Explain about foreign key, Database Management System

Assignment Help:

What is Foreign Key

Foreign Key: Sometimes we may have to work with an attribute that does not have a primary key of its own. To recognize its rows, we have to use the primary attribute of a related table. Such a copy of another related table's primary key is known as foreign key.

Related Discussions:- Explain about foreign key

Define null value, Define NULL value NULL value NULL means something is...

Define NULL value NULL value NULL means something is unknown. It does NOT mean null (the digit 0). Null is as well employed as attribute value for a particular entity in which

Which types of data supported by mysql, Which types of data supported by My...

Which types of data supported by MySQL for Time and Date formats? MySQL supports a number of time and date column formats: Some of them are 1) DATE 2) DATETIME 3) TIM

Creation of indexes, Creation of Indexes Automatically: When a primar...

Creation of Indexes Automatically: When a primary key or Unique constraint is show in a table definition then a unique index is formed automatically. Manually: User can

Database schemas and dependencies, 1. Staff(staffID, firstName, lastName, a...

1. Staff(staffID, firstName, lastName, availabilityID, experience, phone, mobile, email); 2. Availability(availabilityID, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday,

Explain the concept of qbe, Explain the concept of QBE? Query-by-exampl...

Explain the concept of QBE? Query-by-example represents a visual/graphical approach for accessing information in a database by the use of query templates called as skeleton tab

E-R Diagram, The H. I. Topi School of Business operates international busin...

The H. I. Topi School of Business operates international business programs in 10 locations throughout Europe. The school had its first class of graduates in 1965. The school keep

Data control, Data Control The data control mostly refers to commands that...

Data Control The data control mostly refers to commands that permit system and data privileges to be passed to several users. These commands are usually available to database admi

Define the query optimisation, Define the Query optimisation The query ...

Define the Query optimisation The query parser commonly generates a standard initial tree to correspond to an SQL query, with no doing any optimization. Such type of a canonica

Information system, what are information system hirarchy?

what are information system hirarchy?

Define check point and its impact on data base recovery, Define check point...

Define check point and its impact on data base recovery. Ans: There could be hundreds of transactions handled per minute, in a large on-line database system.

Write Your Message!

Name

Email id

Message

Verfication Code

User Account

All Pages