AlterTableWithForeignKeyDeleteCascadeSample.java

/*
 * Copyright 2023 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.spanner;

// [START spanner_alter_table_with_foreign_key_delete_cascade]

import com.google.cloud.spanner.Spanner;
import com.google.cloud.spanner.SpannerOptions;
import com.google.cloud.spanner.admin.database.v1.DatabaseAdminClient;
import com.google.common.collect.ImmutableList;
import com.google.spanner.admin.database.v1.DatabaseName;

class AlterTableWithForeignKeyDeleteCascadeSample {

  static void alterForeignKeyDeleteCascadeConstraint() {
    // TODO(developer): Replace these variables before running the sample.
    String projectId = "my-project";
    String instanceId = "my-instance";
    String databaseId = "my-database";

    alterForeignKeyDeleteCascadeConstraint(projectId, instanceId, databaseId);
  }

  static void alterForeignKeyDeleteCascadeConstraint(
      String projectId, String instanceId, String databaseId) {
    try (Spanner spanner =
        SpannerOptions.newBuilder().setProjectId(projectId).build().getService();
        DatabaseAdminClient databaseAdminClient = spanner.createDatabaseAdminClient()) {
      databaseAdminClient.updateDatabaseDdlAsync(DatabaseName.of(projectId, instanceId,
              databaseId),
          ImmutableList.of(
              "ALTER TABLE ShoppingCarts\n"
                  + "              ADD CONSTRAINT FKShoppingCartsCustomerName\n"
                  + "              FOREIGN KEY (CustomerName)\n"
                  + "              REFERENCES Customers(CustomerName)\n"
                  + "              ON DELETE CASCADE\n"));
      System.out.printf(
          String.format(
              "Altered ShoppingCarts table with FKShoppingCartsCustomerName\n"
                  + "foreign key constraint on database %s on instance %s",
              databaseId, instanceId));
    }
  }
}
// [END spanner_alter_table_with_foreign_key_delete_cascade]