更新物化视图

使用 API 更改物化视图属性。

深入探索

如需查看包含此代码示例的详细文档，请参阅以下内容：

• 管理具体化视图

代码示例

Go

试用此示例之前，请按照 BigQuery 快速入门：使用客户端库中的 Go 设置说明进行操作。 如需了解详情，请参阅 BigQuery Go API 参考文档。

如需向 BigQuery 进行身份验证，请设置应用默认凭据。 如需了解详情，请参阅为客户端库设置身份验证。

import (
	"context"
	"fmt"
	"time"

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

// updateMaterializedView updates a materialized view by manipulating MV properties.
func updateMaterializedView(projectID, datasetID, viewID string) error {
	// projectID := "my-project-id"
	// datasetID := "mydataset"
	// viewID := "myview"
	ctx := context.Background()
	client, err := bigquery.NewClient(ctx, projectID)
	if err != nil {
		return fmt.Errorf("bigquery.NewClient: %w", err)
	}
	defer client.Close()

	// Retrieve current view metadata.
	viewRef := client.Dataset(datasetID).Table(viewID)
	meta, err := viewRef.Metadata(ctx)
	if err != nil {
		return fmt.Errorf("couldn't retrieve view metadata: %w", err)
	}

	if meta.MaterializedView == nil {
		return fmt.Errorf("provided view %q is not a materialized view", viewID)
	}

	// construct an updated MV definition.
	newMV := &bigquery.MaterializedViewDefinition{
		Query:           meta.MaterializedView.Query,
		EnableRefresh:   true,
		RefreshInterval: meta.MaterializedView.RefreshInterval + time.Minute,
	}

	// Issue the update to alter the view.
	_, err = viewRef.Update(ctx, bigquery.TableMetadataToUpdate{
		MaterializedView: newMV,
	}, meta.ETag)
	if err != nil {
		return fmt.Errorf("Update(): %w", err)
	}
	return nil
}

Java

试用此示例之前，请按照 BigQuery 快速入门：使用客户端库中的 Java 设置说明进行操作。 如需了解详情，请参阅 BigQuery Java API 参考文档。

如需向 BigQuery 进行身份验证，请设置应用默认凭据。 如需了解详情，请参阅为客户端库设置身份验证。

import com.google.cloud.bigquery.BigQuery;
import com.google.cloud.bigquery.BigQueryException;
import com.google.cloud.bigquery.BigQueryOptions;
import com.google.cloud.bigquery.MaterializedViewDefinition;
import com.google.cloud.bigquery.Table;
import com.google.cloud.bigquery.TableId;

// Sample to update materialized view
public class UpdateMaterializedView {

  public static void main(String[] args) {
    // TODO(developer): Replace these variables before running the sample.
    String datasetName = "MY_DATASET_NAME";
    String materializedViewName = "MY_MATERIALIZED_VIEW_NAME";
    updateMaterializedView(datasetName, materializedViewName);
  }

  public static void updateMaterializedView(String datasetName, String materializedViewName) {
    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.
      BigQuery bigquery = BigQueryOptions.getDefaultInstance().getService();

      TableId tableId = TableId.of(datasetName, materializedViewName);

      // Get existing materialized view
      Table table = bigquery.getTable(tableId);
      MaterializedViewDefinition materializedViewDefinition = table.getDefinition();
      // Update materialized view
      materializedViewDefinition
          .toBuilder()
          .setEnableRefresh(true)
          .setRefreshIntervalMs(1000L)
          .build();
      table.toBuilder().setDefinition(materializedViewDefinition).build().update();
      System.out.println("Materialized view updated successfully");
    } catch (BigQueryException e) {
      System.out.println("Materialized view was not updated. \n" + e.toString());
    }
  }
}

Python

试用此示例之前，请按照 BigQuery 快速入门：使用客户端库中的 Python 设置说明进行操作。 如需了解详情，请参阅 BigQuery Python API 参考文档。

如需向 BigQuery 进行身份验证，请设置应用默认凭据。 如需了解详情，请参阅为客户端库设置身份验证。

import datetime

from google.cloud import bigquery

bigquery_client = bigquery.Client()

view_id = "my-project.my_dataset.my_materialized_view"
view = bigquery.Table(view_id)
view.mview_enable_refresh = True
view.mview_refresh_interval = datetime.timedelta(hours=1)

# Make an API request to update the materialized view.
view = bigquery_client.update_table(
    view,
    # Pass in a list of any fields you need to modify.
    ["mview_enable_refresh", "mview_refresh_interval"],
)
print(f"Updated {view.table_type}: {str(view.reference)}")

后续步骤

如需搜索和过滤其他 Google Cloud 产品的代码示例，请参阅 Google Cloud 示例浏览器。