"Universal" Constrain --- Syntax

[Rich S]

Greets, all:

I'm trying to set up a part of a script where it constrains on a Primary Key to isolate a record, irrespective of its table, and I'm stuck on the syntax.

The set-up:

Variable: $_TableName = Get (LayoutTableName)

The Primary Key: They all have the same naming convention in all the tables: _kplt_TableNameID" . The value inside every Primary Key is set by  Get ( UUID ).

 

Where I'm getting hung up is the Set Field syntax; the script (so far) goes like this:

 

Enter Find Mode [Pause: Off]

Set Field [ Evaluate ( $_TableName & "::" & "_kplt__" & $_Tablename & "ID" ) ;  ????? ]

Set Error Capture [ON]

Constrain Found Set [  ]

 

What do I use for the ??????  Also, is there a more elegant way of doing the same thing by using the Find Matching Records command?

 

As always, thanks in advance for your help!

[comment]

 

14 minutes ago, WF7A said:

I'm trying to set up a part of a script where it constrains on a Primary Key to isolate a record

Do you mean you want to isolate the current record, so that it becomes the only record in the found set?

[Rich S]

Yup.

[comment]

First, have a look at this classic:
https://fmforums.com/topic/97497-constrain-to-current-record/?do=findComment&comment=443142

 

To do it the way you have started, you would need something like:

Set Variable [ $fieldName; Value:Get ( LayoutTableName ) & "::" & "_kplt__" & Get ( LayoutTableName ) & "ID" ] 
Set Variable [ $id; Value:GetField ( $fieldName ) ]
Enter Find Mode [ ]
Set Field By Name [ $fieldName; $id ]
Perform Find []

Note that the Evaluate() function is not needed for this. Also there is very little point in setting a variable to one of the Get() functions: most, if not all of them are just that: variables.

 

1 hour ago, WF7A said:

is there a more elegant way of doing the same thing by using the Find Matching Records command?

I don't think so, because Find Matching Records[] does not allow the use of a calculated field name.

[Rich S]

Ah! Thanks.

Just for the sake of (an) argument, say I wanted to constrain to a specific field but its contents could be anything (not empty); what would I replace "ID" with?

[Fitch]

The whole idea is predicated on you using a consistent naming convention so that all your primary keys take the form:

"_kplt__" & Get ( LayoutTableName ) & "ID"

I wouldn't think you'd use that convention for every field in the table, that would be weird. So you wouldn't replace "ID" -- you'd completely replace that whole string with whatever field name you want to use.