NAME
DROP CAST - 删除一个用户定义的类型转换
SYNOPSIS
DROP CAST (sourcetype AS targettype) [ CASCADE | RESTRICT ]
DESCRIPTION 描述
DROP CAST 删除一个前面定义的类型转换。
要能删除一个类型转换，你必须拥有源或者目的数据类型。 这是和创建一个类型转换相同的权限。
PARAMETERS 参数
- sourcetype
类型转换里的源数据类型。- targettype
类型转换里的目的数据类型。- CASCADE
- RESTRICT
这些键字没有任何效果，因为在类型转换上没有依赖关系。
EXAMPLES 例子
删除从 text 到 int 的转换：
DROP CAST (text AS int);
COMPATIBILITY 兼容性
DROP CAST 遵循 SQL 标准。
SEE ALSO 参见
CREATE CAST [create_cast(7)]
#p#
NAME
DROP CAST - remove a cast
SYNOPSIS
DROP CAST (sourcetype AS targettype) [ CASCADE | RESTRICT ]
DESCRIPTION
DROP CAST removes a previously defined cast.
To be able to drop a cast, you must own the source or the target data type. These are the same privileges that are required to create a cast.
PARAMETERS
- sourcetype
- The name of the source data type of the cast.
- targettype
- The name of the target data type of the cast.
- CASCADE
- RESTRICT
- These key words do not have any effect, since there are no dependencies on casts.
EXAMPLES
To drop the cast from type text to type int:
DROP CAST (text AS int);
COMPATIBILITY
The DROP CAST command conforms to the SQL standard.
SEE ALSO
CREATE CAST [create_cast(7)]
