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Help Center/ GaussDB(DWS)/ SQL Syntax Reference (8.1.3.x)/ DDL Syntax/ ALTER REDACTION POLICY

ALTER REDACTION POLICY

Updated on 2024-12-19 GMT+08:00

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Function

ALTER REDACTION POLICY modifies a data redaction policy applied to a specified table.

Precautions

Only the owner of the table to which the redaction policy is applied has the permission to modify the redaction policy.

Syntax

Modify the expression used for a redaction policy to take effect.

      
         ALTER REDACTION POLICY policy_name ON table_name WHEN (new_when_expression);

Enable or disable a redaction policy.

     
        ALTER REDACTION POLICY policy_name ON table_name ENABLE | DISABLE;

Rename a redaction policy.

     
        ALTER REDACTION POLICY policy_name ON table_name RENAME TO new_policy_name;

Add, modify, or delete a column on which the redaction policy is used.

     
        ALTER REDACTION POLICY policy_name ON table_name 
    action;

There are several clauses of action:

     
        ADD COLUMN column_name WITH function_name ( arguments )
  | MODIFY COLUMN column_name WITH function_name ( arguments )
  | DROP COLUMN column_name

Parameter Description

policy_name
Specifies the name of the redaction policy to be modified.
table_name
Specifies the name of the table to which the redaction policy is applied.
new_when_expression
Specifies the new expression used for the redaction policy to take effect.
ENABLE | DISABLE
Specifies whether to enable or disable the current redaction policy.
- ENABLE
  Enables the redaction policy that was previously disabled for the table.
- DISABLE
  Disables the redaction policy currently applied to the table.
new_policy_name
Specifies the new name of the redaction policy.
column_name
Specifies the name of the table column to which the redaction policy is applied.

To add a column, use a column name that has not been bound to any redaction functions.

To modify a column, use the name of an existing column.

To delete a column, use the name of an existing column.
function_name
Specifies the name of a redaction function.
arguments
Specifies the list of arguments of the redaction function.
- MASK_NONE: indicates that no masking is performed.
- MASK_FULL: indicates that all data is masked to a fixed value.
- MASK_PARTIAL: indicates that partial masking is performed based on the specified character type, numeric type, or time type.

Examples

Create a user named test_role and an example table named emp, and insert data into the table.

     
        CREATE ROLE test_role PASSWORD '{Password}';

    
       DROP TABLE IF EXISTS emp;
CREATE TABLE emp(id int, name varchar(20), salary NUMERIC(10,2));
INSERT INTO emp VALUES(1, 'July', 1230.10), (2, 'David', 999.99);

Define a masking policy mask_emp on the emp table that hides the salary column from the user test_role.

     
        CREATE REDACTION POLICY mask_emp ON emp WHEN(current_user = 'test_role') ADD COLUMN salary WITH mask_full(salary);

Modify the expression for a redaction policy to make it take effect for the specified role (If no user is specified, the redaction policy takes effect for the current user by default.):

    
       ALTER REDACTION POLICY mask_emp ON emp WHEN (pg_has_role(current_user, 'redact_role', 'member'));
ALTER REDACTION POLICY mask_emp ON emp WHEN (pg_has_role('redact_role', 'member'));

Modify the expression for the data redaction policy to make it take effect for all users.

    
       ALTER REDACTION POLICY mask_emp ON emp WHEN (1=1);

Disable the redaction policy.

    
       ALTER REDACTION POLICY mask_emp ON emp DISABLE;

Enable the redaction policy again.

    
       ALTER REDACTION POLICY mask_emp ON emp ENABLE;

Change the redaction policy name to mask_emp_new.

    
       ALTER REDACTION POLICY mask_emp ON emp RENAME TO mask_emp_new;

Add a column with the redaction policy used.

    
       ALTER REDACTION POLICY mask_emp_new ON emp ADD COLUMN name WITH mask_partial(name, '*', 1, length(name));

Modify the redaction policy for the name column. Use the MASK_FULL function to redact all data in the name column.

    
       ALTER REDACTION POLICY mask_emp_new ON emp MODIFY COLUMN name WITH mask_full(name);

Delete an existing column where the redaction policy is used.

    
       ALTER REDACTION POLICY mask_emp_new ON emp DROP COLUMN name;

Helpful Links

CREATE REDACTION POLICY, DROP REDACTION POLICY

Parent topic: DDL Syntax

Previous topic: ALTER LARGE OBJECT

Next topic: ALTER RESOURCE POOL

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