Database Design Theory

I have been tasked with creating a Data Warehouse.

Problem is that old storage vs reporting debate.

I have determined that the data that I will recieve and store will be like follows (simplified form) for expandability

KEY FldKEy FldData DateTime AuditTrail

Daily I will use this data based on use input process this data into the following format and say
if fldkey/ flddata open a cycle.
populate row with null close date
if fldkey/ flddata closes cycle
update row with date

If fldkey/ flddata changes a cutable value
update row

if fldkey/ flddata changes a cutable value (type 2 table)
insert a row into detail update value and obsolete previous row.


KEY DateStart DateEnd FLDDATA1 FLDDATE2 Op_Cl_IND HEADER Record

KEY EFFdate OBSDATE FLDdata3 FLDData4 Detail Records
KEY EFFdate OBSDATE FLDdata3 FLDData4
KEY EFFdate OBSDATE FLDdata3 FLDData4

Problem: FLDKey is a finite count however the max is undefined.

IS there any way to solve the problem of not being able to nail down users to tell you what they want to cut by. What I have been instructed by mgr (old IDMS) is that they wish to see all on the FldData and have the ability to cut by all of it. However the Flddata could be anything (cannot be indexed).

400,000,000 rows at least.

Do I need to nail the users down or am I am missing something.

Sorry if so cryptic

:(