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

Which database level is closest to the users, Which database level is close...

Which database level is closest to the users? External database level is closest to the users.

Managing Data in Databases, Answer SQL Queries to extract data from data ta...

Answer SQL Queries to extract data from data tables and questions on mapping conceptual data models into relational data model.

Ddl compiler-database management system, DDL Compiler The DDL compile...

DDL Compiler The DDL compiler changes the data definition statements (such as CREATE TABLE .... in SQL) into a set of tables having metadata tables. These tables have infor

What is object containment, What is object containment? References amon...

What is object containment? References among objects can be used to model dissimilar real-world concepts.

When are two schedules said to be view equivalent, When are two schedules s...

When are two schedules said to be view equivalent?     Ans: Two schedules that is denoted as S and S' are said to be view equivalent if the subsequent three conditions are met

Define the phases of two phase locking protocol, Define the phases of two p...

Define the phases of two phase locking protocol Growing phase: a transaction may get locks but not release any lock. Shrinking phase: a transaction might be release locks bu

Explain what is rdbms, Explain what is RDBMS ? RDBMS - RDBMS is a datab...

Explain what is RDBMS ? RDBMS - RDBMS is a database management system (DBMS) which stores data within the form of relations. Relational databases are powerful since they need f

Difference between left outer join and right outer join, Difference between...

Difference between LEFT OUTER JOIN and RIGHT OUTER JOIN In left outer join tuples from the left-hand-side relation which do not match any tuple in the right-hand-side relation

Oracle, how oracle can be used

how oracle can be used

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