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egolindano1-Visitor
1-Visitor
November 28, 2016
Solved

Auto increment values.

  • November 28, 2016
  • 2 replies
  • 4714 views

Hi everyone. Is there anyway to create an auto increment field in a datatable? if so, can you provide me an example? Thank You for your time.

Best answer by CarlesColl

Hi Autoincrements should never be implemented with a getRowCount, in any platform.

We implemented on ThingWorx using a LONG property on the DataTable Thing, and you just increment it, and use it's value, of course make it persistent, this way you will lock other threads entering on the property while you are updating it and you won't lose last increment . In order to reuse it, we did it on a ThingShape that we add on the DataTable that we wan't an autoincrement.

2 replies

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supandey5-Regular Member
5-Regular Member
November 28, 2016

Eddison, you can do this by calculating the rows in the data table something like this

// max number of rows fetched from the table in a pass

var params = {

  maxItems: undefined /* NUMBER */

};

// result: INFOTABLE

var result = Things["DataTableName"].GetDataTableEntries(params);

var finalResult= (result.getRowCount() +1);

But if you expect to have large number of entities you'd be better of using an RDBMS table to store that and not to mention that they have inbuilt feature to auto increment the values. Since using this method on a Data Table could affect the performance...

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egolindano1-VisitorAuthor
1-Visitor
November 28, 2016

I was thinking about that way, but It's not good, since values can be duplicated

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CarlesColl1-VisitorAnswer
1-Visitor
November 28, 2016

Hi Autoincrements should never be implemented with a getRowCount, in any platform.

We implemented on ThingWorx using a LONG property on the DataTable Thing, and you just increment it, and use it's value, of course make it persistent, this way you will lock other threads entering on the property while you are updating it and you won't lose last increment . In order to reuse it, we did it on a ThingShape that we add on the DataTable that we wan't an autoincrement.

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    egolindano1-VisitorAuthor
    1-Visitor
    November 28, 2016

    Thank You, Carles. That's a great idea.

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