(Continued from previous part...)

77. What is a schema?

Answer1
The set of objects owned by user account is called the schema.

Answer2
Schema is the complete design of the database or data objects.

78. What are the options available to refresh snapshots?

COMPLETE - Tables are completely regenerated using the snapshots query and the master tables every time the snapshot referenced. FAST - If simple snapshot used then a snapshot log can be used to send the changes to the snapshot tables. FORCE - Default value. If possible it performs a FAST refresh; Otherwise it will perform a complete refresh.

79. What is a SNAPSHOT LOG?

A snapshot log is a table in the master database that is associated with the master table. ORACLE uses a snapshot log to track the rows that have been updated in the master table. Snapshot logs are used in updating the snapshots based on the master table.

80. What is Distributed database?

A distributed database is a network of databases managed by multiple database servers that appears to a user as single logical database. The data of all databases in the distributed database can be simultaneously accessed and modified.

81. What are the basic element of base configuration of an Oracle database?

It consists of
one or more data files.
one or more control files.
two or more redo log files.
The Database contains
multiple users/schemas
one or more rollback segments
one or more tablespaces
Data dictionary tables
User objects (table,indexes,views etc.,)
The server that access the database consists of
SGA (Database buffer, Dictionary Cache Buffers, Redo log buffers, Shared SQL pool)
SMON (System MONito)
PMON (Process MONitor)
LGWR (LoG Write)
DBWR (Data Base Write)
ARCH (ARCHiver)
CKPT (Check Point)
RECO
Dispatcher
User Process with associated PGS

82. What is a deadlock? Explain.

Two processes waiting to update the rows of a table, which are locked by other processes then deadlock arises.
In a database environment this will often happen because of not issuing the proper row lock commands. Poor design of front-end application may cause this situation and the performance of server will reduce drastically.
These locks will be released automatically when a commit/rollback operation performed or any one of this processes being killed externally.

83. What is Privilege Auditing?

Privilege auditing is the auditing of the use of powerful system privileges without regard to specifically named objects.

84. What is Object Auditing?

Object auditing is the auditing of accesses to specific schema objects without regard to user.

85. Physical DB Structure

ORACLE db consists of atleast one or more data files, two or more redo log files & one or more control files. The files of a db provide the actual physical storage for db info.

86. Logical DB Structure

ORACLE db consists of one or more tablespaces, the db schema??s objects (i.e. tables, views, indexes, clusters, sequences, sp). Tablespaces, Segments, Extents dictate how physical space of a db is used.

86. Tablespaces

A db is divided into logical storage units called TS. TS is used to group related logical structures together. Each db is logically divided into one or more TS. One or more data files are explicitly created for each TS to physically store the data of all logical structures in a TS. Combined size of the data file is the total storage capacity of TS. Combined storage capacity of the TS??s is the total storage capacity of the db.

(Continued on next part...)