8.Oracle Date Base Table

Ø  Tables are the basic unit of data storage in a Database.

Ø  Data is stored in rows and columns .

Ø  We define a table with a table name ,each column with a column name,  And each  row has a unique row id.   

Ø  A table has a specified number of columns, but can have any number of rows

Ø  If data that are not physically stored in the database  it can be called as Views

Types Of Tables:

àRelational Tables: It have simple columns and are the   most common table type

                      Eg: emp

                                CREATE TABLE emp (empno   NUMBER(3),
                                name    VARCHAR2(20),
                                 address ADDRESS_OBJ);

Ø  Object Tables:  An object table is a special kind of table in which each row represents an object

Ø  Before Creating Object Table we have to create an Object Type

Ø  To create Object  type .

Ø                       CREATE OR REPLACE TYPE address_obj as OBJECT(
                 street VARCHAR2(20),
                 city VARCHAR2(20),
                 state CHAR(2),
                 zip CHAR(5));

Ø  Then We can create  its object Tables

Ø                      E.g: CREATE TABLE address_table OF ADDRESS_OBJ;

Ø                              CREATE TABLE address_table _new OF ADDRESS_OBJ;

Ø  à Heap  Organized table

Ø             àIt Does not Store Rows In any Particular Order

Ø  à Index Organised Table

Ø            àIt Orders rows According to the primary key Value.