Referential integrity, Database Management System

Assignment Help:

It can be easily defined as:

The database must not have any unmatched foreign key values.

The term "unmatched foreign key value" means a foreign key value for which there does not exist a matching value of the relevant candidate key in the relevant target (referenced) relation. For instance, any value existing in the EMPID attribute in ASSIGNMENT relation must be in the EMPLOYEE relation. That is, the only EMPIDs that can be in the EMPLOYEE relation are 101, 102 and 103 for the instance / present state of the database given in Figure. If we want to insert a tuple with EMPID value 104 in the ASSIGNMENT relation, it will cause violation of referential integrity constraint. Logically it is very obvious after all the employee 104 does not be, so how can s/he be assigned any work.


Related Discussions:- Referential integrity

Explain normalization, What is Normalization? Database normalization is...

What is Normalization? Database normalization is a data design and organization method applied to data structures based on rules that help building relational databases. In rel

What is data mining?, Question 1 Define OLTP? Explain the Differences betw...

Question 1 Define OLTP? Explain the Differences between OLTP and Data Warehouse Question 2 What is Architecture? Explain various components involved in it Question

Explain algorithm of er to relational mapping, Explain algorithm of ER To R...

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 relatio

Why is database redesign necessary, Why is database redesign necessary? ...

Why is database redesign necessary? Database redesign is essential for two reasons. First, redesign is essential both to fix mistakes made during the initial database design. S

Develop motel point of sale software, Project Description: I need a poin...

Project Description: I need a point of sale for motels. It needs to run on windows and requires being network able so that we can have more than one computer using it at once.

Two phase locking technique, growing phase and shrinking phase are disjoint...

growing phase and shrinking phase are disjoint, why ?

Define 1 nf normal form, 1 NF Normal Form The domain of attribute must...

1 NF Normal Form The domain of attribute must add only atomic (simple, indivisible) values First normal form (Minimal Form or 1NF) is a normal form need in database normalizat

Explain current page table and shadow page table, Explain current page tabl...

Explain current page table and shadow page table. The key idea behind the shadow paging method is to maintain two page tables during the life of the transaction: the current pa

Property management database, You are to write a property management databa...

You are to write a property management database program that allows a real estate agent to view, add, search, and save property listings. The program is to do the following: 1.

Design and build a data mart, You are required to design and build a data m...

You are required to design and build a data mart/data warehouse using Oracle. A national bank allocates funding every year for its local branches to provide temporary staff cove

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