Note
Access to this page requires authorization. You can try signing in or changing directories.
Access to this page requires authorization. You can try changing directories.
Applies to: ✅ Azure Data Explorer
Alters an existing external table mapping. For more information, see Data mappings.
Note
External table mappings apply only to reading data from external tables, not for exporting data.
Syntax
.alter external table ExternalTableName mapping MappingName MappingInJsonFormat
Learn more about syntax conventions.
Parameters
| Name | Type | Required | Description |
|---|---|---|---|
| ExternalTableName | The name of the external table to which to assign the mapping. | ||
| MappingName | The name of the mapping. | ||
| MappingInJsonFormat | The mapping definition in JSON format. |
Returns
Returns a table containing the mapping name, mapping kind, and new mapping definition.
Example
.alter external table MyExternalTable mapping "Mapping1" '[{"Column": "rownumber", "Properties": {"Path": "$.rownumber"}}, {"Column": "rowguid", "Properties": {"Path": "$.rowguid"}}]'
Output
| Name | Kind | Mapping |
|---|---|---|
| mapping1 | JSON | [{"ColumnName":"rownumber","Properties":{"Path":"$.rownumber"}},{"ColumnName":"rowguid","Properties":{"Path":"$.rowguid"}}] |