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
Discuss along with examples about several types of attributes present in the ER model? Types of Attributes are: • SIMPLE attributes are attributes which are drawn from the ato

Primary index A primary index is a file that has a sorted series of records having two columns: a block address for that key field in the data file; and the ordering key field.

WRITE SHORT NOTES ON INDEX STRUCTURE OF FILES? There are two basic parts of indices 1.   Ordered indices 2.   Hash indices Every technique must be evaluated on the bas

Write an sql statement to find what is the percentage of home policies which are from the state of Arizona out of all Home policies by Policy Value.

There are many simple and complex approaches to implement. These reports are based on some views or certain query. The following number of reports can be built. 1. The averag

DISADVANTAGES OF RDBMS

Describe queries with complex types? The present extension of the SQL query language deal with the complex type Let us start with the simple example: Find the title and t

Differentiate between static hashing and dynamic hashing.  Ans: Static Hashing comprises the number of primary pages in the directory fixed. So, while a bucket is full, we requ

Define the terms i) Entity set ii) Relationship set Entity set: The set of all entities of the similar type is termed as an entity set. Relationship set: The set of all rela

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