exasol · pj-spoelders · Dec 17, 2024
diff --git a/README.md b/README.md
@@ -42,7 +42,7 @@ The main new feature is native query support. For a brief overview see the [cust
 
 ![alt text](https://github.com/EXASOL/powerbi-exasol/blob/master/screenshots/Example_Dashboard_Billion_Rows.PNG )
 
-## Using DSNs and Kerberos authentication
+## Using DSNs, enabling ODBC logging and Kerberos authentication
 
 Please see the [user guide](doc/user_guide/user_guide.md)
 
@@ -51,14 +51,16 @@ Please see the [user guide](doc/user_guide/user_guide.md)
 Custom queries using `Value.NativeQuery` are supported starting from connector version 1.1.0.
 
 An example (using the Advanced Editor):
-```
+```mashup
 let
     Source = Exasol.Database("<hostname,ip address or dsn>", "Yes"),
     CustomQuery = Value.NativeQuery( Source, "SELECT * FROM SCHEMANAME.TABLENAME")
 in
     CustomQuery
 ```
 
+General advice: Microsoft doesn’t recommend using SQL queries as the source of tables with Value.NativeQuery/[EnableFolding=true]. Turning these queries into views and referencing the views in your semantic model is probably the better move if possible.
+
 ## How To use the Exasol Power BI Connector with the On-premises data gateway
 
 The Exasol connector was tested successfully with the On-premises data gateway version 3000.8.452 (August 2019) and also supports Direct Query. 
@@ -67,8 +69,42 @@ The Exasol connector was tested successfully with the On-premises data gateway v
 
 Also make sure you install the latest Exasol ODBC driver and Visual C++ Redistributable on the machine/VM where you install the data gateway, just as you would when you intend to use the connector for Power BI Desktop, for more information see section [Prerequisites](#prerequisites).
 
+## Articles on Power BI + Exasol
+
+[Working with Exasol geospatial data in Power BI](https://exasol.my.site.com/s/article/Working-with-Exasol-geospatial-data-in-Power-BI?language=en_US)
+
+## FAQ / Frequent issues
+
+### "OLE DB or ODBC error: [Expression.Error] We couldn’t fold the expression to the data source. Please try a simpler expression"
+
+Please see: https://blog.crossjoin.co.uk/2022/05/08/understanding-the-we-couldnt-fold-the-expression-to-the-data-source-error-in-power-bi/
+
+### Issues with TIMESTAMP WITH LOCAL TIME ZONE data type
+
+This is PowerBI specific:
+Types PowerBI can't make sense of or map implicitly get ‘delivered’ as ‘Type.Binary’ in PowerBI.
+
+The easiest workaround in this case would be to create a view in the Exasol DB itself that contains all the columns you need and to convert this problematic ‘TIMESTAMP WITH LOCAL TIME ZONE' column to a calculated ‘TIMESTAMP' column that’s also part of the view. 
+
+A 'TIMESTAMP’ column gets correctly read out by PowerBI.
+
+The SQL command to create this view and do the conversion would look like this:
+```sql
+CREATE VIEW YOURSCHEMA.WORKAROUNDVIEW as select … , CONVERT( TIMESTAMP , TSLTZ) AS DTCONVERTED from YOURSCHEMA.YOURTABLE;
+```
+Where TSLTZ is the original ‘TIMESTAMP WITH LOCAL TIME ZONE' column and DTCONVERTED is the calculated & converted 'TIMESTAMP' column .
+
+You can then query this view in PowerBI without any further conversion steps needed for the new timestamp column.
+
+### "OLE DB or ODBC error: [Expression.Error] Local evaluation of Table.Join or Table.NestedJoin with key equality comparers is not supported"
+
+Usually this issue is caused by a faulty DAX expression or an unexpected value being returned by a DAX expression. 
+
+An example:
+
+This issue can, for example, occur when using RLS in PowerBI. If the DAX expression for a certain role does not return a list of valid values, but instead returns a value like 'false' it might break the visuals and underlying query when filtering.
 
 ## Additional information
 
 * [Changelog](doc/changes/changelog.md)
-
+* [Developer guide](doc/developer_guide/developer_guide.md)
diff --git a/doc/developer_guide/developer_guide.md b/doc/developer_guide/developer_guide.md
@@ -0,0 +1,64 @@
+# Developer guide
+
+## SDKs
+
+### PowerQuery SDK for Visual Studio 2019
+
+DEPRECATED ( https://github.com/microsoft/DataConnectors)
+
+Please use PowerQuery SDK for Visual Studio Code instead
+
+### PowerQuery SDK for Visual Studio Code
+
+Install extension via VS code 
+
+Repo of SDK + issues section: 
+https://github.com/microsoft/vscode-powerquery-sdk 
+
+### Develop a connector using the PowerQuery SDK for Visual Studio Code
+
+https://learn.microsoft.com/en-us/power-query/install-sdk
+
+#### Building 
+
+Select Terminal > "Run build task ..." > And then pick one of 2 options
+- "Build connector project using MakePQX (newer)
+- "MSBuild" (legacy)
+
+A .mez file will be created if all goes well.
+
+#### Testing
+
+TBC
+
+#### Testing changes in PowerBI locally
+
+You can install your newly created .mez file in:
+
+C:\Users\<username>>\Documents\Power BI Desktop\Custom Connectors
+
+You'll also need to enable some settings in PowerBI Desktop locally:
+https://learn.microsoft.com/en-us/power-bi/connect-data/desktop-connector-extensibility#custom-connectors
+
+If you go to Get Data > and look for Exasol you'll see 'Exasol (Custom)' if the extension's loaded correctly.
+
+
+If you wish to run a custom version of the connector on the PowerBI service you'll also need to put the connector in place for the On-Prem Data Gateway.
+
+## Submission for certification
+
+The Connector Certification portal will be decommissioned by the end of this calendar year (https://connectorcertification.azurewebsites.net/). Effective December 16, 2024, all connector certification submissions should be made via email to [email protected].
+
+## Microsoft Support
+
+### Official Support
+
+https://admin.powerplatform.microsoft.com/support
+
+### PowerQuery SDK board
+
+https://github.com/microsoft/vscode-powerquery-sdk
+
+
+
+