ABAPer Notes: The Central Repository of SAP, DATA DICTIONARY

ABAP Dictionary is a major tool of ABAP workbench which acts as a central repository for data definitions in SAP System. Hence, any new of modified information will be automatically provided for all system components to ensure the integrity, consistency, and security of the data. Having said that, it is just an interface as there is a real database which stores the data like DB2, MS SQL, Oracle, and even HANA.

The Object types in ABAP Dictionary are:

Tables: This is a table just like the one in a typical Relational Database Management System

View: This is a logical view of more than one table like the a Relational Database View do

Data Types: These are basic global data types, but very important as they determine the types of the data used by lots of programs. The data types includes:

Data element: Data element describes an individual fields in a form of elementary types. It tells the semantic attributes of a field like the field length, the number of decimal places, and even screen information like field help/explanatory text). However, the technical characteristics of the field such as data type (INT2, CURR, QUAN, CHAR, STRING), output characteristics, and value range in a field are defined in a domain.

Structure: Structure is a sequence of any other data types that can be used in the making of a workarea or even an internal table.

Table types: Just like a structure, but it is only for an internal table.

Lock objects: Objects that synchronize access to the same data by more than one user/program. Hence, it avoid the inconsistency when data is being maintained in the database. Domain: This is the technical type of a field which is used by a group of data elements as discussed before.

To summarize this, you can thinking the data types in this way:

Domain --> Data Elements --> Structure --> Table Type --> Table --> View