? CallableStatement

? Quick Overview

CallableStatement is an interface in JDBC used to call stored procedures and functions defined in the database. It allows Java applications to execute complex SQL logic that runs directly on the database server.

? Key Concepts

Used for calling stored procedures
Supports IN, OUT, and INOUT parameters
Improves performance by executing logic at database level
Part of java.sql package

? Syntax / Theory

A CallableStatement is created using the prepareCall() method of the Connection interface.

? View Code Example

// Creating a CallableStatement to call a stored procedure
CallableStatement cs = con.prepareCall("{call procedure_name(?, ?)}");

? Interactive Visualizer

Simulate how IN parameters travel to the DB and OUT parameters travel back.

☕ Java App
(Source)

?️ Database
(Stored Proc)

Status: Ready to call procedure...

? Code Example

? View Code Example

// Calling a stored procedure with IN and OUT parameters
CallableStatement cs = con.prepareCall("{call getEmployeeName(?, ?)}");
cs.setInt(1, 101);
cs.registerOutParameter(2, java.sql.Types.VARCHAR);
cs.execute();
String name = cs.getString(2);

? Live Output / Explanation

?️ Output

The stored procedure is executed in the database. The OUT parameter returns the employee name, which is retrieved using getString() in Java.

? Tips & Best Practices

Always register OUT parameters before executing the statement
Use stored procedures for repeated and complex database logic
Close CallableStatement objects to avoid resource leaks

? Try It Yourself

Create a stored procedure that returns total salary of an employee
Call the procedure using CallableStatement
Experiment with INOUT parameters