Data Dictionary (DDIC)

The Data Dictionary (DDIC) in SAP ABAP provides a central repository for managing data objects in an application. There are seven main types of DDIC objects that can be created and maintained in the Data Dictionary:

1. Database Tables.
2. Views.
3. Data Type ( data elements, structures, table types)
4. Type Groups.
5. Domain.
6. Search Helps.
7. Lock objects.

Tables: Tables are the most common type of DDIC object and are used to store data in a structured format. Each table has a defined structure, including the fields that make up the table and their data types. Tables can be created in the Data Dictionary using the Table Maintenance Generator (TMG), which provides a graphical interface for defining the table structure.

Views: Views are virtual tables that are based on one or more physical tables. Views are used to provide a simplified or filtered view of the data in a table. This can be useful for reporting or analysis, as it allows users to easily access and view the data they need.

Data type: It is a reusable definition of a data element that defines the technical attributes of the data, such as the data type, length, and decimal places. Data types are used to ensure consistency across the application and can be used in multiple places throughout the application.

The creation of a data type involves defining a name for the type and specifying its technical attributes, such as its data type, length, and decimal places. Data types can also include other attributes, such as currency and units of measurement.

Data types can be used in many DDIC objects, such as tables, structures, and domains. For example, a table may have fields that are defined using a specific data type. This allows the table to have consistent data types across its fields, making it easier to maintain and query the data.

1.  Data Elements: A data element is a reusable definition of a data type and its attributes. It consists of a name, a data type, and other attributes such as length and decimal places. Data elements are used to ensure consistency across the application.
2. Structure: is a complex data type that represents a collection of related fields or data elements grouped together under a single name. Structures are defined as a collection of components, each with a name and a data type, and are used to organize data in a logical manner. They can be used to define the structure of other DDIC objects, making it easier to maintain and query the data.
   
   
3. Table types can be used to define the structure of database tables or internal tables. For database tables, the table type defines the structure of the table and the fields that it can contain. For internal tables, the table type is used to define the structure of the table in memory, which is used to store data temporarily during program execution.

Type Groups: These are a way to group together related data types into a single, reusable object. They are often used in conjunction with domains, which are a set of technical attributes for a particular type of data, to provide a high degree of flexibility and consistency in data modeling.

Domains: Domains are used to define the values that a field can take on. A domain defines the technical attributes of a data element, such as the length and data type. Domains can be reused in multiple data elements, allowing for consistency and easier maintenance.

Search Helps: A search help is a tool that is used to provide a list of possible values for a field. This can be used to help users enter data more accurately, and it can also help to ensure data consistency across the application. Search helps can be defined for individual fields or for entire tables.

Lock Objects: Lock objects are used to manage database locks, which are used to ensure that data is not changed by multiple users simultaneously. A lock object defines the fields that are used to create a lock, as well as the type of lock that is used.