一、回滚DDL

1. 回滚表的创建

postgres=# begin;

BEGIN

postgres=# create table test (id int, name text);

CREATE TABLE

postgres=# \dt

List of relations

Schema | Name | Type | Owner

--------+------+-------+----------

public | test | table | postgres

(1 row)

postgres=# rollback ;

ROLLBACK

postgres=# \dt

No relations found.

2. 回滚表结构的修改

postgres=# create table test (id int, name text);

CREATE TABLE

postgres=# begin ;

BEGIN

postgres=# alter table test add column score int;

ALTER TABLE

postgres=# \d test

Table "public.test"

Column | Type | Modifiers

--------+---------+-----------

id | integer |

name | text |

score | integer |

postgres=# rollback ;

ROLLBACK

postgres=# \d test

Table "public.test"

Column | Type | Modifiers

--------+---------+-----------

id | integer |

name | text |

3. 回滚表的删除

postgres=# begin;

BEGIN

postgres=# drop table test ;

DROP TABLE

postgres=# \dt

No relations found.

postgres=# rollback ;

ROLLBACK

postgres=# \dt

List of relations

Schema | Name | Type | Owner

--------+------+-------+----------

public | test | table | postgres

(1 row)

4. 回滚表的清空

postgres=# insert into test values (1, 'a');

INSERT 0 1

postgres=# select * from test ;

id | name

----+------

1 | a

(1 row)

postgres=# begin ;

BEGIN

postgres=# truncate test ;

TRUNCATE TABLE

postgres=# select * from test ;

id | name

----+------

(0 rows)

postgres=# rollback ;

ROLLBACK

postgres=# select * from test ;

id | name

----+------

1 | a

(1 row)

5. 回滚索引的创建

postgres=# begin ;

BEGIN

postgres=# create index on test (id);

CREATE INDEX

postgres=# \d test

Table "public.test"

Column | Type | Modifiers

--------+---------+-----------

id | integer |

name | text |

Indexes:

"test_id_idx" btree (id)

postgres=# rollback ;

ROLLBACK

postgres=# \d test

Table "public.test"

Column | Type | Modifiers

--------+---------+-----------

id | integer |

name | text |

6. 回滚索引的删除

postgres=# create index on test (id);

CREATE INDEX

postgres=# \d test

Table "public.test"

Column | Type | Modifiers

--------+---------+-----------

id | integer |

name | text |

Indexes:

"test_id_idx" btree (id)

postgres=# begin ;

BEGIN

postgres=# drop index test_id_idx ;

DROP INDEX

postgres=# \d test

Table "public.test"

Column | Type | Modifiers

--------+---------+-----------

id | integer |

name | text |

postgres=# rollback ;

ROLLBACK

postgres=# \d test

Table "public.test"

Column | Type | Modifiers

--------+---------+-----------

id | integer |

name | text |

Indexes:

"test_id_idx" btree (id)

注意如果索引的创建和删除加了CONCURRENTLY，则不能放在事务里

postgres=# drop index test_id_idx ;

DROP INDEX

postgres=# \d test

Table "public.test"

Column | Type | Modifiers

--------+---------+-----------

id | integer |

name | text |

postgres=# begin ;

BEGIN

postgres=# CREATE INDEX CONCURRENTLY ON test (id);

ERROR: CREATE INDEX CONCURRENTLY cannot run inside a transaction block

postgres=# rollback ;

ROLLBACK

postgres=# \d test

Table "public.test"

Column | Type | Modifiers

--------+---------+-----------

id | integer |

name | text |

二、回滚DML

1. 回滚insert

postgres=# select * from test ;

id | name

----+------

1 | a

(1 row)

postgres=# begin ;

BEGIN

postgres=# insert into test values (2, 'b');

INSERT 0 1

postgres=# select * from test ;

id | name

----+------

1 | a

2 | b

(2 rows)

postgres=# rollback ;

ROLLBACK

postgres=# select * from test ;

id | name

----+------

1 | a

(1 row)

2. 回滚update

postgres=# select * from test ;

id | name

----+------

1 | a

(1 row)

postgres=# begin ;

BEGIN

postgres=# update test set id = 2 where id = 1;

UPDATE 1

postgres=# select * from test ;

id | name

----+------

2 | a

(1 row)

postgres=# rollback ;

ROLLBACK

postgres=# select * from test ;

id | name

----+------

1 | a

(1 row)

3. 回滚delete

postgres=# select * from test ;

id | name

----+------

1 | a

(1 row)

postgres=# begin ;

BEGIN

postgres=# delete from test where id = 1;

DELETE 1

postgres=# select * from test ;

id | name

----+------

(0 rows)

postgres=# rollback ;

ROLLBACK

postgres=# select * from test ;

id | name

----+------

1 | a

(1 row)