Getting auto-generated key from row insertion in spring 3 / PostgreSQL 8.4.9

Question

I would like to retrieve the auto-generated id from a row insertion, but I get a NullPointerException

Here is the code :

long result = 0         


        

Answer 1

I had the same problem and it turned out that my table ID was not auto incrementing.

Answer 2

Take a look at this post, especially the accepted answer of using the INSERT...RETURNING syntax:

How to get a value from the last inserted row?

This the best way to get this value in PostgreSQL as you only make one network round trip and it's done as a single atomic operation on the server.

Answer 3

KeyHolder holder = new GeneratedKeyHolder();

getJdbcTemplate().update(new PreparedStatementCreator() {           

                @Override
                public PreparedStatement createPreparedStatement(Connection connection)
                        throws SQLException {
                    PreparedStatement ps = connection.prepareStatement(sql.toString(),
                        Statement.RETURN_GENERATED_KEYS); 
                    ps.setString(1, person.getUsername());
                    ps.setString(2, person.getPassword());
                    ps.setString(3, person.getEmail());
                    ps.setLong(4, person.getRole().getId());
                    return ps;
                }
            }, holder);

Long newPersonId = holder.getKey().longValue();

Note that in newer versions of Postgres you need to use

connection.prepareStatement(sql.toString(), 
    new String[] { "idcompte" /* name of your id column */ })

instead of

connection.prepareStatement(sql.toString(), 
    Statement.RETURN_GENERATED_KEYS);