Domains, Database Management System

Assignment Help:

A domain is a set of permissible values that can be given to an attribute. So each attribute in a table has a definite domain. Values to these attributes cannot be assigned outside their domains.

In the example given above if domain of PERSON_ID is a set of integer values from 1 to

1000 than a value outside this range will not be valid. Many other common domains may be age between 1 and 150. The domain can be definite by assigning a type or a format or a range to an attribute. For instance, a domain for a number 501 to 999 can be particular by having a 3-digit number format having a range of values between 501 and 999. Therefore, please note the domains can also be non-contiguous. For instance, the enrolment number of IGNOU has the last digit as the check digit, therefore the nine- digit enrolment numbers are non continuous.


Related Discussions:- Domains

Why like predicate used for, Why Like predicate used for? LIKE predicat...

Why Like predicate used for? LIKE predicate: The LIKE predicate searches for strings in which have a certain pattern.

Mention constraints to create command ddl, Mention the type of constraints ...

Mention the type of constraints we can specify in the CREATE command of DDL. The type of constraints that can be specified are as follows:- PRIMARY KEY, NOT NULL, UNIQUE, FOR

Define forms based interfaces, Define Forms Based Interfaces? Forms-Bas...

Define Forms Based Interfaces? Forms-Based Interfaces - A forms-based interface display a form to each user. Forms are commonly designed and programmed for naive users and inte

Discuss the mechanism to read data from and write to a disk, Discuss the me...

Discuss the mechanism to read data from and write to a disk? Disk read/write heads are mechanisms in which read data from or write data to disk drives. The heads have gone by

Explain alternate key, Explain Alternate key? Alternate Key - All the...

Explain Alternate key? Alternate Key - All the candidate keys except primary key are known as alternate keys.

Backup - restore utilities, These are designed to reduce the effects of a d...

These are designed to reduce the effects of a database failure and make sure a database is restored to a consistent state if a failure does arise. Manual backup/restore utilities n

What is a candidate key, What is a candidate key? Minimal super keys ar...

What is a candidate key? Minimal super keys are known as candidate keys.

Dbms, Retrieve the S&S In-Chapter Database (in Microsoft Access format) fro...

Retrieve the S&S In-Chapter Database (in Microsoft Access format) from the text's Web site (or create the tables in Table 4-5 in a relational DBMS product). Write queries to answer

What are the disadvantages of file-processing system, What are the disadvan...

What are the disadvantages of file-processing system?  Ans: The Disadvantages of File-Processing System a. Data redundancy and inconsistency - Data redundancy means not nece

What is meant by buffer blocks and disk buffer, What is meant by buffer blo...

What is meant by buffer blocks and disk buffer   The blocks residing temporarily in main memory are referred to as buffer blocks. The area of memory where blocks reside t

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