PostgreSQL/Sequence/nextval
Версия от 13:45, 26 мая 2010; (обсуждение)
Using nextval function to get sequence next value
postgres=#
postgres=#
postgres=# CREATE SEQUENCE myseq MINVALUE 0;
CREATE SEQUENCE
postgres=#
postgres=# -- Using currval(?)
postgres=#
postgres=# SELECT currval("myseq");
ERROR: currval of sequence "myseq" is not yet defined in this session
postgres=#
postgres=#
postgres=# drop sequence myseq;
DROP SEQUENCE
postgres=#
postgres=# -- Setting a sequence value
postgres=# CREATE SEQUENCE myseq MINVALUE 0;
CREATE SEQUENCE
postgres=#
postgres=# SELECT setval("myseq", 1010);
setval
--------
1010
(1 row)
postgres=#
postgres=# SELECT nextval("myseq");
nextval
---------
1011
(1 row)
postgres=#
postgres=#
postgres=# SELECT setval("myseq", 1010, false);
setval
--------
1010
(1 row)
postgres=#
postgres=# SELECT nextval("myseq");
nextval
---------
1010
(1 row)
postgres=#
postgres=# drop sequence myseq;
DROP SEQUENCE
postgres=#