建立 materialized view

建立具體化檢視表。

深入探索

如需包含這個程式碼範例的詳細說明文件，請參閱下列內容：

程式碼範例

Go

在試行這個範例之前，請先按照 BigQuery 快速入門導覽課程：使用用戶端程式庫中的 Go 設定說明進行操作。詳情請參閱 BigQuery Go API 參考說明文件。

如要向 BigQuery 進行驗證，請設定應用程式預設憑證。 詳情請參閱「設定用戶端程式庫的驗證機制」。

import (
	"context"
	"fmt"

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

// createMaterializedView demonstrates generated a materialized view based on an existing
// base table.
func createMaterializedView(projectID, datasetID, baseTableID, viewID string) error {
	// projectID := "my-project-id"
	// datasetID := "mydatasetid"
	// baseTableID := "mytableid"
	// viewID := "myviewid"
	ctx := context.Background()

	client, err := bigquery.NewClient(ctx, projectID)
	if err != nil {
		return fmt.Errorf("bigquery.NewClient: %w", err)
	}
	defer client.Close()

	// Get an appropriately escaped table identifier suitable for use in a standard SQL query.
	tableStr, err := client.Dataset(datasetID).Table(baseTableID).Identifier(bigquery.StandardSQLID)
	if err != nil {
		return fmt.Errorf("couldn't construct identifier: %w", err)
	}

	metaData := &bigquery.TableMetadata{
		MaterializedView: &bigquery.MaterializedViewDefinition{
			Query: fmt.Sprintf(`SELECT MAX(TimestampField) AS TimestampField, StringField, 
					  MAX(BooleanField) AS BooleanField FROM %s GROUP BY StringField`, tableStr),
		}}

	viewRef := client.Dataset(datasetID).Table(viewID)
	if err := viewRef.Create(ctx, metaData); err != nil {
		return err
	}
	return nil
}

Java

在試行這個範例之前，請先按照 BigQuery 快速入門導覽課程：使用用戶端程式庫中的 Java 設定說明進行操作。詳情請參閱 BigQuery Java API 參考說明文件。

如要向 BigQuery 進行驗證，請設定應用程式預設憑證。 詳情請參閱「設定用戶端程式庫的驗證機制」。

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.TableId;
import com.google.cloud.bigquery.TableInfo;

// Sample to create materialized view
public class CreateMaterializedView {

  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 materializedViewName = "MY_MATERIALIZED_VIEW_NAME";
    String query =
        String.format(
            "SELECT MAX(TimestampField) AS TimestampField, StringField, "
                + "MAX(BooleanField) AS BooleanField "
                + "FROM %s.%s GROUP BY StringField",
            datasetName, tableName);
    createMaterializedView(datasetName, materializedViewName, query);
  }

  public static void createMaterializedView(
      String datasetName, String materializedViewName, String query) {
    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);

      MaterializedViewDefinition materializedViewDefinition =
          MaterializedViewDefinition.newBuilder(query).build();

      bigquery.create(TableInfo.of(tableId, materializedViewDefinition));
      System.out.println("Materialized view created successfully");
    } catch (BigQueryException e) {
      System.out.println("Materialized view was not created. \n" + e.toString());
    }
  }
}

Python

在試行這個範例之前，請先按照 BigQuery 快速入門導覽課程：使用用戶端程式庫中的 Python 設定說明進行操作。詳情請參閱 BigQuery Python API 參考說明文件。

如要向 BigQuery 進行驗證，請設定應用程式預設憑證。 詳情請參閱「設定用戶端程式庫的驗證機制」。

from google.cloud import bigquery

bigquery_client = bigquery.Client()

view_id = "my-project.my_dataset.my_materialized_view"
base_table_id = "my-project.my_dataset.my_base_table"
view = bigquery.Table(view_id)
view.mview_query = f"""
SELECT product_id, SUM(clicks) AS sum_clicks
FROM  `{base_table_id}`
GROUP BY 1
"""

# Make an API request to create the materialized view.
view = bigquery_client.create_table(view)
print(f"Created {view.table_type}: {str(view.reference)}")

Terraform

如要瞭解如何套用或移除 Terraform 設定，請參閱「基本 Terraform 指令」。 詳情請參閱 Terraform供應商參考說明文件。 

resource "google_bigquery_dataset" "default" {
  dataset_id                      = "mydataset"
  default_partition_expiration_ms = 2592000000  # 30 days
  default_table_expiration_ms     = 31536000000 # 365 days
  description                     = "dataset description"
  location                        = "US"
  max_time_travel_hours           = 96 # 4 days

  labels = {
    billing_group = "accounting",
    pii           = "sensitive"
  }
}

resource "google_bigquery_table" "default" {
  dataset_id          = google_bigquery_dataset.default.dataset_id
  table_id            = "my_materialized_view"
  deletion_protection = false # set to "true" in production

  materialized_view {
    query                            = "SELECT ID, description, date_created FROM `myproject.orders.items`"
    enable_refresh                   = "true"
    refresh_interval_ms              = 172800000 # 2 days
    allow_non_incremental_definition = "false"
  }

}

後續步驟

如要搜尋及篩選其他 Google Cloud 產品的程式碼範例，請參閱Google Cloud 範例瀏覽器。