Creating a Random Redaction Policy

3.10 Creating a Random Redaction Policy

A random redaction policy presents redacted data as randomly generated values, such as Ukjsl32[[]]]s for the character data type.

3.10.1 Syntax for Creating a Random Redaction Policy

A random redaction policy presents the redacted data to the querying application user as randomly generated values, based on the column data type.

Be aware that LOB columns are not supported.

The DBMS_REDACT.ADD_POLICY fields for creating a random redaction policy are as follows:

DBMS_REDACT.ADD_POLICY (
   object_schema           IN VARCHAR2 := NULL, 
   object_name             IN VARCHAR2,
   column_name             IN VARCHAR2 := NULL,
   policy_name             IN VARCHAR2,
   function_type           IN BINARY_INTEGER := NULL,
   expression              IN VARCHAR2,
   enable                  IN BOOLEAN := TRUE);

In this specification:

object_schema, object_name, column_name, policy_name, expression, enable: See General Syntax of the DBMS_REDACT.ADD_POLICY Procedure.
function_type: Specifies the function used to set the type of redaction. Enter DBMS_REDACT.RANDOM.

If you omit the function_type parameter, then the default redaction function_type setting is DBMS_REDACT.FULL.

Remember that the data type of the column determines which function_type settings that you are permitted to use. See Comparison of Full, Partial, Regexp, Random, and Nullify Redaction Based on Data Types.

3.10.2 Example: Random Redaction Policy

You can use the DBMS_REDACT.ADD_POLICY PL/SQL procedure to create a random redaction policy.

Example 3-9 shows how to generate random values. Each time you run the SELECT statement, the output will be different.

Example 3-9 Randomly Redacted Data Redaction Values

BEGIN
 DBMS_REDACT.ADD_POLICY(
   object_schema   => 'mavis', 
   object_name     => 'cust_info', 
   column_name     => 'login_username',
   policy_name     => 'redact_cust_rand_username', 
   function_type   => DBMS_REDACT.RANDOM,
   expression      => 'SYS_CONTEXT(''USERENV'',''SESSION_USER'') = ''APP_USER''');
END;
/

Query and redacted result:

SELECT login_username FROM mavis.cust_info;

LOGIN_USERNAME
--------------
N[CG{\pTVcK
PL{opergHKV