It drops the specified function only if that function exists and, in this way,, it avoids error. Let’s see how the DROP FUNCTION IF EXISTS statement works. How Does the Postgres Drop Function If Exists Work? The DROP FUNCTION IF EXISTS drops the specified function if it exists in the ...
在查询分析器中使用drop trigger 触发器名称来删除触发器。 也可以同时删除多个触发器:drop trigger 触发器名称,触发器名称...注意:触发器名称是不加引号的。在删除触发器之前可以先看一下触发器是否存在: if Exists(select name from sysobjects where name=触发器名称 and xtype='TR') 用企业管理器删除 在企业...
DROP TABLE IF EXISTS <table_name> case. If it does not exist,=20=20 PostgreSQL issues a NOTICE-level message (in the parallel case, REVOKE=20= =20 prints nothing, which is OK to me). But if it exists and the user who=20=20 wants to drop the table is not the owner or a super...
CREATETRIGGERtrigger_name{BEFORE|AFTER|INSTEADOF}{event[OR...]}ONtable_name[FOR[EACH]{ROW|STATEMENT}][WHEN(condition)]EXECUTEFUNCTIONtrigger_function; 其中,event 可以是 INSERT、UPDATE、DELETE 或者 TRUNCATE,UPDATE 支持特定字段(UPDATE OF col1, clo2)的更新操作;触发器可以在事件之前(BEFORE)或者之后(A...
assert (con:execute"drop table if exists players") assert (con:execute[[ CREATE TABLE players( name varchar(50), class varchar(50) ) ]]) list = { {name="NickGammon", class="mage",}, {name="DavidHaley", class="warrior",},
To drop or delete an IDENTITY column from a table, execute the ALTER TABLE statement with the DROP IDENTITY option/clause: ALTER TABLE tbl_name ALTER COLUMN col_name DROP IDENTITY [ IF EXISTS ]; Use the IF EXISTS option to check the presence of an IDENTITY column before dropping it from ...
'exists' alter table 表名 drop constraint 默认值名称 go alter table 表名 drop column 列名 go --- --判断要创建临时表是否存在...#Test') Is Not Null Begin print '存在' End Else Begin print '不存在' End --- -- 判断要创建的存储过程名是否存在...[存储过程名]') and OBJECTPROPERTY(id,...
其中,游标又分为显式游标和隐式游标,这里重点说明显式游标的用法。显示游标显示游标的处理四个PL/SQL步骤:1)定义游标:就是定义一个游标名,以及与其相对应的 SELECT 语句。格式:CURSOR cursor_name[(parameter[, parameter]…)] IS select_statement;游标参数只...
postgres=# \h drop table You'll get help on just that item: Command: DROP TABLE Description: remove a table Syntax: DROP TABLE [ IF EXISTS ] name [, ...] [ CASCADE | RESTRICT ] \l List databases What most people think of as a database (say, a list of customers) is actually ...
defsetUp(self):postgres =PostgresHook()withpostgres.get_conn()asconn:withconn.cursor()ascur:fortableinTABLES: cur.execute("DROP TABLE IF EXISTS {} CASCADE;".format(table)) cur.execute("CREATE TABLE {}(some_str varchar, some_num integer);".format(table)) ...