dictionary - chapter 01

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1.01.1 Version 2.0

ASCENT - Strategic Initiative (SAP Development ABAP) ABAP Dictionary

SAP Release 4.0B Overview of the ABAP Dictionary

BC030_2.01.1

The ABAP Dict ionary

• The ABAP Dictionary



1.01.2 Version 2.0



BC030_2.01.2

Objectives

• The participants will be able to:

– Define the ABAP dictionary

– Describe the functions of the ABAP Dictionary

– Describe the basic objects of the ABAP

Dictionary

– Explain the how Database Utility interfaces with

the ABAP Dictionary and the underlying

database

• Objectives

In previous versions of SAP, ABAP was known as ABAP/4.



1.01.3 Version 2.0



BC030_2.01.3

What is a Data Dictionary?

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• A data dictionary is a centralized storage location for information about the data that is

stored in a database. This information is often called metadata (data about data).• A data dictionary provides answers to questions such as:

– What data is contained in the database?

– What are the attributes of this data: name, length, format, etc.?

– What relationships exist among different data objects?

• SAP’s data dictionary is called the ABAP Dictionary. As an ABAP developer, it is

unlikely that you will be responsible for creating and maintaining objects within the

ABAP Dictionary. The purpose of this chapter is to familiarise you with how objects are

created, stored, and used by the ABAP Dictionary.



1.01.4 Version 2.0



BC030_2.01.4

No Redundant Data Definitions

Functions of the ABAP Dictionary

Integration with the ABAPWorkbench

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Data Integrity

• The ABAP Dictionary:

– Enforces data integrity

– Manages data definitions without redundancy

– Is tightly integrated with the rest of the ABAP Workbench

• The ABAP Workbench supports the development and modification of client/server

applications written in ABAP. It is the integrated graphical development environment of

the R/3 System.

• The ABAP Workbench can be used to:

• Write ABAP code

•

Design screens• Create user interfaces

• Test applications for efficiency

• Check applications for errors

• Use predefined functions

• Access development objects

• Access database information



1.01.5 Version 2.0



BC030_2.01.5

Data Integrity

• Enforcing data integrity is the process of ensuring that data entered into the system is

logical, complete, and consistent.• When data integrity rules are defined in the ABAP Dictionary, the system automatically

prevents the entry of invalid data. Defining the data integrity rules at the dictionary level

means they only have to be defined once, rather than in each program that accesses that

data.

• The following are examples of data lacking integrity:

– A date field with a month value of 13

– An order assigned to a customer number that doesn’t exist

– An order not assigned to a customer



1.01.6 Version 2.0



BC030_2.01.6

No Redundant Data Definitions

• Managing data definitions without redundancy is the process of linking similar

information to the same data definition.• For example, a customer database is likely to contain a customer’s ID number in several

places. The ABAP Dictionary provides the capability of defining the characteristics of a

customer ID number in only one place. That central definition then can be used for each

instance of a customer ID number.



1.01.8 Version 2.0



BC030_2.01.8

Basic Objects of the ABAP Dictionary

Table CTable BTable A

DomainDomain

Data Element 2Data Element 2Data Element 1Data Element 1

• The basic objects of the ABAP Dictionary are tables, data elements,

and domains.• Tables are the structures that actually store the information that is in the database (i.e.,

customer information). Tables are composed of rows (called records) and columns

(called fields).

• Data elements and domains are used to describe the characteristics of fields.

• More information about these objects will be covered in future chapters.



1.01.9 Version 2.0



BC030_2.01.9

Database Utility

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Database

Utility

DatabaseDatabase

• The database utility is a program that provides the interface between the ABAP

Dictionary and the underlying database management system (DBMS). It allows you tocreate ABAP-defined objects such as tables and database views physically in the database.

It can be executed in foreground and background.

• Whenever you make a change to a dictionary object that affects the underlying database,

the database utility is activated. Usually it works silently behind the scenes, but

occasionally the database utility will prompt you for information. This occurs when an

error is encountered or when existing data must be converted.

• The database utility provides the interface to the DBMS by automatically generating the

Data Definition Language (DDL) that the DBMS understands.



1.01.10 Version 2.0



BC030_2.01.10

Summary

• The participants should be able to:

– Define the ABAP dictionary

– Describe the functions of the ABAP Dictionary

– Describe the basic objects of the ABAP

Dictionary

– Explain the how Database Utility interfaces with

the ABAP Dictionary and the underlying

database

• Summary

dictionary - chapter 01

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