21. What is 5NF?
A table is in fifth normal form (5NF) or Project-Join Normal Form (PJNF) if it is in 4NF and it cannot have a lossless decomposition into any number of smaller tables.
22. What is a query?
A query with respect to DBMS relates to user commands that are used to interact with a data base.
23. What is meant by query optimization?
The phase that identifies an efficient execution plan for evaluating a query that has the least estimated cost is referred to as query optimization.
24. What is an attribute?
It is a particular property, which describes the entity.
25. What is RDBMS?
Relational Data Base Management Systems (RDBMS) are database management systems that maintain data records and indices in tables.
26. Whats difference between DBMS and RDBMS?
DBMS provides a systematic and organized way of storing, managing and retrieving from collection of logically related information. RDBMS also provides what DBMS provides but above that it provides relationship integrity.
27. What is SQL?
SQL stands for Structured Query Language. SQL is an ANSI (American National Standards Institute) standard computer language for accessing and manipulating database systems. SQL statements are used to retrieve and update data in a database.
28. What is Stored Procedure?
A stored procedure is a named group of SQL statements that have been previously created and stored in the server database.
29. What is a view?
A view may be a subset of the database or it may contain virtual data that is derived from the database files but is not explicitly stored.
30. What is Trigger?
A trigger is a SQL procedure that initiates an action when an event (INSERT, DELETE or UPDATE) occurs.
