ALTER DATA MOVEMENT RULE¶

Replaces the MAX_ROWS expression of an existing data movement rule, sets or unsets its comment, or renames the rule.

Any changes to the rule take effect the next time a data movement policy that uses the rule is evaluated.

See also:

CREATE DATA MOVEMENT RULE , DROP DATA MOVEMENT RULE , SHOW DATA MOVEMENT RULES , DESCRIBE DATA MOVEMENT RULE

CREATE DATA MOVEMENT POLICY , ALTER DATA MOVEMENT POLICY , DROP DATA MOVEMENT POLICY

Syntax¶

ALTER DATA MOVEMENT RULE [ IF EXISTS ] <name>
  SET MAX_ROWS AS () RETURNS INTEGER
  -> ( <expression> )

ALTER DATA MOVEMENT RULE [ IF EXISTS ] <name> SET COMMENT = '<string_literal>'

ALTER DATA MOVEMENT RULE [ IF EXISTS ] <name> UNSET COMMENT

ALTER DATA MOVEMENT RULE [ IF EXISTS ] <name> RENAME TO <new_name>

Parameters¶

name

Specifies the identifier for the data movement rule to alter.

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.

RENAME TO new_name

Specifies the new identifier for the data movement rule; must be unique for your schema. The new identifier can’t be used if the identifier is already in place for a different data movement rule.

For more details, see Identifier requirements.

You can move the object to a different database and/or schema while optionally renaming the object. To do so, specify a qualified new_name value that includes the new database and/or schema name in the form db_name.schema_name.object_name or schema_name.object_name, respectively.

Note

• The destination database and/or schema must already exist. In addition, an object with the same name cannot already exist in the new location; otherwise, the statement returns an error.
• Moving an object to a managed access schema is prohibited unless the object owner (that is, the role that has the OWNERSHIP privilege on the object) also owns the target schema.

SET ...

Specifies one or more properties to set for the data movement rule:

MAX_ROWS AS () RETURNS INTEGER -> ( expression )

SQL expression body that returns an INTEGER, which sets the maximum number of rows that the movement type can move.

The return value determines the behavior:

• NULL - No limit on the number of rows.
• 0 - Block the movement.
• A positive integer - The maximum number of rows that the movement type can move.

The expression can contain CASE and other logic statements. It can call SYS_CONTEXT to read session and movement context and adjust the returned limit accordingly.

COMMENT = 'string_literal'

Adds a comment or overwrites the existing comment for the data movement rule.

Default: No value

UNSET ...

Specifies the property to unset for the data movement rule, which resets it to its default:

• COMMENT

To unset multiple properties or parameters with a single ALTER statement, separate each property or parameter with a comma.

When unsetting a property or parameter, specify only the property or parameter name (unless the syntax above indicates that you should specify the value). Specifying the value returns an error.

Access control requirements¶

Usage notes¶

• You can’t change the movement type of an existing data movement rule. To change the movement type, drop the rule and create a new one.

• GET_DDL is supported for this object type. If you want to see the current definition of the rule, run the GET_DDL function.

• Regarding metadata:

  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.

Examples¶

Lower the row limit on an existing rule:

ALTER DATA MOVEMENT RULE hr_pii_copy_limit
  SET MAX_ROWS AS () RETURNS INTEGER
  -> (500);

Rename a data movement rule:

ALTER DATA MOVEMENT RULE hr_pii_copy_limit RENAME TO hr_pii_export_limit;