What is DDIC or ABAP Dictionary ?
---A Data dictionary is Centralized storage location for information about the data that is stored in a database.
Table Fields:.....
---- The field names and thr datatypes of the fields contained in the table are defined here.
Technical Settings:...
----The Technical Settings define how the table is created on the database.
Data Class:
-- The data class defines the physical area of the database in which your table is locally stored.
-- It Shows what type of data the table contains.
Ex: APP0-- Master data
APP1-- Transaction data
APP2 Organizational & Customized data
Master data is data which is frequently used but rarely updated.
Transactional data which is frequently updated..
Organizational & Customized data is data ehich is defined when the system is initialized and then rarely changed..
Size Category:..
-- The Size Category determines the probable space requirement for a table in the database.
Default 0 to 4.
--- If we press F4 on the field Size Category to see the no.of records that can be maintained for the individual table.
Buffering :...
-- It is used to increase the performance of a database and to decrease the hiding of a database.
-- Buffering is required for master data because it is not changing frequently.
Types of Buffering:..
1) Single Record Buffering.
-- Its a record specific.. It can store only one record in a buffer.
2) Generic Buffering.
-- Its a field specific.. We can store only primary key fields in a buffer.
3) Fully Buffering.
--- Its a table specific... We can store the whole table ina buffer.
Delivery & Maintenance:..
Delivery Class:
---- The Delivary class control the transport of the table data when installing or updating in a client copy and when transporting between customer systems.
Use:.The delivery class is also analyze in the extended Table Maintanence(SE30) .
Ex: A: Application Table (Master and Transaction data)
C: Customer Table ( data is maintained by the customer only)
Data Browser / Table View Maintanence:
--- It is possible to display/ maintain a table or view using the maintenance tools.
1) Display / Maintenance Allowed with Restrictions.
-- Means we can't see the table contents & we Can't create entries for the table.
2) Display / Maintenance Allowed
-- Means we can see the table contents, we can able to create new entries and we can change the existing entries.
3) Display / Maintenance Not Allowed.
--- Means we can't see the table contents and we can't create new entries for the table.
Index:....
---- Indexes can defined for the table to speed up data selection from the table..
Objects of DDIC:
1) Database Table 2)View 3) Data type 4) Type group 5)domain 6) Search Help 7)Lock Objects
What is Domain and its Advantages?
--- Domain is used to define the Technical Attributes (Data Type and Length of the data type)
--- Without domain we cannot assign a fixed value for feild.
--- By the help of domain we can enter the lowercase letter but by default higher case is taken.
--- To create foreign key we should have same domain name.
What is Data Element and its Advantages?
--- It describes the individual feild of a table in a database and are used to specify the type of columns and rows in a database.
