Data Dictionary Introduction

Data dictionary is the central source of the database management system. The main functionality of the DDIC is to create or Modify the tables.

Pre-requisition for Create Table.
1. Name of the Data base table (Start with 'Y' or 'Z').
2. List of Field, Data type and length.
3. At list one key should be primary key.
4. Provide Technical Setting
5. Delivery Class.

What is Delivery Class?
Delivery class is controlling data transport of tables for installation, upgrade, and client copy, and for transporting between customer systems.

Technical Setting.
Technical Setting is the collection of Data class and Size Category.

Data Class.
Data class is the Physical area where our Data base is table is logically store.
Ex:
APPL0: Master data, transparent tables
APPL1: Transaction data, transparent tables
APPL2: Organization and customizing.

APPL0: Data that is rarely changed. Ex. Master data which is rarely change like addresses, such as names, postal addresses.

APPL1: Data that is changed a lot. Ex.Transaction data is warehouse stock that changes each time an order is placed.

APPL2: Customizing data specified when the system is configured and then changed only rarely. One example is the table T005 that contains the country codes.

Size category. Size category is used to determine size of table for Database table.

Size Category	Expected Rows
0	0               To 1,000
1	1,000        To 4,200
2	4,200        To 17,000
3	17,000      To 68,000
4	68,000      To 270,000
5	270,000    To 540,000
6	540,000    To 1,000,000
7	1,000,000 To 2,100,000
8	2,100,000 To 4,300,000
9	4,300,000 To 170,000,000

Table: Table is a collection of Multiple Record.

There are Three types of Table:
1. Transparent tables
2. Cluster tables
3. Pool tables