Delete unused records from oracle table - oracle

Question

DB version : 11.2.0.4
OS Solaris 5.10
REQUIREMENT : Delete unused records from table only after finding if the record is being accessed or not.
We have a table employee, which has 100,000 records, if anyone select a particular record/records from employee table then, the respective record's STATUS column should get updated to 'ACTIVE' value.
This is required for auditing purpose, 60 days later we will delete all the records from employee table whose STATUS column value is is NULL. how can this be achieved?
My understanding so far, correct me if I am wrong:
1) Trigger can't be used as there is no SELECT event, we only have UPDATE, INSERT, DELETE event.
2) Oracle FGA (Fine grain auditing) may not solve the purpose. or may be I am not aware, is it doable with FGA?
Table:
CREATE TABLE EMPLOYEE
(
EMPID NUMBER,
NAME VARCHAR2(20 BYTE),
SALARY NUMBER,
DEPART VARCHAR2(100 BYTE),
STATUS VARCHAR2(100 BYTE)
)
sample records:
EMPID NAME SALARY DEPART STATUS
---------- --------------- ---------- -------------------- ----------
101 ALFA 1000 IT
102 BETA 2000 CLERK
103 PETER 3000 FINANCE
104 JOHN 4000 IT
105 MESSI 5000 TECH
106 ROMEO 5000 TECH
107 TERI 5000 TECH
108 ROBERT 5000 TECH
Example:
If any one issue below statements
query 1: SELECT * from EMPLOYEE where name='MESSI';
the auditing should update the STATUS='ACTIVE' of empid=105
EMPID NAME SALARY DEPART STATUS
---------- --------------- ---------- -------------------- ----------
101 ALFA 1000 IT
102 BETA 2000 CLERK
103 PETER 3000 FINANCE
104 JOHN 4000 IT
105 MESSI 5000 TECH 'ACTIVE'
106 ROMEO 5000 TECH
107 TERI 5000 TECH
108 ROBERT 5000 TECH
query 2: SELECT * from EMPLOYEE where DEPART='TECH';
The auditing should update the STATUS='ACTIVE' for empid=105,106,107,108
EMPID NAME SALARY DEPART STATUS
---------- --------------- ---------- -------------------- ----------
101 ALFA 1000 IT
102 BETA 2000 CLERK
103 PETER 3000 FINANCE
104 JOHN 4000 IT
105 MESSI 5000 TECH 'ACTIVE'
106 ROMEO 5000 TECH 'ACTIVE'
107 TERI 5000 TECH 'ACTIVE'
108 ROBERT 5000 TECH 'ACTIVE'

Answer 1

The solution suggested by Oracle to achieve what to want is Known as ILM or Information Lifecycle Management.
It allows you to archive, delete, move or do specific actions depending on some criterias (Such as last access).
But be aware, it requires an additional license.
I have a suggestion :
Enable SELECT audit on the target table
Create an AFTER INSERT TRIGGER that will get the inserted line in DBA_AUDIT_TRAIL et extract SQL_TEXT if the OBJECT_NAME was your table (+others checks)
Inside this trigger, do some string operations to get the WHERE CONDITION & use it for update.

Answer 2

Sounds like an ambiguous requirement to me. What happens if one does select * or select count(*)? That under the specification would make all employee records used.
The view v$SQL would contain "all" SQL statements issued, you could always look in there (going through v$plan_table with the object). Then use those to reverse engineer if the record was touched.

Answer 3

You may try FGA ( fine-grained Audit ) using the DBMS_FGA Package. Try Running the code block below in your schema. If it executes successfully , check if audits are lodged periodically in the DBA_COMMON_AUDIT_TRAIL or DBA_AUDIT_STATEMENT table ( check documentation ) while running a select query. Schedule a program that runs periodically to check the audit table and update the status column accordingly. I have never tried anything like this, However!.
BEGIN
dbms_fga.Add_policy(object_schema => 'HR', object_name => 'EMPLOYEE',
policy_name => 'STATUS_UPDATE', audit_condition => 'SELECT',
audit_column => 'NAME ,DEPART', handler_schema => NULL,
handler_module => NULL,
ENABLE => TRUE);
END;
/