Extended e-r features, Database Management System

Assignment Help:

Although, the essential features of E-R diagrams are enough to design many database situations. Though, with more difficult relations and advanced database applications, it is need to move to enhanced features of E-R models. The three such features are:

  • Generalisation
  • Specialisation, and
  • Aggregation

In this part, we have described them with the help of an example. More detail on them are available in the further readings and MCS-043.

Example: A bank has an account entity set. The accounts of the bank can be of two parts:

  • Savings account
  • Current account

The statement as above shows a specialisation/generalisation hierarchy. It can be shown as

1135_Extended E-R features.png

Figure: Generalisation and Specialisation hierarchy


Related Discussions:- Extended e-r features

Complexity- drawbacks of data distribution, Complexity : A distributed DBMS...

Complexity : A distributed DBMS that is available, reliable, and secure is inherently more difficult than a centralised DBMS. Though, adequate data replication is essential to have

Explain the fourth normal form, Fourth Normal Form (4NF) When attribut...

Fourth Normal Form (4NF) When attributes in a relation have multi-valued dependency, further Normalization to 4NF and 5NF are needed. Let us first find out what multi-valued d

Query, Use a Set operator to create a list of academics who have written or...

Use a Set operator to create a list of academics who have written or co-written less than 5 papers and also have greater than 3 interests. List their academic number in the output.

Explain dynamic two-phase locking, Explain Dynamic Two-Phase Locking H...

Explain Dynamic Two-Phase Locking Here a transaction locks a data item instantly earlier than any operation is applied on the data item.  After finishing all the operations on

Express the queries in relational algebra, Question: This question refe...

Question: This question refers to the database schema. a) Express the following queries in SQL: (i) Write the SQL code that will create the table Company. Your answer sh

Structure of client server systems, Structure of Client Server Systems: In ...

Structure of Client Server Systems: In client/server architecture, clients show users who require services while servers give services. Both client and server are a combination of

Architectural standard, Architectural standard: Designation : Archit...

Architectural standard: Designation : Architect , Consultant Job Profile : As a part of Oracle Fusion Middleware at Satyam, I am involved with Presales, Delivery, A

Locks, Locks: Serialisabilty is just a test whether a given interleaved sch...

Locks: Serialisabilty is just a test whether a given interleaved schedule is ok or has a concurrency related trouble. Though, it does not make sure that the interleaved concurrent

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