ATPHI 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 "ATP Server: definition of hierarchy" 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_ATPHI TYPE ATPHI.
The ATPHI table consists of various fields, each holding specific information or linking keys about ATP Server: definition of hierarchy data available in SAP. These include WERKS (Plant), SOBKZ (Special Stock Indicator), SSKEY (ATP: Key for special stock segment), RDMOD (ATP Server: read mode (individual or totals records))... 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. .