Prepared Statements along with Connection Pooling

Question

I have a question regarding general use of Prepared Statement along with connection pooling.

Prepared Statements are generally tied to one connection only.In our app

Answer 1

The value of PreparedStatement lies in the ability of the database itself to create an execution plan for the statement that can be reused for arbitrary parameters and thus is generic in nature (of course that requires that you use parameters in your statetment, e.g.

PreparedStatement pstmt = con.prepareStatement("UPDATE EMPLOYEES
                               SET SALARY = ? WHERE ID = ?");
pstmt.setBigDecimal(1, 153833.00);
pstmt.setInt(2, 110592);

If on the other hand you would use string concatenation to paste the parameter values into the SQL code, the database would not be able to build a generic execution plan. Thus it would make no difference if you use a PreparedStatement or Statement, e.g.

PreparedStatement pstmt = con.prepareStatement("UPDATE EMPLOYEES
                               SET SALARY = 1200 WHERE ID = 3");

would not be able to use the advantage of PreparedStatements.

Your question implies, that you want to reuse the PreparedStatement object, which is not necessary. Of course if you can use a PreparedStatement object to update multiple values etc. it is a more efficient use of ressources. Nevertheless the lifespan (or at least usefull lifespan) of the PreparedStatement is tied to the Connection, thus if you call conn.close() the PreparedStatement is rendered useless. Nevertheless most good drivers in a pooling situation reuse the same PreparedStatement objects again. In short, don't cache the PreparedStatement independent of the connection.