When using 8.4 JDBC drivers, calling prepareStatement(String sql, int
autoGeneratedKeys) with Statement.RETURN_GENERATED_KEYS seems to add
"RETURNING *" to the end of the SQL even with select statements.
According to Javadoc for prepareStatement(String sql, int
autoGeneratedKeys) in java.sql.Connection:
"The given constant tells the driver whether it should make
auto-generated keys available for retrieval. This parameter is ignored
if the SQL statement is not an INSERT statement, or an SQL statement
able to return auto-generated keys (the list of such statements is
vendor-specific). "
Here's a simple test class to demonstrate this problem:
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.sql.Statement;
public class PostgrePrepareStatementTest {
public static void main(String[] args) throws
InstantiationException, IllegalAccessException, ClassNotFoundException,
SQLException {
Class.forName("org.postgresql.Driver").newInstance();
String url = "jdbc:postgresql://localhost:5432/testdb";
Connection conn = DriverManager.getConnection(url, "user",
"password");
PreparedStatement pStmt = conn.prepareStatement("select * from
test_table", Statement.RETURN_GENERATED_KEYS);
System.out.println(pStmt.toString());
pStmt.execute();
}
}
When run this prints "select * from test_table RETURNING *" - which is
invalid - and an exception is thrown:
Exception in thread "main" org.postgresql.util.PSQLException: ERROR:
syntax error at or near "RETURNING"
Position: 26
at
org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2062)
at
org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1795)
at
org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:257)
at
org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:479)
at
org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:367)
at
org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:360)
at
com.smilehouse.PostgrePrepareStatementTest.main(PostgrePrepareStatementTest.java:17)
I have tested this with driver version 8.4-701 (both JDBC3 and JDBC4).
The PostgreSQL version was 8.4.
-Heikki Hiltunen