ORA-14551: cannot perform a DML operation inside a query

I got ” ORA-14551: cannot perform a DML operation inside a query ”  error in Oracle database.

ORA-14551: cannot perform a DML operation inside a query

Details of error are as follows.

ORA-14551 cannot perform a DML operation inside a query

Cause: DML operation like insert, update, delete or select-for-update cannot be performed 
inside a query or under a PDML slave.

Action: Ensure that the offending DML operation is not performed or use an autonomous
 transaction to perform the DML operation within the query or PDML slave.

cannot perform a DML operation inside a query

This ORA-14551 error is related with the DML operation like insert, update, delete or select-for-update cannot be performed inside a query or under a PDML slave.

Ensure that the offending DML operation is not performed or use an autonomous transaction to perform the DML operation within the query or PDML slave.

You should use the PRAGMA AUTONOMOUS_TRANSACTION;

You should give commit explicitly inside the function;

OR if you got this error when you run function as follows.

SQL> select testfunction('test') from dual;

Then run it as follows.

SQL> var myvar NUMBER;
SQL> call testfunction('test') into :myvar;  

Call completed.

Do you want to learn Oracle Database for Beginners, then read the following articles.

Oracle Tutorial | Oracle Database Tutorials for Beginners ( Junior Oracle DBA )