COMT_IL_UPDDATA 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 "Application Buffer for Relationships" 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_COMT_IL_UPDDATA TYPE COMT_IL_UPDDATA.
The COMT_IL_UPDDATA table consists of various fields, each holding specific information or linking keys about Application Buffer for Relationships data available in SAP. These include ILGUID (Internal, Unique ID of a Relationship), VALID_TO (Valid To (Time Stamp)), SOURCEGUID (Internal ID for Source in a Relationship), DESTINGUID (Internal ID for Destination in a Relationship)... 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. .