Define the basic operations of the relational algebra, Database Management System

Define the basic operations of the relational algebra?   

 Ans: Basic operators of relational algebra are:

1. Union (∪) - Selects tuples which are in either P or Q or in both of them.  The duplicate tuples are removed.

R = P ∪ Q

 2. Difference or Minus (-) - eliminates common tuples from the first relation.

R = P - Q 

3.  Cartesian Product or Cross Product (×) - The cartesian product of two relations is the concatenation of tuples that are belonging to the two relations and containing all possible combination of the tuples.

R = P× Q

 4. Projection (π) - The projection of a relation is illustrated as a projection of all its tuples over some set of attributes that is it yields a vertical subset of the relation. The relation's projection T on the attribute A is presented by T [A] or πA(T),.

 5. Selection (σ) - Selects just some of the tuples, those satisfy specified criteria, from the relation. It yields a horizontal subset of a following relation.

R = σB(P)

Posted Date: 5/4/2013 1:20:58 AM | Location : United States

Related Discussions:- Define the basic operations of the relational algebra, Assignment Help, Ask Question on Define the basic operations of the relational algebra, Get Answer, Expert's Help, Define the basic operations of the relational algebra Discussions

Write discussion on Define the basic operations of the relational algebra
Your posts are moderated
Related Questions
Explain hash file organization? Hash functions a) The distribution is uniform Hash functions assign each bucket the similar number of search -key values from the set of a

what do you understand by enhanced entity-relationship

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

ER diagram on cosmetics

What are the time stamps associated with each data item? W-timestamp (Q) denotes the largest time stamp if any transaction that implemented WRITE (Q) successfully. R-timesta

What is meant by functional dependencies? Consider a relation schema R and α C R and β C R. The functional dependency α ->β  holds on relational schema R if in any legal relati

What are the basic objects of the data dictionary? Tables Domains Data elements Structures Foreign Keys

What are the features of embedded SQL? Explain. Embedded SQL - SQL could be implemented within two ways. It can be used interactively or embedded in a host language or throu

Benefits of Hashed file Organisation 1.      Insertion or search on hash-key is quick. 2.      Best if equality search is required on hash-key. Drawbacks of Hashed file

These are the binary operations; i.e., each is applied to two relations or sets. These two relations can be union compatible excluding in case of Cartesian product. Two relations R