SE11

SE11 is the SAP transaction code used to access the ABAP Dictionary, the central repository for all data definitions in an SAP system. It provides a standard, centralized way to define data types, tables, and other objects that govern how data is stored, validated, and transferred between programs and applications. The dictionary enforces data integrity and consistency across ABAP programs, reports, interfaces, and user exits.

Core dictionary objects include domains (technical attributes such as data type, length, optional value ranges) and data elements (semantic meaning tied to a domain). Tables, including transparent tables, and legacy pooled or cluster tables, store actual data; structures and table types support composite data definitions; and views (database, projection, and help views) enable logical representations. The dictionary also supports search helps, check tables for value validation, and foreign key relationships to enforce referential integrity. In addition, it provides type groups, domain values, and documentation within objects.

Lifecycle and usage: when dictionary objects are defined, they are activated and stored in the system; changes are captured in transport requests for movement between systems. Important table properties like delivery class, data class, size category, buffering, and logging are defined in the technical settings. SE11 is commonly used by developers and admins; SE12 is typically used to display dictionary objects rather than edit them.