Alter table command, Database Management System

Assignment Help:

ALTER TABLE Command: This command is used for variation of existing structure of the table in the given situation:

  • When a new column is to be added to the table structure.
  • When the existing column definition has to be altered, i.e., changing the width of the data type or the data type itself.
  • When integrity constraints have to be dropped or included.
  • When a constraint has to be allowed or not allowed.

Syntax

ALTER TABLE

ADD ( ...); ALTER TABLE
MODIFY ( ...);

ALTER TABLE

ADD CONSTRAINT < constraint type>(field name);

ALTER TABLE

DROP;

ALTER TABLE

ENABLE/DISABLE ;

You require to put many constraints like that the database integrity is not compromised.

 


Related Discussions:- Alter table command

What is sql server agent, What is SQL Server Agent? SQL Server agent pl...

What is SQL Server Agent? SQL Server agent plays a significant role in the day-to-day tasks of a database administrator (DBA). It is often overlooked as one of the major tools

Sources of utilities for a dbms, There are three main sources of utilities ...

There are three main sources of utilities and applications for a DBMS: a. Vendor applications and utilities are given for working with or maintaining the database, and generally

Implementing a data mining algorithm, i need to implememnt a treee based mi...

i need to implememnt a treee based mining algorithm. do you have an expert that can do that?

Stock market, need requirement analysis for database management of stock ma...

need requirement analysis for database management of stock market

Explain the two constraints check and foreign key in sql, Explain the two c...

Explain the two constraints, check and foreign key in SQL along with an example for each. Give the syntax. CHECK constraint - CHECK constraint specifies an expression which

Describe deductive databases and relational databases, Problem : (b) A ...

Problem : (b) A deductive database system is essentially the outcome of applying mathematics logic to database management, where logic is used for both data representation and

What does authentication refer, What does authentication refer? Authent...

What does authentication refer? Authentication refers to the task of verifying the uniqueness of a person.

What is inheritance, What is inheritance? Define it in detail?  Inheri...

What is inheritance? Define it in detail?  Inheritance Inheritance can be at the levels of types, or at the level of tables we first consider inheritance of types, then i

MULTI-LIST FILE ORGANIZATION, sir, could anybody help me in getting complet...

sir, could anybody help me in getting complete information about the mentioned topic

Explain a data dictionary, What is a data dictionary? Data Dictionary ...

What is a data dictionary? Data Dictionary is a main source of data in a data management system.  Its major function is to carry the creation and management of data definition

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