Allow substitution parameters to be used in the SELECT and FROM clauses of the TableLookup Data Reference
As a user, I would like TableLookup Data Reference to be able to use substitution parameters to specify the column name(s) and table name for the SELECT and FROM fields respectively. This would allow for the use of attribute values like those from String Builder attributes to be used to identify the desired column(s) or table and facilitate the use of table lookup within Element Templates.
Our current development cycle does not include this request. We will update this idea if the status changes.
Guillaume Boue commented
Hello, is the status = "no status" ?
It seems this is ranked in the TOP 10 of PI Server UserVoice in #Votes.
Could we have a status regarding this request?
We are using a table lookup to help quickly assign many pi tags to the right attributes, but we have been cautioned not to have tables that get too big. Therefore we need to break the tables up into multiple different tables, and then update either the elements or templates to point to the right table. Which breaks up the streamlined nature of using templates.
The ability to specify the table with substitution parameters would make this much smoother.
Each OEM has its own braking list and sometimes it differs model to model, so we have different templates for each so we can reference the correct table. Substitution parameters to select which table to choose from would be very beneficial in reducing the number of templates we need to have and therefore improving manageability of our AF.
I would like to use a substitution parameter in the WHERE clause to reference one of a group of attributes in the template.
select mycolumn from mytable where table-ref-column = @template-ref-column%which -one%
%which-one% would contain a numeric value.
Is there a way to reference an array of "template-ref-column" to obtain the correct data from "mytable"?
This Feature would be Awesome. Please Make It Happen. Need it ASAP!
Unfortunately cannot vote multiple times, but new use case.
Using templated lookups, but still need to override individual lookups to use the correct result column.
Quite tricky currently, as one unwanted reset-to-template starts delivering faulty lookups...
Diego Curras commented
Here is another user case:
I would like TableLookup Data Reference to be able to use a reference to an attribute value (i.e @Attribute) to specify the column name(s) for the SELECT
Fabiano Batista commented
Here is another user case:
A customer has a federated PI System with several remote AF units, and one central AF showing the same content from each of those units. Each unit has the same set of templates and tables. The remote AF structures are supposed to be copied to the central unit via PI System Connector, each one appearing in the right branch of the central AF hierarchy. The central AF server has also the same set of templates and table names. Today, PI System connector cannot merge table data, but instead it replaces the existing central table by the content from the last unit which table was synchronized by PI System Connector.
As a solution, the tables at each unit could be renamed by appending a unique identifier (such as unit code). Then, the element template could be configured with a TABLE LOOKUP containing a substitution parameter in the FROM clause to allow pulling data from different tables (i.e., unit specific tables).
Some benefits of this solution:
- Less element templates needed (easier to maintain in a federated PI system environment)
- Better lookup performance (each branch on the central unit will be pointing to smaller tables, instead of pointing to a single big table)
Please do it ! It would help us a lot.
Jason Jian-Hao Lu commented
Here's an example from a TechSupport case:
Customer wants to create a Table Lookup attribute template that uses the value of a String Builder attribute which includes substitution parameters to select the Table Name associated with it's Parent Element.
For example, customer has a table named after each Element and they want to build out their Element hierarchy. They would want to do something like this to link the table lookup attributes to the desired table:
Table Name: 11D01 Stable
String Builder attribute: %Element%;" Stable";
Table Lookup Data Reference:
SELECT <column> FROM %@String Builder attribute% WHERE <condition>
The substitution paremters in the FROM clause would resolve to "11D01 Stable" as intended.