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,
www.assignmenthelp.net
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;
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
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