Question

What is the best place to put PreparedStatement initialization, when i want to use it for all instances of given class?

My solution is so far to create static methods for opening and closing, but i don’t find it quite the right choice:

class Person {
    protected static PreparedStatement stmt1;
    protected static PreparedStatement stmt2;

    protected static void initStatements(Connection conn) {
        stmt1 = conn.PrepareStatement("select job_id from persons where person_id=:person_id");
        stmt2 = conn.PrepareStatement("update persons set job_id=:job_id where person_id=:person_id");
    }

    protected static void closeStatements() {
        stmt1.close();
        stmt2.close();
    }
    public void increaseSalary() {
        stmt1.execute(); // just a example 
        stmt2.execute();
    }
}

void main {
    // create prepared statements
    Person.initStatements(conn);

    // for each person, increase do some action which require sql connection
    for (Person p : getAllPersons()) {
        p.increaseSalary();
    }

    // close statements
    Person.closeStatements();
}

Isn’t there any other way how to use PreparedStatements inside multiple instances of class?

Answer 1

Will person be your domain logic class? Then I recommend not to put the data access methods and PreparedStatements in there but in a separate data access object.

Will the DAO methods be called asynchronously for example in a web application? Then I recommend to not reuse either PreparedStatements or Connections between those calls at all. For Connections I’d use a Connection pool.
More on reusing PreparedStatements:
Reusing a PreparedStatement multiple times