org.apache.beam.sdk.io.jdbc

Class JdbcIO

java.lang.Object

org.apache.beam.sdk.io.jdbc.JdbcIO

@Experimental(value=SOURCE_SINK)
public class JdbcIO
extends java.lang.Object

IO to read and write data on JDBC.

Reading from JDBC datasource

JdbcIO source returns a bounded collection of T as a PCollection<T>. T is the type returned by the provided JdbcIO.RowMapper.

To configure the JDBC source, you have to provide a JdbcIO.DataSourceConfiguration using
1. JdbcIO.DataSourceConfiguration.create(DataSource)(which must be Serializable);
2. or JdbcIO.DataSourceConfiguration.create(String, String)(driver class name and url). Optionally, JdbcIO.DataSourceConfiguration.withUsername(String) and JdbcIO.DataSourceConfiguration.withPassword(String) allows you to define username and password.

For example:

 pipeline.apply(JdbcIO.<KV<Integer, String>>read()
   .withDataSourceConfiguration(JdbcIO.DataSourceConfiguration.create(
          "com.mysql.jdbc.Driver", "jdbc:mysql://hostname:3306/mydb")
        .withUsername("username")
        .withPassword("password"))
   .withQuery("select id,name from Person")
   .withCoder(KvCoder.of(BigEndianIntegerCoder.of(), StringUtf8Coder.of()))
   .withRowMapper(new JdbcIO.RowMapper<KV<Integer, String>>() {
     public KV<Integer, String> mapRow(ResultSet resultSet) throws Exception {
       return KV.of(resultSet.getInt(1), resultSet.getString(2));
     }
   })
 );
 

Query parameters can be configured using a user-provided JdbcIO.StatementPreparator. For example:

 pipeline.apply(JdbcIO.<KV<Integer, String>>read()
   .withDataSourceConfiguration(JdbcIO.DataSourceConfiguration.create(
       "com.mysql.jdbc.Driver", "jdbc:mysql://hostname:3306/mydb",
       "username", "password"))
   .withQuery("select id,name from Person where name = ?")
   .withCoder(KvCoder.of(BigEndianIntegerCoder.of(), StringUtf8Coder.of()))
   .withStatementPreparator(new JdbcIO.StatementPreparator() {
     public void setParameters(PreparedStatement preparedStatement) throws Exception {
       preparedStatement.setString(1, "Darwin");
     }
   })
   .withRowMapper(new JdbcIO.RowMapper<KV<Integer, String>>() {
     public KV<Integer, String> mapRow(ResultSet resultSet) throws Exception {
       return KV.of(resultSet.getInt(1), resultSet.getString(2));
     }
   })
 );
 

Writing to JDBC datasource

JDBC sink supports writing records into a database. It writes a PCollection to the database by converting each T into a PreparedStatement via a user-provided JdbcIO.PreparedStatementSetter.

Like the source, to configure the sink, you have to provide a JdbcIO.DataSourceConfiguration.

 pipeline
   .apply(...)
   .apply(JdbcIO.<KV<Integer, String>>write()
      .withDataSourceConfiguration(JdbcIO.DataSourceConfiguration.create(
            "com.mysql.jdbc.Driver", "jdbc:mysql://hostname:3306/mydb")
          .withUsername("username")
          .withPassword("password"))
      .withStatement("insert into Person values(?, ?)")
      .withPreparedStatementSetter(new JdbcIO.PreparedStatementSetter<KV<Integer, String>>() {
        public void setParameters(KV<Integer, String> element, PreparedStatement query)
          throws SQLException {
          query.setInt(1, kv.getKey());
          query.setString(2, kv.getValue());
        }
      })
    );
 

NB: in case of transient failures, Beam runners may execute parts of JdbcIO.Write multiple times for fault tolerance. Because of that, you should avoid using INSERT statements, since that risks duplicating records in the database, or failing due to primary key conflicts. Consider using MERGE ("upsert") statements supported by your database instead.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	JdbcIO.DataSourceConfiguration A POJO describing a DataSource, either providing directly a DataSource or all properties allowing to create a DataSource.
static interface	JdbcIO.PreparedStatementSetter<T> An interface used by the JdbcIO Write to set the parameters of the PreparedStatement used to setParameters into the database.
static class	JdbcIO.Read<T> Implementation of read().
static class	JdbcIO.ReadAll<ParameterT,OutputT> Implementation of read().
static interface	JdbcIO.RowMapper<T> An interface used by JdbcIO.Read for converting each row of the ResultSet into an element of the resulting PCollection.
static interface	JdbcIO.StatementPreparator An interface used by the JdbcIO Write to set the parameters of the PreparedStatement used to setParameters into the database.
static class	JdbcIO.Write<T> A PTransform to write to a JDBC datasource.

Method Summary

Modifier and Type	Method and Description
static <T> JdbcIO.Read<T>	read() Read data from a JDBC datasource.
static <ParameterT,OutputT> JdbcIO.ReadAll<ParameterT,OutputT>	readAll() Like read(), but executes multiple instances of the query substituting each element of a PCollection as query parameters.
static <T> JdbcIO.Write<T>	write() Write data to a JDBC datasource.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

read

public static <T> JdbcIO.Read<T> read()

Read data from a JDBC datasource.

Type Parameters:

T - Type of the data to be read.

readAll

public static <ParameterT,OutputT> JdbcIO.ReadAll<ParameterT,OutputT> readAll()

Like read(), but executes multiple instances of the query substituting each element of a PCollection as query parameters.

Type Parameters:

ParameterT - Type of the data representing query parameters.

OutputT - Type of the data to be read.

write

public static <T> JdbcIO.Write<T> write()

Write data to a JDBC datasource.

Type Parameters:

T - Type of the data to be written.