PostgreSQL 不允许这样做,因为存在来自vw_tover的依赖t: > ALTER TABLE t ALTER COLUMN t TYPE char(10); ERROR: cannot alter type of a column used by a view or rule DETAIL: rule _RETURN on view vw_t depends on column "t" > ALTER TABLE t ALTER COLUMN pk TYPE bigint; ERROR: cannot al...
ALTER [ COLUMN ] column_name ADD GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( sequence_options ) ] ALTER [ COLUMN ] column_name {SETGENERATED { ALWAYS | BY DEFAULT } |SETsequence_option | RESTART [ [ WITH ] restart ] } [...] ALTER [ COLUMN ] column_name DROP IDENTITY [ ...
11. 查询对象大小,在文档9.26系统管理函数中有介绍 12. 索引无效,PostgreSQL里没找到类似Oracle的alter index的语法设置索引,也没搜到类似Oracle的dba_indexes的status状态查看。PostgreSQL关于索引重建部分有索引INVALID查看方法;这个上篇中通过psql -E显示具体查询命令的,但太多,现在还分不清哪个是查询索引无效的。 如果...
CREATE TABLE rtable(c1 INT, c2 VARCHAR(10)) PARTITION BY RANGE(c1); ALTER TABLE rtable ADD CONSTRAINT pk_rtable PRIMARY KEY(c1); \d rtable Table "public.rtable" Column | Type | Collation | Nullable | Default ---+---+---+---+--- c1 | integer | | not null | c2 | charact...
ALTER [ COLUMN ] column_name SET DEFAULT expression highgo=# alter table p1 alter COLUMN pswd type text ;ALTER TABLE highgo=# \d p1 Table "public.p1"Column | Type | Collation | Nullable | Default ---+---+---+---+--- id | integer | | | pswd | text | ...
alter table userlist enable row level security ; 使用账号user01连接数据库 \c - user01 You are now connected to database "memfire" as user "user01". 执行查询操作,得到结果如下: select * from userlist id | name ---+--- 1 | user01 (1 row) 开启行级权限后,user01仅能够查询name...
(2,100) i;INSERT099postgres=# analyze t;ANALYZEpostgres=#createindex iont(b);CREATEINDEXpostgres=# \d tTable"public.t"Column|Type|Collation|Nullable|Default---+---+---+---+---a | integer | | |b | text | | |Indexes:"i" btree (b) postgres=# select relpages,reltuples from p...
ALTERTABLE[IFEXISTS]nameDETACH PARTITIONpartition_name [CONCURRENTLY| FINALIZE ] 大表search IN ( consts ) 优化 场景: SaaS业务, 电商, 社交等场景 业务特点:IN的输入条件很多导致IN过滤慢 价值: 支持 linear search TO hash table probe,提高IN语句的处理性能, 在条件多、被过滤掉的数据量大的SQL中性能提升...
postgres=#ALTERTABLEmytableALTERCOLUMNlarge_columnSETSTORAGEMAIN;ALTERTABLEpostgres=# \d+mytable Table"public.mytable"Column|Type|Collation|Nullable|Default|Storage---+---+---+---+---+---id|integer||notnull|nextval('mytable_id_seq'::regclass)|plain large_column|bytea|||mainIndexes:"myta...
postgres=# create index idx_test_id on test(id); CREATE INDEX postgres=# \d test Table "public.test" Column | Type | Collation | Nullable | Default ---+---+---+---+--- id | integer | | | name | text | | | Indexes: "idx_test_id" btree (id) postgres=# explain analyze...