Data definition language, Database Management System

Assignment Help:

Data Definition Language

It organises the data in the form of columns and rows. But what does the data field column of table accumulate? How do you describe it using SQL?

The Data definition language (DDL) defines a set of commands used in the modification and creation of schema objects such as indexes, tables, views etc. These commands give the ability to create, drop and alter these objects. These commands are linked to the management and administrations of the databases. Before and after every DDL statement, the current transactions are implicitly committed, that is changes made by these commands are permanently stored in the databases. Let us talk about these commands in more detail:

CREATE TABLE Command

Syntax:

CREATE TABLE

(

Column_name1 data type (column width) [constraints], Column_name2 data type (column width) [constraints], Column_name3 data type (column width) [constraints],

...............................................

);

Where table name assigns the name of the table, column name describes the name of the field, data type specifies the data type for the field and column width distribute specified size to the field.

 

 

 


Related Discussions:- Data definition language

Eliminate repeating groups, Eliminate Repeating Groups The problem is, ...

Eliminate Repeating Groups The problem is, "Find out the list of employees, who knows DB2". For this problem we require to perform an awkward scan of the list looking for re

BI, (a) Why did SAP introduce the extended star schema?

(a) Why did SAP introduce the extended star schema?

ER diagram, #question. acompani datdbase needs to store information about e...

#question. acompani datdbase needs to store information about employees (identified by a social security number,with salary and phone as attributes) and departments (identified by

File manager-database management system, File Manager File manager ha...

File Manager File manager handles the allocation of space on disk storage. It starts and maintains the list of structures and indices described in the internal schema that is

What are the factors into account when choosing a raid level, What are the ...

What are the factors to be taken into account when choosing a RAID level? A) Monetary cost of extra disk storage requirements. B) Performance requirements in terms of number

Illustrate the fifth normal form, Fifth Normal Form (5NF) These relatio...

Fifth Normal Form (5NF) These relations still have a difficulty. While defining the 4NF we mentioned that all the attributes depend upon each other. Whereas creating the two ta

Attributes and tuple, Before we talk about the relational model in more det...

Before we talk about the relational model in more detail, let us first define some very basic terms used in this model. Tuple Every row in a table shows a record and is cal

What is foreign key, What is foreign key? Foreign Key - Let there are...

What is foreign key? Foreign Key - Let there are two relations in tables R and S. Any candidate key of the relation R that is referred in the relation S is known as the forei

A database administrator'', A database administrator''s responsibilities an...

A database administrator''s responsibilities and data contents

Operator precedence-data manipulation language, Operator Precedence The...

Operator Precedence The basic operators used in SQL are * /   - + Operators of the similar priority are evaluated From Left to right Parentheses are used to force priorit

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