여러 작업을 그룹으로 커밋할 필요가 없는 경우 트랜잭션을 기본 동작인 자동 커밋 모드에서 사용할 수 있습니다. 다음 코드 예시에서는 자동 커밋 모드에서 트랜잭션을 사용하여 Singers 테이블에 행을 추가합니다.
import java.math.BigDecimal;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.sql.Types;
import java.util.Arrays;
import java.util.List;
class InsertDataExample {
// Class to contain singer sample data.
static class Singer {
final long singerId;
final String firstName;
final String lastName;
final BigDecimal revenues;
Singer(long singerId, String firstName, String lastName, BigDecimal revenues) {
this.singerId = singerId;
this.firstName = firstName;
this.lastName = lastName;
this.revenues = revenues;
}
}
static final List<Singer> SINGERS =
Arrays.asList(
new Singer(10, "Marc", "Richards", new BigDecimal("104100.00")),
new Singer(20, "Catalina", "Smith", new BigDecimal("9880.99")),
new Singer(30, "Alice", "Trentor", new BigDecimal("300183")),
new Singer(40, "Lea", "Martin", new BigDecimal("20118.12")),
new Singer(50, "David", "Lomond", new BigDecimal("311399.26")));
static void insertData() throws SQLException {
// TODO(developer): Replace these variables before running the sample.
String projectId = "my-project";
String instanceId = "my-instance";
String databaseId = "my-database";
insertData(projectId, instanceId, databaseId);
}
static void insertData(String projectId, String instanceId, String databaseId)
throws SQLException {
String connectionUrl =
String.format(
"jdbc:cloudspanner:/projects/%s/instances/%s/databases/%s",
projectId, instanceId, databaseId);
try (Connection connection = DriverManager.getConnection(connectionUrl)) {
try (PreparedStatement ps =
connection.prepareStatement(
"INSERT INTO Singers\n"
+ "(SingerId, FirstName, LastName, SingerInfo, Revenues)\n"
+ "VALUES\n"
+ "(?, ?, ?, ?, ?)")) {
for (Singer singer : SINGERS) {
ps.setLong(1, singer.singerId);
ps.setString(2, singer.firstName);
ps.setString(3, singer.lastName);
ps.setNull(4, Types.BINARY);
ps.setBigDecimal(5, singer.revenues);
ps.addBatch();
}
int[] updateCounts = ps.executeBatch();
System.out.printf("Insert counts: %s%n", Arrays.toString(updateCounts));
}
}
}
}
그룹으로 여러 작업이 커밋되는 방식 제어
Spanner에서 여러 작업을 그룹으로 함께 커밋할지 여부를 제어하려면 자동 커밋 모드를 중지하면 됩니다. 다음 코드 예시에서는 connection.setAutoCommit(false) 및 connection.commit()을 사용하여 Singers 테이블에 행을 추가합니다.
import com.google.common.collect.ImmutableList;
import java.math.BigDecimal;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.Arrays;
class BatchDmlExample {
static class Singer {
final long singerId;
final String firstName;
final String lastName;
final BigDecimal revenues;
Singer(long singerId, String firstName, String lastName, BigDecimal revenues) {
this.singerId = singerId;
this.firstName = firstName;
this.lastName = lastName;
this.revenues = revenues;
}
}
static void batchDml() throws SQLException {
// TODO(developer): Replace these variables before running the sample.
String projectId = "my-project";
String instanceId = "my-instance";
String databaseId = "my-database";
batchDml(projectId, instanceId, databaseId);
}
// This example shows how to execute a batch of DML statements with the JDBC driver.
static void batchDml(String projectId, String instanceId, String databaseId) throws SQLException {
String connectionUrl =
String.format(
"jdbc:cloudspanner:/projects/%s/instances/%s/databases/%s",
projectId, instanceId, databaseId);
ImmutableList<Singer> singers = ImmutableList.of(
new Singer(10, "Marc", "Richards", BigDecimal.valueOf(10000)),
new Singer(11, "Amirah", "Finney", BigDecimal.valueOf(195944.10d)),
new Singer(12, "Reece", "Dunn", BigDecimal.valueOf(10449.90))
);
try (Connection connection = DriverManager.getConnection(connectionUrl)) {
connection.setAutoCommit(false);
// Use prepared statements for the lowest possible latency when executing the same SQL string
// multiple times.
try (PreparedStatement statement = connection.prepareStatement(
"INSERT INTO Singers (SingerId, FirstName, LastName, Revenues)\n"
+ "VALUES (?, ?, ?, ?)")) {
for (Singer singer : singers) {
statement.setLong(1, singer.singerId);
statement.setString(2, singer.firstName);
statement.setString(3, singer.lastName);
statement.setBigDecimal(4, singer.revenues);
// Add the current parameter values to the batch.
statement.addBatch();
}
// Execute the batched statements.
int[] updateCounts = statement.executeBatch();
connection.commit();
System.out.printf("Batch insert counts: %s%n", Arrays.toString(updateCounts));
}
}
}
}
SQL 쿼리 실행
다음 코드 예에서는 Singers 테이블의 모든 행을 가수의 성을 기준으로 정렬합니다.
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class SingleUseReadOnlyExample {
static void singleUseReadOnly() throws SQLException {
// TODO(developer): Replace these variables before running the sample.
String projectId = "my-project";
String instanceId = "my-instance";
String databaseId = "my-database";
singleUseReadOnly(projectId, instanceId, databaseId);
}
static void singleUseReadOnly(String projectId, String instanceId, String databaseId)
throws SQLException {
String connectionUrl =
String.format(
"jdbc:cloudspanner:/projects/%s/instances/%s/databases/%s",
projectId, instanceId, databaseId);
try (Connection connection = DriverManager.getConnection(connectionUrl);
Statement statement = connection.createStatement()) {
// When the connection is in autocommit mode, any query that is executed will automatically
// be executed using a single-use read-only transaction, even if the connection itself is in
// read/write mode.
try (ResultSet rs =
statement.executeQuery(
"SELECT SingerId, FirstName, LastName, Revenues FROM Singers ORDER BY LastName")) {
while (rs.next()) {
System.out.printf(
"%d %s %s %s%n",
rs.getLong(1), rs.getString(2), rs.getString(3), rs.getBigDecimal(4));
}
}
}
}
}
