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DatabaseOperations.java
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/
DatabaseOperations.java
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/*
* Copyright 2022 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;
import com.google.cloud.spanner.Database;
import com.google.cloud.spanner.DatabaseAdminClient;
import com.google.cloud.spanner.DatabaseClient;
import com.google.cloud.spanner.KeySet;
import com.google.cloud.spanner.Mutation;
import com.google.cloud.spanner.ResultSet;
import com.google.cloud.spanner.Statement;
import com.google.common.collect.ImmutableList;
import java.util.Collections;
import java.util.List;
/** Helper methods to manage Spanner Databases. */
public class DatabaseOperations {
private static final List<String> DDL_STATEMENTS =
ImmutableList.of(
"CREATE TABLE Singers (SingerId INT64 NOT NULL, FirstName "
+ "STRING(1024), LastName STRING(1024)) PRIMARY KEY (SingerId)");
static void createDatabase(
DatabaseAdminClient databaseAdminClient, String instanceId, String databaseId) {
if (databaseExists(databaseAdminClient, instanceId, databaseId)) {
databaseAdminClient.dropDatabase(instanceId, databaseId);
}
databaseAdminClient.createDatabase(instanceId, databaseId, DDL_STATEMENTS);
}
static boolean databaseExists(
DatabaseAdminClient databaseAdminClient, String instanceId, String databaseId) {
for (Database database : databaseAdminClient.listDatabases(instanceId).iterateAll()) {
if (databaseId.equals(database.getId().getDatabase())) {
return true;
}
}
return false;
}
static void insertUsingDml(DatabaseClient dbClient) {
dbClient
.readWriteTransaction()
.run(
transaction -> {
String sql =
"INSERT INTO Singers (SingerId, FirstName, LastName) "
+ " VALUES (10, 'Virginia', 'Watson')";
transaction.executeUpdate(Statement.of(sql));
return null;
});
}
static void insertUsingMutation(DatabaseClient dbClient) {
Mutation mutation =
Mutation.newInsertBuilder("Singers")
.set("SingerId")
.to(12)
.set("FirstName")
.to("Bob")
.set("LastName")
.to("Loblaw")
.build();
dbClient.write(Collections.singletonList(mutation));
}
static ResultSet performRead(DatabaseClient dbClient) {
return dbClient.singleUse().executeQuery(Statement.of("SELECT * FROM Singers"));
}
static void deleteDatabase(DatabaseClient dbClient) {
dbClient.write(Collections.singletonList(Mutation.delete("Singers", KeySet.all())));
System.out.println("Records deleted.");
}
}