我如何在postgres中执行自动增量？(How do I enforce an auto increment in postgres?)

我如何在postgres中执行自动增量？(How do I enforce an auto increment in postgres?)

我可以通过设置序列并将表列默认值设置为该序列来创建自动增量，但我仍然可以手动输入一个不是该序列的值。 我如何在插入时对此执行约束？ 唯一使用触发器的方法是？

I can create an auto increment by setting a sequence and setting a tables column default value to be that sequence, but I can still manually enter a value that is not that sequence. How can I enforce a constraint to this on insert? Is using a trigger the only way?

最满意答案

这有帮助吗？

我测试过了，只要它的UNIQUE就可以插入主键。 如果它的Null自动序列踢入（ tablename_colname_seq ）并插入一个UNIQUE主键。

-- Table: test CREATE SEQUENCE tablename_colname_seq; CREATE TABLE foo( primary_id int not null UNIQUE default nextval('tablename_colname_seq'), a_nother int ) WITH ( OIDS=FALSE );

ALTER TABLE foo所有者postgres;

- 测试数据

insert into foo (primary_id) values(14) insert into foo (a_nother) values(13); select * from foo;

祝一切顺利

Does this help?

Ive tested this and you can insert the primary key as long as its UNIQUE. If its Null the auto sequence kicks in (tablename_colname_seq) and inserts a UNIQUE primary key.

-- Table: test CREATE SEQUENCE tablename_colname_seq; CREATE TABLE foo( primary_id int not null UNIQUE default nextval('tablename_colname_seq'), a_nother int ) WITH ( OIDS=FALSE );

ALTER TABLE foo OWNER TO postgres;

-- Test Data

insert into foo (primary_id) values(14) insert into foo (a_nother) values(13); select * from foo;

All the best