ALTER TYPE

Modifies the properties for an existing user-defined type.

See also:

CREATE TYPE , DESCRIBE TYPE , SHOW TYPES , DROP TYPE , UNDROP TYPE

语法

ALTER TYPE [ IF EXISTS ] <name> SET
  COMMENT = '<string_literal>'

ALTER TYPE [ IF EXISTS ] <name> UNSET COMMENT

参数

name

指定要更改的用户定义类型的标识符。

If the identifier contains spaces or special characters, the entire string must be enclosed in double quotes. Identifiers enclosed in double quotes are also case-sensitive.

For more information, see Identifier requirements.

SET ...

指定要为用户定义类型设置的属性：

COMMENT = 'string_literal'

为用户定义类型添加注释或覆盖现有注释。

UNSET ...

指定要为用户定义类型取消设置的属性，将其重置为默认值。

目前，唯一可以取消设置的属性是 COMMENT，它会移除用户定义类型的注释（如果存在）。

访问控制要求

A role used to execute this operation must have the following privileges at a minimum:

权限对象备注
OWNERSHIP用户定义的类型OWNERSHIP is a special privilege on an object that is automatically granted to the role that created the object, but can also be transferred using the [GRANT OWNERSHIP](/sql-reference/sql/grant-ownership) command to a different role by the owning role (or any role with the MANAGE GRANTS privilege).

Operating on an object in a schema requires at least one privilege on the parent database and at least one privilege on the parent schema.

For instructions on creating a custom role with a specified set of privileges, see Creating custom roles.

For general information about roles and privilege grants for performing SQL actions on securable objects, see Overview of Access Control.

使用说明

  • 关于元数据：

    Attention

    Customers should ensure that no personal data (other than for a User object), sensitive data, export-controlled data, or other regulated data is entered as metadata when using the Snowflake service. For more information, see Metadata fields in Snowflake.

示例

Add a comment to the age user-defined type:

ALTER TYPE age SET COMMENT = 'User-defined type for storing age values';

Remove the comment from the age user-defined type:

ALTER TYPE age UNSET COMMENT;