Database short questions part 5 | Gpgc mardan
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76. What is database Trigger?
A database trigger is a PL/SQL block that can defined to automatically execute for insert, update, and
delete statements against a table. The trigger can e defined to execute once for the entire statement
or once for every row that is inserted, updated, or deleted. For any one table, there are twelve events
for which you can define database triggers. A database trigger can call database procedures that are
also written in PL/SQL.
77. What are stored-procedures? And what are the advantages of using them?
Stored procedures are database objects that perform a user defined operation. A stored procedure
can have a set of compound SQL statements. A stored procedure executes the SQL commands and
returns the result to the client. Stored procedures are used to reduce network traffic.
78. What is Storage Manager?
It is a program module that provides the interface between the low-level data stored in
database, application programs and queries submitted to the system.
Also read:-
Database short questions part 1.
79. What is Buffer Manager?
It is a program module, which is responsible for fetching data from disk storage into main memory
and deciding what data to be cache in memory.
80. What is Transaction Manager?
It is a program module, which ensures that database, remains in a consistent state despite system
failures and concurrent transaction execution proceeds without conflicting.
81. What is File Manager?
It is a program module, which manages the allocation of space on disk storage and data
structure used to represent information stored on a disk.
82. What is Authorization and Integrity manager?
It is the program module, which tests for the satisfaction of integrity constraint and checks
the authority of user to access data.
83. What are stand-alone procedures?
Procedures that are not part of a package are known as stand-alone because they independently
defined. A good example of a stand-alone procedure is one written in a SQL*Forms application.
These types of procedures are not available for reference from other Oracle tools. Another limitation
of stand-alone procedures is that they are compiled at run time, which slows execution.
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84. What are cursors give different types of cursors?
PL/SQL uses cursors for all database information accesses statements. The language supports the use
two types of cursors
1.) Implicit
2.) Explicit
85. What is cold backup and hot backup (in case of Oracle)?
1. Cold Backup: It is copying the three sets of files (database files, redo logs, and control file)
when the instance is shut down. This is a straight file copy, usually from the disk directly to
tape. You must shut down the instance to guarantee a consistent copy. If a cold backup is
performed, the only option available in the event of data file loss is restoring all the files
from the latest backup. All work performed on the database since the last backup is lost.
2. Hot Backup: Some sites (such as worldwide airline reservations systems) cannot shut down
the database while making a backup copy of the files. The cold backup is not an available
option.
86. What is meant by Proactive, Retroactive and Simultaneous Update.
1. Proactive Update: The updates that are applied to database before it becomes effective
in real world.
2. Retroactive Update: The updates that are applied to database after it becomes effective
in real world.
3. Simulatneous Update: The updates that are applied to database at the same time when it
becomes effective in real world.
End of tutotiral 😇
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