如何从java中的executeUpdate或更新获取值？

Question

Im trying to get some returning data from an postgresql update. The "update" works well in the DB script, but in java I'm having some issues: the code stucks while executing the query.

I'm trying with "PreparedStatament ps", "ResultSet rs=ps.executeQuery" and "if(rs.next)" to get the data from the "returning" in the query, but it appears that the code didnt get in there, because it stuck exactly in the "ps.executeQuery".

Here's more or less what I'm trying to do:

String cVal="";
ps=myConn.prepareStatement("UPDATE someTable SET aValue=? WHERE bValue=? 
returning Cvalue");
ps.setInt(1,"aNewValue");
ps.setInt(2,"aID");
rs=ps.executeQuery();
if (rs.next()){
  cVal=rs.GetString("Cvalue");
  return true;
}else{
  return false;
}

I'm trying to set the values of "RETURNING" to some variables. There are 4 results that I want to set.

Answer 1

Since you are trying to update, in case of PreparedStatement, you have to use executeUpdate() method.

To know more details about methods in Statement and PreparedStatment, check below the

https://docs.oracle.com/javase/8/docs/api/java/sql/PreparedStatement.html#executeUpdate--

You can refer below an example. https://www.mkyong.com/jdbc/jdbc-preparestatement-example-update-a-record/

Answer 2

First execute the update statement with ps.executeUpdate () , which returns the integer 0 or 1 . The value indicates whether the update statement has executed or not. After that, execute the select query to get the updated data.