MDST_MISSING_KEY 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 "Structure for Missing IDs in Key Mapping" 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_MDST_MISSING_KEY TYPE MDST_MISSING_KEY.
The MDST_MISSING_KEY table consists of various fields, each holding specific information or linking keys about Structure for Missing IDs in Key Mapping data available in SAP. These include SCHEME_ID (UKM: CCT: Identifier Schema ID)... 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. .