ResultSet exception - before start of result set

Question

I'm having trouble getting data from a ResultSet object. Here is my code:

    String sql = "SELECT type FROM node WHERE nid = ?";     PreparedStatement prep = conn.prepareStatement(sql);     int meetNID = Integer.parseInt(node.get(BoutField.field_meet_nid));     prep.setInt(1, meetNID);      ResultSet result = prep.executeQuery();     result.beforeFirst();     String foundType = result.getString(1);      if (! foundType.equals("meet")) {         throw new IllegalArgumentException(String.format("Node %d must be of type 'meet', but was %s", meetNID, foundType));     } 

The error trace:

Exception in thread "main" java.sql.SQLException: Before start of result set     at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1072)     at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:986)     at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:981)     at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:926)     at com.mysql.jdbc.ResultSetImpl.checkRowPos(ResultSetImpl.java:841)     at com.mysql.jdbc.ResultSetImpl.getStringInternal(ResultSetImpl.java:5656)     at com.mysql.jdbc.ResultSetImpl.getString(ResultSetImpl.java:5576)     at nth.cumf3.nodeImport.Validator.validate(Validator.java:43)     at nth.cumf3.nodeImport.Main.main(Main.java:38) 

What am I doing wrong here?

Answer 1

Basically you are positioning the cursor before the first row and then requesting data. You need to move the cursor to the first row.

 result.next();  String foundType = result.getString(1); 

It is common to do this in an if statement or loop.

if(result.next()){    foundType = result.getString(1); } 

Answer 2

Every answer uses .next() or uses .beforeFirst() and then .next(). But why not this:

result.first(); 

So You just set the pointer to the first record and go from there. It's available since java 1.2 and I just wanted to mention this for anyone whose ResultSet exists of one specific record.