Abap data dictionary

DATA
Data is information that has been translated into a
form that is efficient for movement or processing.
Metadata is data that describes other data.
METADATA

What is Data Dictionary?
• Data Dictionary is a central source of
information for the data in a information
management system.
• Its main function is to support the creation and
management of data definitions (or
"metadata").

Data Types
• Variables are nothing but reserved memory
locations to store values.
• You may like to store information of various
data types like character, integer, floating
point, etc.
• Based on the data type of a variable, the
operating system allocates memory and
decides what can be stored in the reserved
memory.

Elementary Data Types
• Byte
• Numeric
• Character-like
http://www.byte-notes.com/bit-byte-nibble-kilobyte

• Domains
• Data elements
• Tables and structures
ABAP Dictionary 3 levels

Domains
• Describes the technical characteristics of a table
field
• Specifies a value range which describes allowed
data values for the fields
• Fields referring to the same domain (via the data
elements assigned to them) are changed when a
change is made to the domain
• Ensures consistency

Data Elements
• Describes the role played by a field in a technical
context
• Fields of same semantic meaning can refer to the
same data element
• Contains the field information

Tables
• Represent the Database Tables where data
actually resides.
• Tables can be defined independently of the
database in the ABAP Dictionary.
• The fields of the table are defined with their
(database-independent) SAP ABAP data types
and lengths.

Structures
• Are record declarations that do NOT correspond to
a Database Table.
• Just like user-defined data type.
• Defined like a table and can then be addressed
from ABAP programs.
• Structures contain data only during the runtime of
a program.

Aggregated Objects Of ABAP Dictionary
• Aggregated means consisting of several
components.
• In the ABAP Dictionary, aggregated objects are
objects which come from several different
transparent tables.
• Views
• Search Help
• Lock Objects

Views
• Views in SAP _ ABAP are used to summarize data
which is distributed among several tables
• The data of a view is not actually physically
stored. The data of a view is instead derived from
one or more other tables
• It is tailored to the needs of a specific application

Search Help
• A Search help is a tool to help you search for data
records in the system
• An efficient and user-friendly search assists users
where the key of a record is unknown

Lock Objects
• Simultaneous accessing of the same data record by two users
in the SAP system is synchronized by a lock mechanism.
• Locks are set and released by calling certain function modules.
These function modules are generated automatically from the
definition of so-called lock objects in the ABAP/4 Dictionary
• Function modules :
Enqueue_<obj name> - to lock the table
dequeue_<obj name> - to release the lock

T-CODES
• SE11
• SE16N
• SE38

DECLARING A VARIABLE
Syntax:
DATA VARIABLE_NAME TYPE DATA_TYPE.
EXAMPLE:
DATA LV_VAR1 TYPE I.
DECLARING A INTERNAL TABLE
Syntax:
DATA INTERNAL_TABLE_NAME TYPE STANDARD TABLE OF TABLE_NAME.
EXAMPLE:
DATA LT_VBAK TYPE STANDARD TABLE OF VBAK.

DECLARING A STRUCTURE
Syntax:
TYPES BEGIN OF TYPE_NAME,
VARIABLE_NAME TYPE VARIABLE_TYPE,
VARIABLE_NAME1 TYPE VARIABLE_TYPE,
END OF TYPE_NAME.
EXAMPLE:
TYPES BEGIN OF TY_VBAK,
VBELN TYPE VBELN_VA,
NETWR TYPE NETWR,
END OF TY_VBAK.

Abap data dictionary

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