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

Case tools, explain at least five widly used case tools

explain at least five widly used case tools

Nested query, what is correlation in nested query

what is correlation in nested query

Natural join-table handling, Natural Join : It is the similar like Equi joi...

Natural Join : It is the similar like Equi join except one of the duplicate columns is removed in the result table. The natural join is the most usually used form of join operation

Explain about database system structure, Explain about database system stru...

Explain about database system structure? Storage manager Authorization and integrity manager Transaction manager File manager Buffer manager Storage manager

Assignment, how does Btree differ from a B+ - tree?

how does Btree differ from a B+ - tree?

Explain the shadow paging recovery technique, Explain the shadow paging rec...

Explain the shadow paging recovery technique.  Ans: Shadow paging is a method used to acquire atomic and durable transactions, and provides the capability to manipulate pages i

Relationship for college database, Using the concepts defined previous, we ...

Using the concepts defined previous, we have identified that strong entities in COLLEGE database are FACULTY, STUDENT, COURSE and DEPARTMENT. This database also has one weak entity

Express the ways provided by mysql for pattern matching, Express the ways p...

Express the ways provided by MySQL for Pattern Matching? MySQL provides two kinds of pattern matching. 1) One is based on SQL patterns 2) Regular expressions.

Relational algebra operators, Question 1 Draw a Data Flow Diagram for a...

Question 1 Draw a Data Flow Diagram for a University scenario Question 2 Discuss the following with suitable examples Relational Algebra Operators Database Pla

Database, 3. (10 points) Assume that you have been presented with the follo...

3. (10 points) Assume that you have been presented with the following relation for the Baxter Aviation database: Charters (Pilot#, Pilot name, Aircraft ID#, #seats, Village, Fligh

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