Failed to convert the value in 'xxxx' property to 'System.String' type in Data Lake Connector

Question

Environment: Azure Synapse

I am developing a pipeline that has a lookup to SQL that is passing the values to GetMetaData.

When using @dataset.name of parameter in the dataset, it fails with "Failed to convert the value in name of parameter property to 'System.String' type. I can view the outputs of the lookup activity and it is correct. I can copy the value from the output and manually insert it into the connector and it works. Is there an issue with Microsoft or do I have GetMetaData activity incorrectly configured?

Answer 1

Hi Doreen Cecil ,

Welcome to Microsoft Q&A platform and thanks for posting your query here.

The expression '@activity('lookup1').output.value' would typically return an array as the output which you are further referring to in Get metadata activity for Filepath parameter.

Kindly try having a Foreach activity to iterate through the result of lookup and use Getmetadata activity inside foreach that could take the filepath one by one through looping .

Or, try using a particular value for filepath out of the output json , forexample '@activity('lookup1').output.value[1].<OutputJsonKey>' .

Kindly consider sharing the output of lookup activity for better help in implementation .

Hope it helps. Kindly accept the answer if it helped. Thankyou

Answer 2

This typically occurs when the expected data type does not align with the actual data type of the parameter being used.

To avoid type conversion errors, try to convert the value to a string within the pipeline expressions. You can use the string() function in Azure Data Factory to treat the value as a string.

https://stackoverflow.com/questions/73756515/cant-convert-table-value-to-string-in-adf