Specifies the file that the provider uses to determine the schema when aggregating multiple files into a single result set.

Data Type

string

Default Value

""

Remarks

This property applies when AggregateFiles is set to True. It defines which file the add-in reads to discover column names and data types for the aggregated table.

This property is useful when one file serves as the reference for schema discovery across multiple input files.

The path that you specify is resolved as follows:

• Relative path: resolved relative to the directory of the connection URI (the folder being aggregated).
• Absolute local path: a local path that starts with /, \, or a drive letter followed by a separator (for example, C:\ or C:/), optionally prefixed with file://, is always allowed, even when the connection points to cloud storage. In this case, the add-in reads the schema from the local file system while the data is read from the configured storage. Drive-relative values such as C: or C:dev are not treated as absolute paths.
• Absolute URI with a scheme: an absolute URI that includes a scheme (for example, s3://, gs://, or azureblob://) must point to the same storage as the connection. If its scheme does not match the connection's storage type, the connection fails with a configuration error.