SRM_QUANTITY 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 "Proxy Structure (Generated)...." 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_SRM_QUANTITY TYPE SRM_QUANTITY.
The SRM_QUANTITY table consists of various fields, each holding specific information or linking keys about Proxy Structure (Generated).... data available in SAP. These include UNIT_CODE (Proxy Data Element (generated)...), VALUE (QUANTITY is the non-monetary numerical declaration of a quan)... 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. .