What is Data Dictionary ?
The DATA DICTIONARY is a comprehensive set of tables and views owned by the DBA users SYS and SYSTEM, which activates when ORACLE is initially installed, and is... Read more »
‘Database Interview Questions’ - KyaPoocha.com
What is a package ?
A PACKAGE is a PL/SQL object that groups PL/SQL types, variables, SQL cursors, exceptions,procedures, and functions.Each package has a specification and a body.... Read more »
What is SNAPSHOT ? What is a SNAPSHOT LOG ?
A SNAPSHOT is a means of creating a local copy of remote data. A snapshot can be used to replicate all or part of a single table, or to replicate the result... Read more »
What is a DATABASE trigger ? What is a DATABASE Procedure ?
A DATABASE TRIGGER is a stored procedure associated with a table that ORACLE7 automatically executes on one or more specified events (BEFORE or AFTER an INSERT,UPDATE... Read more »
What is ROWID ? What are its components ?
ROWID is the logical address of a row, and it is unique within the database.The ROWID is broken into three sections: left,middle,, and right (corresponding to... Read more »
Can we define our OWN EXCEPTION ? How to raise it ?
In the DECLARATION part define a variable of type exception. In the excecution part call the exception using RAISE exception_name. In the exception part handle the... Read more »
What is APPLICATION PARTITIONING ?
PL/SQL is the language used for both client-side Oracle forms applications and server-side database triggers and stored procedures and there is a PL/SQl engine in... Read more »
What is the DIFFERENCE between PRE-QUERY and POST-QUERY ?
PRE-QUERY fires ONLY ONCE during EXECUTE-QUERY or COUNT-QUERY processing, just before Oracle Forms constructs and issues the SELECT statement to identify rows... Read more »
How do you evaluate performance ?
Using SQL TRACE. It is an utility that can monitor and report on database performance when one or more queries are run against the database. It is used to gather... Read more »
What is the Purpose of ERASE command ?
ERASE removes an indicated Global variable & releases the memory associated with it Read more »
What is LookUp table ?
When a foreign key exists in a table, the foreign key’s table is sometimes referred to as a lookup table. The DEPARTMENT table in our example is a lookup table... Read more »
DBMS V/s File Processing System
DBMS Ø Redundancy is controlled. Ø Unauthorised access is restricted. Ø Providing multiple user interfaces. Ø Enforcing integrity constraints. Ø Providing backup... Read more »
What are levels of Abstraction?
The are three levels of abstraction: Ø Physical level: The lowest level of abstraction describes how data are stored. Ø Logical level: The next higher level of... Read more »
Define the “integrity rules”.
There are two Integrity rules. Ø Entity Integrity: States that “Primary key cannot have NULL value” Ø Referential Integrity: States that “Foreign Key can... Read more »
What is System R?
System R was designed and developed over a period of 1974-79 at IBM San Jose Research Center. It is a prototype and its purpose was to demonstrate that it is possible... Read more »
How does Tuple-oriented relational calculus differ from domain-oriented relational calculus?
The tuple-oriented calculus uses a tuple variables i.e., variable whose only permitted values are tuples of that relation. E.g. QUEL The domain-oriented calculus... Read more »
What is Fully Functional dependency?
It is based on concept of full functional dependency. A functional dependency X Y is full functional dependency if removal of any attribute A from X means that the... Read more »
What is Domain-Key Normal Form?
A relation is said to be in DKNF if all constraints and dependencies that should hold on the the constraint can be enforced by simply enforcing the domain constraint... Read more »
What are partial, alternate,, artificial, compound and natural key?
Partial Key: It is a set of attributes that can uniquely identify weak entities and that are related to same owner entity. It is sometime called as Discriminator. Alternate... Read more »
What is an Oracle Instance?
The Oracle system processes, also known as Oracle background processes, provide functions for the user processes—functions that would otherwise be done by the... Read more »