BDT_INSTANCE is a standard SAP Structure so does not store data like a database table does. It can be used to define the fields of other actual tables or to process "Data for BDT Instance" Information within sap ABAP programs. This is done by declaring abap internal tables, work areas or database tables based on this Structure. These can then be used to store and process the required data appropriately. i.e. DATA: wa_BDT_INSTANCE TYPE BDT_INSTANCE.
The BDT_INSTANCE table consists of various fields, each holding specific information or linking keys about Data for BDT Instance data available in SAP. These include HANDLE_PRIM (ID of a BDT Instance), HANDLE_SUPER (ID of a BDT Instance), N_SEC_INSTANCES (Natural Number), N_SUB_INSTANCES (Natural Number)... 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. .