Update a table's description.

## Explore further


For detailed documentation that includes this code sample, see the following:

- [Manage logical views](https://docs.cloud.google.com/bigquery/docs/managing-views)
- [Manage tables](https://docs.cloud.google.com/bigquery/docs/managing-tables)

## Code sample

### Go


Before trying this sample, follow the Go setup instructions in the
[BigQuery quickstart using
client libraries](https://docs.cloud.google.com/bigquery/docs/quickstarts/quickstart-client-libraries).


For more information, see the
[BigQuery Go API
reference documentation](https://godoc.org/cloud.google.com/go/bigquery).


To authenticate to BigQuery, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/bigquery/docs/authentication#client-libs).

    import (
    	"context"
    	"fmt"

    	"cloud.google.com/go/bigquery"
    )

    // updateTableDescription demonstrates how to fetch a table's metadata and updates the Description metadata.
    func updateTableDescription(projectID, datasetID, tableID string) error {
    	// projectID := "my-project-id"
    	// datasetID := "mydataset"
    	// tableID := "mytable"
    	ctx := context.Background()
    	client, err := bigquery.NewClient(ctx, projectID)
    	if err != nil {
    		return fmt.Errorf("bigquery.NewClient: %w", err)
    	}
    	defer client.Close()

    	tableRef := client.Dataset(datasetID).Table(tableID)
    	meta, err := tableRef.Metadata(ctx)
    	if err != nil {
    		return err
    	}
    	update := bigquery.https://docs.cloud.google.com/go/docs/reference/cloud.google.com/go/bigquery/latest/index.html#cloud_google_com_go_bigquery_TableMetadataToUpdate{
    		Description: "Updated description.",
    	}
    	if _, err = tableRef.Update(ctx, update, meta.ETag); err != nil {
    		return err
    	}
    	return nil
    }

### Java


Before trying this sample, follow the Java setup instructions in the
[BigQuery quickstart using
client libraries](https://docs.cloud.google.com/bigquery/docs/quickstarts/quickstart-client-libraries).


For more information, see the
[BigQuery Java API
reference documentation](https://docs.cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/overview).


To authenticate to BigQuery, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/bigquery/docs/authentication#client-libs).

    import com.google.cloud.bigquery.https://docs.cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/com.google.cloud.bigquery.BigQuery.html;
    import com.google.cloud.bigquery.https://docs.cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/com.google.cloud.bigquery.BigQueryException.html;
    import com.google.cloud.bigquery.https://docs.cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/com.google.cloud.bigquery.BigQueryOptions.html;
    import com.google.cloud.bigquery.https://docs.cloud.google.com/java/docs/reference/google-cloud-biglake/latest/com.google.cloud.bigquery.biglake.v1.Table.html;

    public class UpdateTableDescription {

      public static void main(String[] args) {
        // TODO(developer): Replace these variables before running the sample.
        String datasetName = "MY_DATASET_NAME";
        String tableName = "MY_TABLE_NAME";
        String newDescription = "this is the new table description";
        updateTableDescription(datasetName, tableName, newDescription);
      }

      public static void updateTableDescription(
          String datasetName, String tableName, String newDescription) {
        try {
          // Initialize client that will be used to send requests. This client only needs to be created
          // once, and can be reused for multiple requests.
          https://docs.cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/com.google.cloud.bigquery.BigQuery.html bigquery = https://docs.cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/com.google.cloud.bigquery.BigQueryOptions.html.getDefaultInstance().getService();

          https://docs.cloud.google.com/java/docs/reference/google-cloud-biglake/latest/com.google.cloud.bigquery.biglake.v1.Table.html table = bigquery.https://docs.cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/com.google.cloud.bigquery.BigQuery.html#com_google_cloud_bigquery_BigQuery_getTable_com_google_cloud_bigquery_TableId_com_google_cloud_bigquery_BigQuery_TableOption____(datasetName, tableName);
          bigquery.https://docs.cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/com.google.cloud.bigquery.BigQuery.html#com_google_cloud_bigquery_BigQuery_update_com_google_cloud_bigquery_DatasetInfo_com_google_cloud_bigquery_BigQuery_DatasetOption____(table.toBuilder().setDescription(newDescription).build());
          System.out.println("Table description updated successfully to " + newDescription);
        } catch (https://docs.cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/com.google.cloud.bigquery.BigQueryException.html e) {
          System.out.println("Table description was not updated \n" + e.toString());
        }
      }
    }

### Python


Before trying this sample, follow the Python setup instructions in the
[BigQuery quickstart using
client libraries](https://docs.cloud.google.com/bigquery/docs/quickstarts/quickstart-client-libraries).


For more information, see the
[BigQuery Python API
reference documentation](https://docs.cloud.google.com/python/docs/reference/bigquery/latest).


To authenticate to BigQuery, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/bigquery/docs/authentication#client-libs).

    # from google.cloud import bigquery
    # client = bigquery.Client()
    # project = client.project
    # dataset_ref = bigquery.DatasetReference(project, dataset_id)
    # table_ref = dataset_ref.table('my_table')
    # table = client.get_table(table_ref)  # API request

    assert table.description == "Original description."
    table.description = "Updated description."

    table = client.update_table(table, ["description"])  # API request

    assert table.description == "Updated description."

## What's next


To search and filter code samples for other Google Cloud products, see the
[Google Cloud sample browser](https://docs.cloud.google.com/docs/samples?product=bigquery).