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Asked: 2026-05-20T14:30:02+00:00

I have struggled with this issue for several weeks. I have Googled it and

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I have struggled with this issue for several weeks. I have Googled it and have zero relevant results (which probably means I can’t figure out how to Google it – not that the answer isn’t out there!)

Assume four tables

Table 1 – templates 

Template 1...  
Template 2...  
Template 3...  
Template 4...

Table 2 – Periods 

Period 1...  
Period 2...  
Period 3...  
Period 4...

Table 3 – Type 

Type 1...  
Type 2...

Table 4 – TemplateMatrix

Contains the matrix for which templates are applicable to which period and type. Most of the templates are applicable to all periods except 1 and there are specific templates for that period. Rather than create a templateMatrix record for every template for every period, I create one record for each specific period template with that periodID

EX: 

PeriodID,   TypeID,  TemplateID  
1       ,   1     ,  1
2       ,   1     ,  2

and a record with a NULL for PeriodID for all other periods for their templates.

EX: 

PeriodID,   TypeId, TemplateID  
NULL    ,   1,      3  
NULL    ,   2,      4

There are actually about 40 Periods and about 8 Templates and 2 types.

What I need is a view that will give me all possible Template and Period combinations- those that are expressly defined and all others.

In other words, 

Period 1, Type 1, Template 1  
Period 2, Type 1, Template 2  
Period 3, Type 1, Template 3  
Period 3, Type 2, Template 4  
Period 4, Type 1, Template 3  
Period 4, Type 2, Template 4  
Period 5, Type 1, Template 3  
Period 5, Type 2, Template 4  
Period 6, Type 1, Template 3  
Period 6, Type 2, Template 4

Worst case scenario, I could add all possible records to the matrix; however, that doesn’t seem very normalized to me since the only difference between the bulk of the records would be the Period ID.

Any ideas? I really am at my wits end.

Thanks,
John

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1 Answer

  1. Editorial Team

    You’ve struggled for weeks with a problem that could be solved by simply storing important business data directly in a table. We’re talking about, at most, around 360 rows, right? Just insert the rows. Jeez.

    The root cause of your problem is that a) you’re trying to shoehorn two predicates into one table, and b) you’re hoping to redefine what NULL means.

    PeriodID,   TypeID,  TemplateID  
1       ,   1     ,  1
NULL    ,   1     ,  3

    You want the first row to mean something like this:

    Template [TemplateID] is used in
    period [PeriodID] for something of
    type [TypeID]

    But you want the second row to mean something like

    Template [TemplateID] is used in every
    period that hasn’t been identified by [PeriodID] in some other row
    for something of type [TypeID]

    Trying stuff like that will almost always lead to grief.

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