【注意】consrc 在被引用的对象改变之后不会被更新,它不会跟踪字段的名字修改。与其依赖这个字段,最好还是使用 pg_get_constraintdef() 来抽取一个检查约束的定义。 【注意】pg_class.relchecks 需要和在此表上为给定关系找到的检查约束的数目一致。 pg_conversion pg_conversion 描述可用的编码转换信息。 pg_datab...
con.contypeasconstraint_type,CASEWHENcon.contype='p'THEN1-- primary key constraintWHENcon.contype='u'THEN2-- unique constraintWHENcon.contype='f'THEN3-- foreign key constraintWHENcon.contype='c'THEN4ELSE5ENDastype_rank, pg_get_constraintdef(con.oid)asconstraint_definitionFROMpg_catalog.pg_...
SELECT conname AS constraint_name, conrelid::regclass AS partition_table, pg_get_constraintdef(oid) AS constraint_definition FROM pg_constraint WHERE contype = 'p' AND conrelid IN ( SELECT inhrelid::regclass FROM pg_inherits WHERE inhparent = '表名'::regclass ); 例如,要查询 sales 表的...
在PostgreSQL中,可以使用以下SQL查询语句来列出所有表的所有约束: 代码语言:txt 复制 SELECT conname AS constraint_name, conrelid::regclass AS table_name, pg_get_constraintdef(c.oid) AS constraint_definition FROM pg_constraint c JOIN pg_namespace n ON n.oid = c.connamespace WHERE n.nspname =...
postgres=# select pg_get_viewdef(‘v1’); pg_get_viewdef SELECT + FROM t1; (1 row) postgres=# SELECT conname, pg_get_constraintdef(r.oid, true) as definition FROM pg_constraint r WHERE r.conrelid = ‘t1’::regclass; conname | definition ...
ALTERTABLEtable_nameADDCONSTRAINTconstraint_nameconstraint_definition;ALTERTABLEtable_nameDROPCONSTRAINTIFEXISTconstraint_name;ALTERTABLEtable_nameALTERCOLUMNcolumn_nameDROPNOTNULL; Example ALTER TABLE example ADD CONSTRAINT unique_constraint UNIQUE (a, c); ...
Which type of data a table can store that may be decided by the type of data. That is why CONSTRAINTS needed. Suppose the age of a student is always be a positive value but there is no such data type which can accept the only positive value, a CONSTRAINT can do this. ...
ROW_COUNT=0; 表的returning 取真正被操作的行的最终数据. 视图的returning 取最后一个instead of for each row触发器函数的返回值. FOUND和ROW_COUNT的用法如下 : There are several ways to determine the effect of a command. The first method is to use the GET DIAGNOSTICS command, which has the for...
(i = 0; i < ntuples; i++) { HeapTuple tuple; tuple = ExecFetchSlotHeapTuple(slots[i], true, NULL); slots[i]->tts_tableOid = RelationGetRelid(relation); tuple->t_tableOid = slots[i]->tts_tableOid; heaptuples[i] = heap_prepare_insert(relation, tuple, xid, cid, options);...
ALTERDOMAINname{SETDEFAULTexpression|DROPDEFAULT}ALTERDOMAINname{SET|DROP}NOTNULLALTERDOMAINnameADDdomain_constraintALTERDOMAINnameDROPCONSTRAINTconstraint_name[RESTRICT|CASCADE]ALTERDOMAINnameOWNERTOnew_owner 复制 ALTER FUNCTION 修改一个函数的定义。 ALTERFUNCTIONname([type[,...]])RENAMETOnew_nameALTERFUNCTION...