In an earlier post, we saw how Oracle’s UNDO works in very basic terms. REDO is another critical aspect that goes hand in hand with UNDO. Let us get the basics of REDO sorted out here. UNDO and REDO In its most basic sense UNDO is information saved to get back in case a ROLLBACK … Continue reading Oracle REDO – A Basic Explanation
Nasty data-related errors: If you are looking to resolve one of these types of errors, you are in the right place. Please keep reading. ORA-01400: cannot insert NULL into (string) ORA-01401: inserted value too large for column ORA-02290: check constraint (string.string) violated ORA-02291: integrity constraint (string.string) violated - parent key not found ORA-02292: integrity constraint … Continue reading Oracle – Find A Needle In The Hay Stack – How To Pinpoint Data Errors Like “ORA-12899: value too large for column”
Why is the APPEND hint so great? In a prior post, we extolled the virtues of the APPEND hint (AKA Direct Path Insert). It is a great option to use • UNDO usage is negligible. It is only generated for index maintenance and meta data changes. The keyword is index maintenance – indexes generate UNDO. … Continue reading Oracle – Is my APPEND Hint Being Ignored? How To Find Out?
The purpose of this tip is to introduce you to an seldom-used by very useful clause within the ORDER BY of a SQL statement – NULLS FIRST or NULLS LAST. Here is a situation that I ran into: I was looking into the Oracle 11g system view v$sql_plan_monitor to find out the top execution plan … Continue reading Oracle Tip – ORDER BY with NULLS LAST or NULLS FIRST
If you are primarily a SQL Server developer and you are moving to Oracle, this is one of the nastiest surprises in store for you. You are so used to rolling back everything including DDL in SQL Server transactions but in Oracle, DDL inside transactions act as COMMIT. Fear not though, there are a ton … Continue reading Oracle Gotcha For The SQL Server Developer – DDL’s COMMIT Transactions Implicitly!