Add a second t_stamp to a dataset is failing

Ignition
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1

I’m trying to show both the epoch and local standard time next to each other from the output of a system.tag.queryTagHistory result.

The function call works fine, I’m putting the result on a custom value in the root of a page. Then I added a script transform to duplicate the t_stamp as t_stamp_readable and tried to add it as a java.util.timestamp but when I try to add the column to a dataset, it throws an error that I cant add a timestamp to a dataset.

Am I doing something wrong or should I try to add it as a string or something else? Any suggestions? Thanks!

2

Show the error(s) you are getting here. Post either your code or an example of the code you are using to attempt to add a column to the dataset. Make sure to post it as pre-formatted text, see Wiki - how to post code on this forum .

3

Line 9 is the return and the error is with java.sql.timestamp. Changing the type to str and java.util.date threw errors too. date couldn’t be coerced to a string and cant put a java.sql.timestamp into a java.util.date respectively. Thanks!

CODE:

def transform(self, value, quality, timestamp):
	import java.sql.Timestamp
	
	newColumneData = []
	for row in range(value.getRowCount()):
		tstamp_new = value.getValueAt(row, 't_stamp')
		newColumneData.append(tstamp_new)
	
	return system.dataset.addColumn(value, 0, newColumneData, 't_stamp_readable', java.sql.Timestamp)

ERROR:

Error_ScriptEval(“Traceback (most recent call last): File ““, line 9, in transform TypeError: Cant put element of type timestamp in dataset. “)

4

If you must manipulate time zone display yourself, you will suffer with java.util.Date and its subclasses (which includes java.sql.Timestamp) because they are zone-less objects. They parse and stringify in the JVM's default time zone, and you cannot use datetime arithmetic to correct this (produces subtle bugs).

Instead, create a java.time.Instant, and then a ZonedDateTime in the desired zone to print. That can be stringified reliably. (Use a date/time formatter for precise control.)

5

You will need to use the Dataset Builder. Which will allow you to specify the types for the columns.

6

Thanks for the input, do you recommend a different way to display the same date twice from the queryTagHistory function? I’m not married to the idea of adding it twice if there is a better way, thanks again!

7

Adding another column to the source data is reasonable, but it should be a string produced from a ZonedDateTime, not another date object. Objects that aren't native JSON don't transfer to the front-end well.

If displaying in a Perspective table, you might avoid adding the raw data column by using a column render view that takes the one column and display both forms. (This will really only be helpful for large virtualized tables.)

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8

Is a column render view a sub view or something different? Thanks!

9

See Embedding a view in a table-cell.

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