are generated independently of tables and can be used across multiple tables. Individual sequence numbers may appear to be skipped if the transaction that generated them is rolled back. 2. The document demonstrates creating a sequence named seq1 and using it to generate primary key values for inserting rows into two different tables, t1 and girija. The sequence numbers are incremented sequentially across both tables from 6 to 9.
Part 11 same sequence in multi tables
- 1. 1DR. GIRIJA NARASIMHAN Part 11 - same sequence in multi tables
- 2. 2 Sequence numbers are generated independently of tables, so the same sequence can be used for one or for multiple tables. It is possible that individual sequence numbers will appear to be skipped, because they were generated and used in a transaction that ultimately rolled back. Additionally, a single user may not realize that other users are drawing from the same sequence. create sequence seq1 START WITH 6 INCREMENT BY 1 NOCACHE maxvalue 9 minvalue 6 cycle;
- 3. 3DR. GIRIJA NARASIMHAN SQL> create sequence seq1 2 START WITH 6 3 INCREMENT BY 1 4 NOCACHE 5 maxvalue 9 6 minvalue 6 7 cycle; Sequence created. SQL> create table t1(tno number(5),tname varchar2(25)); Table created. SQL> create table girija(gno number(5), name varchar2(25)); Table created.
- 4. 4 DR. GIRIJA NARASIMHAN SQL> insert into t1 values(seq1.nextval,'flower'); 1 row created. SQL> select * from t1; TNO TNAME ---------- ------------------------- 8 flower SQL> insert into t1 values(seq1.nextval,'lotus'); 1 row created. SQL> select * from t1; TNO TNAME ---------- ------------------------- 8 flower 9 lotus SQL> insert into girija values(seq1.nextval,'mango'); 1 row created. SQL> select * from girija; GNO NAME ---------- ------------------------- 6 mango SQL> insert into girija values(seq1.nextval,'banna'); 1 row created. SQL> select * from girija; GNO NAME ---------- ------------------------- 6 mango 7 banna SQL> insert into t1 values(seq1.nextval, 'sunflower'); 1 row created. SQL> select * from t1; TNO TNAME ---------- ------------------------- 8 flower 9 lotus 8 sunflower