PostgreSQL auto increment primary key creation method

In postresql, you only need to set the field type to serial.

For example

The code is as follows:

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Create table st_cat ( Id serial not null, Parentid integer,-parent id Catname character varying (20),-category name Memo character varying (500),-remarks Issub integer-whether subcategory exists ) WITH ( OIDS = FALSE ); Alter table st_cat Owner to IPVs; Comment on column st_cat.parentid IS 'parent ID '; Comment on column st_cat.catname IS 'Category name '; Comment on column st_cat.memo IS 'note '; Comment on column st_cat.issub IS 'has subcategory ';

It's strange to see similar code on the Internet.

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Nextval ('test _ a_id_seq ': regclass)

Where did this come from,

Later I found it in pgAdmin. It is in the corresponding table field and will appear

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Alter table test_a add column id integer; Alter table test_a alter column id set not null; Alter table test_a alter column id set default nextval ('test _ a_id_seq ': regclass );

Use the last one.

In this way, you can insert data as you like.

In Java code, sqlSession. commit (); operations are indispensable, otherwise the results will not be seen.

You can also use the oid field of each row as a unique value. However, if you need to dump or reload the database, you need to use the-o option of pg_dump or the copy with oids option to retain the OID.

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Insert into person values (nextval ('person _ id_req '), 'yourname ');