In this article you will learn about basic details of SQL. It is about SQL Tutorials for Beginners | SQL Commands | SQL Syntax | SQL interview questions
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2. About Us:
In modern days economic system the most
valuable asset is knowledge. Day by day
increasing competition and invention of
cutting edge technologies are the results of
revolution in the global Educational system
and use of process oriented learning
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This process oriented learning environment
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Speed4career.com understands the nature
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We are committed to this process oriented
learning environment and set our goals to
help in creating a better modern corporate
world, more over a better world for our
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3. In this quest for creating a process oriented
learning environment www.speed4career.com
introducing a new module – Tutorial.
In this “Tutorial” module we are discussion
about the BEGINNERS lesson for the technology
related subjects.
All the Tutorials are created by the INDUSTRY
EXPERTS working on the same field for years.
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4. SQL for Beginner – PART I
About SQL:
Collection of organized data called as
DATABASE. When we define, create, query
and update the database through software
then that system known as “Database
Management System” or “DBMS”. When we
want to manage all this things through
programming language then we use “SQL” or
“Structured Programming Language”.
SQL was initially developed at IBM by Donald
D. Chamberlin and Raymond F. Boyce.
5. Data Definition Language:
Whenever you want to build or destroy or
altered any structure of database object at
that time whatever SQL commands we follow
those are inside of Data Definition
Language’s scope.
SQL Commands:
1. Create – It will create an object in database.
2. Alter – It will alter required object in
database.
3. Drop – It will destroy the whole structure of
an object in database.
6. Syntax:
1. CREATE table <table_name> (column_name
datatype,.....column_name datatype);
2. ALTER table <table_name>
add/modify/drop/rename column_name
datatype;
3. DROP table <table_name>
These are the examples of basic DDL SQL
commands. In advance SQL tutorial we will
give lots of other example.
So by this SQL command first we create a
table named “Speed4career_User_Details”
which has 5 columns.
7. Command:
CREATE TABLE Speed4career_User_Details(
User_ID VARCHAR2(10),
User_Name VARCHAR2(200),
Address VARCHAR2(1000),
City VARCHAR2(100),
Postal_Code Number,
Country VARCHAR2(100),
Phn_number VARCHAR2(20));
[Note: - We are following Oracle SQL syntax for
this tutorial. SQL is NOT case sensitive]
Suppose you want to change the column
name “Postal_code” to “Zip_code” of this
table then you have to use ALTER command
to do this.
8. Command:
ALTER TABLE Speed4career_User_Details
RENAME Postal_code TO Zip_code;
After change this now you want to add
another column “Special_User” in this table.
Command:
ALTER TABLE Speed4career_User_Details
ADD Special_User VARCHAR2(1);
Now after doing this you feel that you want
to change the table name itself and want to
give new table name as
“Speed4career_Master_Details”.
9. Command:
ALTER TABLE Speed4career_User_Details
RENAME TO Speed4career_Master_Details;
There are several more things you can do
with ALTER command.
Now you want to drop this table because you
don’t need this table anymore. So which
command you have to use?
Exactly “DROP” command.
Command:
DROP TABLE Speed4career_User_Details;
10. • SQL INTERVIEW QUESTIONS:
1. What is SQL? What is the full form of SQL?
2. Which is the subset of SQL commands used
to manipulate Oracle Database Structures?
3. Example of CREATE TABLE.
4. What is the use of DROP option in the ALTER
TABLE command?
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