Super keys, Database Management System

A super key is an attribute or set of attributes used to recognize the records uniquely in a relation.

For instance, in the Relation PERSON defines earlier PERSON_ID is a super key since PERSON_ID is unique for every person. Likewise (PERSON_ID, AGE) and (PERSON_ID, NAME) are also super keys of the relation PERSON as their combination is also unique for each record.

Posted Date: 3/6/2013 5:23:51 AM | Location : United States







Related Discussions:- Super keys, Assignment Help, Ask Question on Super keys, Get Answer, Expert's Help, Super keys Discussions

Write discussion on Super keys
Your posts are moderated
Related Questions
Define the following constraints for the table client. (i) BAL_DUE must be at least 1000. (ii) NAME is a unique key. (i)ALTER TABLE CLIENT ADD CONSTRAINT CLIENT_BAL_DUE_C1

System error :These contain errors in database system or the OS, example, deadlocks.Such errors are fairly hard to detect and need reprogramming the erroneous components of the sys

State The position of object at any moment is called state. An object can have many states depend upon time. After receiving some input instructions, the object can change its

What is meant by buffer blocks and disk buffer   The blocks residing temporarily in main memory are referred to as buffer blocks. The area of memory where blocks reside t

What is an entity relationship model? The entity relationship model is a set of basic objects known as entities and relationship between those objects. An entity is a thing or

What are stand-alone procedures? Procedures that are not part of a package are called as stand-alone because they independently defined. A good example of a stand-alone procedu

What are the two methods for dealing deadlock problem? The two procedures for dealing deadlock problem is deadlock detection and deadlock recovery.

Define a job scheduling strategy that will meet business requirement of reporting availability by 6am CST for the following cubes? Show the job scheduling dependencies in a pictori

What is substitutability? Any method of a class-say A can equally well be adjured with any object belonging to any subclasses B of A. This characteristic leads to code reuse, a

What are the two types of errors? The two types of errors are: a) Logical error b) System error