USUSER_SYS is a standard SAP Table which is used to store GUM: Assignment of User (Group) to System (Type) data in SAP systems, such as SAP R/3, S/4HANA, depending on the version and release level.
The USUSER_SYS table consists of various fields, each holding specific information or linking keys about GUM: Assignment of User (Group) to System (Type) data available in SAP. These include RELUSER (GUM: User or User Group), RELTYPE_U (GUM: Type of User or User Group), RELSYSTEM (GUM: System or System Type), RELTYPE_S (GUM: Type of System or System Type)... See below for full list along with technical details, documentation, text table, check tables, foreign key relationships, conversion routines, relevant tcodes and example ABAP select code etc. .