Question

I understand the main difference between using Statement and PreparedStatement (PreparedStatements allow passing in parameters). But I read about a subtle difference between the two – namely that PreparedStatements can be quicker than generic Statements, because PreparedStatement SQL is precompiled.

What exactly does being precompiled mean, and why does it make a difference?

Answer 1

A prepared statement performs the following checks:

• Makes sure that the tables and columns exist
• Makes sure that the parameter types match their columns
• Parses the SQL to make sure that the syntax is correct
• Compiles and caches the compiled SQL so it can be re-executed without repeating these steps