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February 6, 2015

2/06/2015 04:26:00 PM

The Key words that are used in Oracle are :
 a) Commit: A transaction is said to be commit when the transaction makes permanent changes resulting from the SQL statements.

b)    Rollback      : A transaction that retracts any of the changes resulting from SQL statements in Transaction.

 c)  Save Point      : For long transactions that contain many SQL statements, intermediate markers or save points are declared. Save points can be used to divide a transaction into smaller points.

d)  Rolling Forward:: Process of applying  redo log during recovery is called rolling forward.

 e) Cursor: A cursor is a handle (name or a pointer) for the memory
associated with a specific statement.  A cursor is basically an area allocated by Oracle for executing the Sql Statement. Oracle uses an implicit cursor statement for Single row query and Uses Explicit cursor for a multi row query.

f) System Global Area (SGA) :: The SGA is a shared memory region allocated by the Oracle  that contains Data and control information for one Oracle Instance. It consists of Database  Buffer Cache and Redo log Buffer.

g) PGA :: The PGA is a memory buffer  that contains data and control  information for server process.

g) Database Buffer Cache:: Database Buffer of SGA stores the most recently used blocks  of database data. The set of database buffers in an instance is called Database Buffer Cache.

h) Redo log Buffer   : Redo log Buffer of SGA stores all the redo log entries.
i) Redo Log Files      : Redo log files are set of files that protect altered database data in memory that has not been written to Data Files. They are basically used for backup when a database crashes.

j) Process   : A Process is a 'thread of control' or mechanism in Operating System that executes series of steps.

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