ESH_S_IF_RELATION_FIELDS 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 "Relation fields" 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_ESH_S_IF_RELATION_FIELDS TYPE ESH_S_IF_RELATION_FIELDS.
The ESH_S_IF_RELATION_FIELDS table consists of various fields, each holding specific information or linking keys about Relation fields data available in SAP. These include PARENT_FIELD_ID (Node Field)... 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. .