Explain algorithm of er to relational mapping, Database Management System

Assignment Help:

Explain algorithm of ER To Relational Mapping ?

ER-to-Relational Mapping Algorithm:

1) Step 1: Mapping of regular entity types: For each strong entity type E, form a relation T which involves all the easy attributes of a composite attribute.

2) Step2: Mapping of weak entity types: For each weak entity type W along with owner entity type E, create relation R and involve all easy attributes (or simple components of composite attributes) of W as attributed of R. In addition, involves as foreign key attributes of R, the primary key attribute (s) of relation(s) which correspond to the owner(s) and the partial key of the weak entity type W, if any.

3) Mapping of relationship types: form a relation R, for relationship along with primary keys of participating relations A and B as foreign keys in R. Further to this, any attributes of relationship become an attribute of R also.

4) Mapping of multivalued attributes: For every multilvalued attribute A, form a new relation R. This relation R will involve an attribute corresponding to A, plus primary key attribute K-as a foreign key in R-of the relation which represents the entity category or relationship type that has A as an attribute.


Related Discussions:- Explain algorithm of er to relational mapping

What is a select operation, What is a SELECT operation? The select oper...

What is a SELECT operation? The select operation selects tuples that please a given predicate. We use the lowercase letter σ to denote selection.

What are axioms, What are axioms? Axioms or rules of inference give a s...

What are axioms? Axioms or rules of inference give a simpler technique for reasoning about

What is relational dbms, What is Relational DBMS This is our subject of...

What is Relational DBMS This is our subject of study. A DBMS is relational if the data is organized into relations, that is, tables. In RDBMS, all data are kept in the well-kno

The natural join is equal to which product, The natural join is equal to wh...

The natural join is equal to which product? The natural join is equal to Combination of projection and Cartesian product

Hashing techniques, folding method and mid square method using visual basic...

folding method and mid square method using visual basic

Difference between internal tables and extra datasets, What is the differen...

What is the difference between internal tables and extract datasets? The lines of an internal table always have the similar structure. By using extract datasets, you can ha

What is authorization graph, What is authorization graph? Passing of au...

What is authorization graph? Passing of authorization from single user to another can be shown by an authorization graph.

Create table employee and enter employee data in sql, Create table employee...

Create table employee and enter employee data in SQL? Consider the following relational schemas: EMPLOYEE (EMPLOYEE_NAME, STREET, CITY) WORKS (EMPLOYEE_NAME, COMPANYNAME, SAL

Convert the erd into its relevant relational schema, Question: Describe...

Question: Describe briefly the three parts of the Relational Model. (a) The term integrity refers to the accuracy or correctness of the data in the database. Define the fol

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd