What is a foreign key, Database Management System

Assignment Help:

What is a foreign key, and what is it used for?

A foreign key is used to establish relationships between relations in the relational model. Technically, a foreign key is a column (or columns) appearing in one relation that is (are) the primary key of another table. Although there might be exceptions, the values in the foreign key columns usually must correspond to values existing in the set of primary key values. This correspondence necessity is created in a database using a referential integrity constraint on the foreign key.

 

 


Related Discussions:- What is a foreign key

Scope of traffic data management, A TDMS project plan is not a typical Info...

A TDMS project plan is not a typical Information Technology project plan; therefore, a traffic data project has several unique characteristics: Traffic data management system

Describe in brief about the sequence diagrams, Describe in brief about the ...

Describe in brief about the Sequence Diagrams Sequence diagrams are interaction diagrams which emphasize time ordering of messages. In UML, it is shown as a table which shows

What is olap, What is OLAP? OnLine Analytical Processing (OLAP) is a Bu...

What is OLAP? OnLine Analytical Processing (OLAP) is a Business Intelligence (BI) reporting system. OLAP gives the user with the capability to sum, count, average and do other

Define query language, Define query language?   A query is a statement ...

Define query language?   A query is a statement requesting the retrieval of information. The portion of DML that includes information retrieval is known as a query language.

Tables, does tables are called relations

does tables are called relations

Create table statements for original database, MySQL statements for extendi...

MySQL statements for extending the database to incorporate new facilities Deliverables for submission You must submit the following deliverables in the Assignment Dropbox in

Two approaches to store relations in distributed database, What are the two...

What are the two approaches to store relations in distributed database? a) Replication b) Fragmentation

In a relational model how relations are termed, In a relational model how r...

In a relational model how relations are termed? In a relational model, relations are termed as tables. (The term ‘relation’ is the technical name of the ‘table’ in RDBMS)

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

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