Author: Shoumadip Das

collection_column_datatype

Collection As Table Column Datatype

In PL/SQL,we can use both VARRAY & NESTED TABLE collection type as table column datatype. The difference between these implementation…

Database Locking

Understanding LOCKING In Database

CONCURRENT access is accessing same data by multiple users at the same time. • SHARED lock is acquired when user…

Understanding TRANSACTIONS In Database

What Is A Transaction ? Transaction is logically joining multiple SQL statements (unit of work) which we can either commit/rollback.In…

Oracle-collection-method

PL/SQL Collection Methods

WHAT IS COLLECTION ? A collection is a data structure that acts like a list or a single-dimensional array of…

Oracle-Flashback

Understanding FLASHBACK Technology

In Oracle database,under SGA there is an optional memory component known as – Flashback buffer.When Flashback Database is enabled, the…

Understanding-Invisible-Index

Understanding INVISIBLE Index

By default an index is VISIBLE.The Oracle optimizer will pick only VISIBLE index. Oracle 11g allows indexes to be marked…

Understanding UNUSABLE Index

By default an index is USABLE.The Oracle optimizer will pick only USABLE index. Oracle indexes can go into a UNUSABLE…