Difference Between

SQL / MYSQL / ORACLE

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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.

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;

Sample Output

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Sample output for CREATE Table

Sample output for DROP Table

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  

Foreign Key

SQL MYSQL ORACLE

Foreign KeyCreate 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 integerreferences 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

Sample Output

Sample Output for CREATE Table

Sample Output for Drop Table

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_nameON table_name (column_name);

CREATE INDEX index_nameON table_name (column_name);

CREATE INDEX index_nameON 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 ASSELECT column_name(s)

FROM table_nameWHERE condition;

CREATE VIEW view_name ASSELECT column_name(s)

FROM table_nameWHERE condition;

CREATE VIEW view_name ASSELECT column_name(s)

FROM table_nameWHERE condition;

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

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_nameDROP COLUMN column_name

ALTER TABLE table_nameDROP COLUMN

column_name

ALTER TABLE table_nameDROP COLUMN

column_name

Change the data type of a column in a table

ALTER TABLE table_nameALTER COLUMN column_name

datatype

ALTER TABLE table_nameALTER COLUMN

column_name datatype

ALTER TABLE table_nameALTER COLUMN

column_name datatype

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. Widomhttp://en.wikipedia.org/wiki/Oracle

http://en.wikipedia.org/wiki/Mysql

http://www.w3schools.com/sql/default.asp

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