Explain weak and strong entity type, Database Management System

Assignment Help:

Explain weak and strong entity type ?

Weak and Strong entity type: An entity set which does not have a primary key is referred to as a weak entity set. The existence of a weak entity set depends on the existence of a strong entity set; it must associate to the strong set via a on-to-many relationship set. A discriminator of a weak entity set is the set of attributes that distinguishes between all the entities of a weak entity set. The primary key of a weak entity set is formed by the primary key of the strong entity set on that the weak entity set is existence depends, plus the weak entity set's discriminator.


Related Discussions:- Explain weak and strong entity type

Fragmentation, Differentiate between horizontal & mixed horizontal fragment...

Differentiate between horizontal & mixed horizontal fragmentation?

Name the metrics for selecting top algorithm, Name the metrics for selectin...

Name the metrics for selecting top algorithm There are a number of metrics for selecting top algorithm: i) Computational complexity: Computational complexity refers to eff

Describe sequential file organization, Describe sequential file organizatio...

Describe sequential file organization.  Explain the rules for (i)  Inserting a new record. (ii)  Deleting an existing record.          Ans:A sequential f

Using column aliases-data manipulation language, Using Column aliases E...

Using Column aliases Example: To print column names as NAME and ANNUAL SALARY SELECT ENAME "NAME", SAL*12 "ANNUAL SALARY" FROM EMP;

Index and tree structure, Index And Tree Structure Let us talk about th...

Index And Tree Structure Let us talk about the data structure that is used for creating indexes. Can we use Binary Search Tree (BST) as Indexes? Let us initial reconsider

The file based system in dbms, The File Based System File based systems...

The File Based System File based systems are an early attempt to computerise the manual filing system. For example, a manual file can be set up to hold all the correspondence r

Assignment, Research Value: 7% Due Date: 17-Sep-2018 Return Date: 11-Oct-2...

Research Value: 7% Due Date: 17-Sep-2018 Return Date: 11-Oct-2018 Length: 700 words Submission method options: Alternative submission method Task back to top You are required to

Example of sequences, Example : Create a sequence named SEQSS that starts a...

Example : Create a sequence named SEQSS that starts at 105, has a step of 1 and can take maximum value as 2000.  CREATE SEQUENCE SEQSS START WITH 105 INCREMENT BY 1 MAX VA

Define partial, Partial Key : It is a group of attributes that can uniquel...

Partial Key : It is a group of attributes that can uniquely identify small entities and that are related to same base entity. It is sometime named as Discriminator.  Altern

List the types of authorization, List the types of authorization. A) R...

List the types of authorization. A) Read authorization B) Write authorization C) Update authorization D) Drop authorization

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