Powerchart Keycolumn distinctions

Ignition
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1

I’m looking for some guidance on how the keycolum/keyvalue pairs communicate with the DB historian table. The following two instances work:

histprov:OBD_Log_Files:/table:flex_logs:/column:System_Mode

histprov:OBD_Log_Files:/table:flex_logs:/column:System_Mode:/keycolumn:MS_STATE:/keyvalue:4

However, for some reason the following path does not return any data:

histprov:OBD_Log_Files:/table:flex_logs:/column:System_Mode:/keycolumn:unit_id:/keyvalue:V30_TST

For reference is a screenshot of the DB table associated with the historian-

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Not sure if this is relevant, but the DB table’s structure itself requires a composite key using t_stamp, unit_id, and batch_id to avoid duplicates during file inserts.

An alternative would be pivoting to individual tables in the schema for each unit, but I’d rather not have an increasing number of tables at each unit deployment

2

Might be that the keyvalue is always interpreted as a string? So will never match any integers?

3

The instance that is using the integer as a keyvalue, used with keycolumn:MS_STATE does return data to the powerchart. It is the string V30_TST instance that is giving me problem.

Are you implying that keyvalue is expecting an integer?

4

Ah, missed that. Does the table column have space padding?

5

It does not - here is a snippet of the table parameters from MySQL. I have it defined as VARCHAR(7) which matches my value for V30_TST.

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6

I’ve also tested other key/value pairs that utilized strings and were successful. My thought was that it might be related to the DB having a composite key, but I briefly removed unit_id as a key

7

I'm out of ideas. Time for a support ticket.