The document compares and contrasts SQL, MySQL, and Oracle databases. It discusses the definitions of SQL, MySQL, and Oracle and how they are different types of database management systems. It also provides examples of how to create tables, define primary keys, add foreign keys, create indexes, drop tables, and alter tables using SQL, MySQL, and Oracle syntax.

1. Difference Between
SQL / MYSQL / ORACLE
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2. SQL Database
SQL (Structured Query Language) is a database computer language designed for managing data
in relational database management systems (RDBMS).
MYSQL Database
MySQL is a relational database management system (RDBMS) that runs as a server providing
multi-user access to a number of databases.
ORACLE Database
Oracle is the name of the database management system that comes from Oracle Corporation.

3. PRIMARY KEY
A Primary Key is a column or combination of columns whose values uniquely identify a
row or record in the table.
Examples for specifying a Primary Key,
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SQL MYSQL ORACLE
Primary
Key
CREATE table table_name
(
id integer PRIMARY KEY,
FirstName varchar(30),
LastName varchar(30) );
CREATE table table_name
(
id integer, FirstName
varchar(30), LastName
varchar(30), PRIMARY KEY
(id) );
CREATE table table_name
(
id integer PRIMARY KEY,
FirstName varchar(30),
LastName varchar(30) );
Specifying
a primary
key by
Altering a
table
ALTER TABLE table_name
ADD PRIMARY KEY (id);
ALTER TABLE table_name
ADD PRIMARY KEY (id);
ALTER TABLE table_name
ADD PRIMARY KEY (id);
DROP
TABLE
DROP TABLE table_name; DROP TABLE table_name; DROP TABLE table_name;

4. Sample Output
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Sample output for
CREATE Table
Sample output for
DROP Table

5. FOREIGN KEY
A FOREIGN KEY in one table points to a PRIMARY KEY in another table.
Examples for specifying a Foreign key when creating a table (using CREATE TABLE) or
by changing the existing table structure (using ALTER TABLE).
Table1: Student
Table2: Book
Column Name Datatype characteristic
BookId integer Primary Key
BookName varchar
Student_Sid integer Foreign Key
Amount integer
Column Name Datatype characteristic
Sid integer Primary Key
LastName varchar
FirstName varchar

6. Foreign Key
SQL MYSQL ORACLE
Foreign Key
Create table Book (
BookId integer PRIMARY KEY,
BookName varchar(30),
Amount integer,
Student_Sid interger
references Student(Sid));
Create table Book (
BookId integer,
BookName varchar(30),
Student_Sid integer,
Amount integer,
Primary Key (BookId),
Foreign Key (Student_Sid)
references Student(Sid));
Create table Book (
BookId integer PRIMARY KEY,
BookName varchar(30),
Amount integer,
Student_Sid integer
references Student(Sid));
Specifying a
Foreign Key
by Altering a
table
ALTER table Book ADD
FOREIGN KEY (Student_Sid)
references Student(Sid);
ALTER table Book ADD
FOREIGN KEY (Student_Sid)
references Student(Sid);
ALTER table Book ADD
FOREIGN KEY (Student_Sid)
references Student(Sid);
DROP Table DropTABLE Book; Drop TABLE Book; drop table Book cascade
constraints;
Note: if foreign key are
available in that table

7. Sample Output
Sample Output for
CREATE Table
Sample Output for
Drop Table

8. CREATE TABLE
SQL MYSQL ORACLE
The CREATE TABLE
statement is used to create
a table in a database.
CREATE TABLE table_name (
column_name1 data_type,
column_name2 data_type, .... );
CREATE TABLE table_name (
column_name1 data_type,
column_name2 data_type, .... );
CREATE TABLE table_name (
column_name1 data_type,
column_name2 data_type, .... );
Creates an index on a
table. Duplicate values are
allowed.
CREATE INDEX index_name
ON table_name (column_name);
CREATE INDEX index_name
ON table_name (column_name);
CREATE INDEX index_name
ON table_name (column_name);
Creates a unique index on
a table. Duplicate values
are not allowed.
CREATE UNIQUE INDEX
index_name
ON table_name (column_name);
CREATE UNIQUE INDEX
index_name
ON table_name (column_name);
CREATE UNIQUE INDEX
index_name
ON table_name (column_name);
Create View syntax
CREATE VIEW view_name AS
SELECT column_name(s)
FROM table_name
WHERE condition;
CREATE VIEW view_name AS
SELECT column_name(s)
FROM table_name
WHERE condition;
CREATE VIEW view_name AS
SELECT column_name(s)
FROM table_name
WHERE condition;

9. DROP TABLE
SQL MYSQL ORACLE
It is used to delete a
Table.
DROP TABLE Student; DROP TABLE Student; DROP TABLE Student;
It is used to delete a
database.
DROP DATABASE
database_name
DROP DATABASE
database_name
DROP DATABASE
database_name
Delete the data inside
the table only
TRUNCATE TABLE
table_name
TRUNCATE TABLE table_name TRUNCATE TABLE table_name
The DROP INDEX
statement is used to
delete an index in a
table.
DROP INDEX
table_name.index_name
ALTER TABLE table_name
DROP INDEX index_name
DROP INDEX index_name

10. ALTER TABLE
SQL MYSQL ORACLE
Rename the table
name
ALTER TABLE table_name
RENAME TO new_table_name;
ALTER TABLE table_name
RENAME TO
new_table_name;
ALTER TABLE table_name
RENAME TO
new_table_name;
Add a column in a
table
ALTER TABLE table_name
ADD column_name datatype;
ALTER TABLE table_name
ADD column_name column-
definition;
ALTER TABLE table_name
ADD column_name column-
definition;
Delete a column in a
table
ALTER TABLE table_name
DROP COLUMN column_name
ALTER TABLE table_name
DROP COLUMN
column_name
ALTER TABLE table_name
DROP COLUMN
column_name
Change the data type
of a column in a table
ALTER TABLE table_name
ALTER COLUMN column_name
datatype
ALTER TABLE table_name
ALTER COLUMN
column_name datatype
ALTER TABLE table_name
ALTER COLUMN
column_name datatype

11. References
http://en.wikipedia.org/wiki/Sql
Dr. Chen’s homepage: http://bit.csc.lsu.edu/~chen/chen.html
Database Systems: A First Course, J.D. Ullman & J. Widom
http://en.wikipedia.org/wiki/Oracle
http://en.wikipedia.org/wiki/Mysql
http://www.w3schools.com/sql/default.asp

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