Tip: Exporting structures with more than 127 attributes to Excel

Tip: Exporting structures with more than 127 attributes to Excel

  

Symptoms:

When using the RecordListToExcel to export a structure with more than 127 attributes will generate the error message Too many fields defined..

A Typical error stack is like:


Message :[1] Too many fields defined.
Stack: at ssSLSRetail.Flows.FlowFrontOffice.ScrnProductLabels_Export.CommandWord(HeContext heContext)
at ssSLSRetail.Flows.FlowFrontOffice.ScrnProductLabels_Export.wt_Submitwidget142184_Click(Object sender, EventArgs e)
at System.Web.UI.WebControls.Button.OnClick(EventArgs e)
at System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument)
at System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument)
at System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData)
at System.Web.UI.Page.ProcessRequestMain()

Cause:

Parafrasing the Microsoft Article 199076:


"The Microsoft Jet database engine has an internal limit of 255 fields per query. As the Microsoft Jet database engine iterates through the records in an update query, it creates a field for the original value and a field for the updated value. When more than 127 fields are selected, it reaches the 255 field limit of a query."

This means that structures with more than 127 attributes will hit this 255 field limit in the Microsoft Jet database Engine and generate this error message.

Resolution:

There's no directly solution for this problem, because it's a limitation of the MIcrosoft Jet database Engine, which is used by OutSystems platform for exporting/importing data to/from excel.
However, it's possible to workaround this problem using at least two types of approaches:

1. Build a HTML webscreen table for your data and then convert to Excel, as throughly explained in the forum Topic Sample: Producing fully styled Excel reports
2. Generate a Comma Separated Values (CSV) file through text data types and a text output file

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Best Regards

Miguel Simões João

Hi all....Do you know if there is a fix for this problem already?

Best Regards,

Diogo C S Cordeiro