What is data defination language, Database Management System

Assignment Help:

What is DDL? Make a list of commands with short description used in DDL

Ans: Data Definition Language that is abbreviated as DDL is a computer language for defining data structures. The phrase was first introduced in relation to the Codasyl database model in which the schema of the database was written in a Data Definition Language explaining the records, fields, and "sets" making up the user Data Model.

  List of DDL commands:

  (a) To define a table/ relation

  CREATE TABLE ------

  (b) To eliminate table/relation definition

DROP TABLE ----

  (iii) To alter the definition of an existing table

  ALTER TABLE-------


Related Discussions:- What is data defination language

Describe the concept of aggregation, Aggregation Aggregation is strong...

Aggregation Aggregation is stronger form of association. It represents the "has-a" or "part-of" relationship. An aggregation association depicts a complex object which is comp

Having clause with sub queries, Having Clause with sub queries: First we h...

Having Clause with sub queries: First we have to recollect the GROUP BYclause. The following query searches the minimum salary in every department. SELECT DEPTNO, MIN (SAL)

Database model, Why older data models are being replaced by new data modell...

Why older data models are being replaced by new data modelling 100 words accepted#

What is a view, What is a view?  Make a view of EMP table named DEPT 20, to...

What is a view?  Make a view of EMP table named DEPT 20, to display the employees in department 20 and their annual salary.  Ans:  View is a virtual table that does not consist

Example of database optimisation, Create 1 experiment to demonstrate an asp...

Create 1 experiment to demonstrate an aspect of query optimisation by using access-path structures (indexes), decomposition, or denormalisation. Once satisfied with your experiment

Storage of database on hard disks, Storage Of Database On Hard Disks At...

Storage Of Database On Hard Disks At this point, it is worthwhile to note the difference among the terms file Organisation and the access method. A file organisation shows to t

Physical records, Physical Records These are the records that are store...

Physical Records These are the records that are stored in the secondary storage devices. For the database relation, physical records are the group of fields kept in adjacent me

Briefly explain the state diagram by taking one example, Briefly explain th...

Briefly explain the state diagram by taking one example. State Diagram - An object can be given a sequence of input instructions. The state of the object can vary depending u

What are the two aspect to the implementation of association, What are the ...

What are the two distinct aspects to the implementation of associations? i) It is required to define data declarations which will enable details of actual links to be stored. I

Explain outer join, Explain outer join? Outer Join - If there are any...

Explain outer join? Outer Join - If there are any values in one table which do not have corresponding value(s) in the other, in an equi-join which will not be chosen. Such ro

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