Code360 powered by Coding Ninjas X Naukri.com. Code360 powered by Coding Ninjas X Naukri.com
Table of contents
1.
Introduction
2.
What is a Prepared Statement in Java?
3.
Why do we Use Prepared Statements in Java?
3.1.
Advantages of Using Prepared Statement:
4.
Methods of Prepared Statement Java
5.
Steps to Use Prepared Statement
5.1.
Establish a Connection: 
5.2.
Create a Prepared Statement: 
5.3.
Set Parameters: 
5.4.
Execute the Statement: 
5.5.
Close the Statement and Connection: 
6.
Examples of Prepared Statements in Java
6.1.
Java
7.
Advantages of Prepared Statement in Java
8.
Frequently Asked Questions
8.1.
What is PreparedStatement in Java?
8.2.
What is the use of PreparedStatement?
8.3.
Is PreparedStatement a class or interface?
8.4.
Why do we need prepared statements?
9.
Conclusion
Last Updated: Mar 27, 2024
Easy

Prepared Statement Java

Author Ravi Khorwal
0 upvote
Crack Google SDE interview : Essential projects
Speaker
Saurav Prateek
SDE-2 @
20 Jun, 2024 @ 01:30 PM

Introduction

PreparedStatement in Java is a pre-compiled SQL statement with added features, serving as a refined version of the Statement interface for enhanced functionality in database operations.

Prepared Statement in Java

This article delves into the concept of prepared statements in Java, their advantages, and how to effectively utilize them with practical examples.

What is a Prepared Statement in Java?

A prepared statement is an object used in Java database connectivity (JDBC) that represents a precompiled SQL statement. This means that the SQL statement is parsed and compiled by the database server beforehand, which can then be executed multiple times with different parameters.

Get the tech career you deserve, faster!
Connect with our expert counsellors to understand how to hack your way to success
User rating 4.7/5
1:1 doubt support
95% placement record
Akash Pal
Senior Software Engineer
326% Hike After Job Bootcamp
Himanshu Gusain
Programmer Analyst
32 LPA After Job Bootcamp
After Job
Bootcamp

Why do we Use Prepared Statements in Java?

Prepared statements are used primarily to prevent SQL injection attacks, which can occur when executing raw SQL queries with user input. They also improve performance, especially for repetitive execution of similar SQL statements.

Advantages of Using Prepared Statement:

  • Enhanced Security: By precompiling the SQL statement, prepared statements separate the query structure from data values, mitigating the risk of SQL injection.
     
  • Improved Performance: Since the SQL statement is compiled only once, it reduces the overhead on the database server, leading to better performance.
     
  • Scalability: Prepared statements make it easier to work with dynamic queries, as they can be executed multiple times with different parameters.

Methods of Prepared Statement Java

setInt(int, int):


This method binds an integer value to a parameter index in the SQL statement.

PreparedStatement pstmt = con.prepareStatement("UPDATE users SET age = ? WHERE id = ?");
pstmt.setInt(1, 25); // Sets age to 25
pstmt.setInt(2, 1); // Sets id to 1
setString(int, string):


It assigns a string value to a specified parameter index.

pstmt.setString(1, "John Doe"); // Sets the name to "John Doe"
setFloat(int, float) and setDouble(int, double):


These methods are used for setting float and double values at specified parameter indexes.

pstmt.setFloat(1, 10.5f); // Sets a float value
pstmt.setDouble(2, 20.99); // Sets a double value


executeUpdate():

Executes the SQL statement for DML operations like insert, update, or delete, returning an integer representing the number of affected rows.

int rowsAffected = pstmt.executeUpdate();


executeQuery():

Executes the SQL statement and returns a ResultSet object for SELECT queries.

ResultSet rs = pstmt.executeQuery();

Steps to Use Prepared Statement

Establish a Connection: 

Create a connection to the database.

Connection conn = DriverManager.getConnection("jdbc:mysql://hostname:port/dbname", "username", "password");

Create a Prepared Statement: 

Use the connection to create a prepared statement object.

PreparedStatement pstmt = conn.prepareStatement("SELECT * FROM table WHERE column = ?");

Set Parameters: 

Bind values to the statement's parameters.

pstmt.setString(1, "value");

Execute the Statement: 

Execute the statement and retrieve results if applicable.

ResultSet rs = pstmt.executeQuery();

Close the Statement and Connection: 

Properly close resources to prevent leaks.

pstmt.close();
conn.close();

Examples of Prepared Statements in Java

Let's look at a complete example of using a prepared statement to insert data into a database

  • Java

Java

import java.sql.*;

public class PreparedStatementExample {

   public static void main(String[] args) {

       String url = "jdbc:mysql://localhost:3306/mydatabase";

       String user = "username";

       String password = "password";

       String sql = "INSERT INTO students (name, age, grade) VALUES (?, ?, ?)";


       try (Connection con = DriverManager.getConnection(url, user, password);

            PreparedStatement pstmt = con.prepareStatement(sql)) {


           // Set parameters for the prepared statement

           pstmt.setString(1, "Alice");

           pstmt.setInt(2, 20);

           pstmt.setDouble(3, 9.5);


           // Execute the insert operation

           int rowsInserted = pstmt.executeUpdate();

           System.out.println(rowsInserted + " rows inserted.");




       } catch (SQLException e) {

           e.printStackTrace();

       }

   }

}

Output

Output

In this example, we insert a new student record into the students table. We establish a connection, create a prepared statement with the SQL command, set the parameters, execute the update, and finally handle any exceptions that may occur.

Advantages of Prepared Statement in Java

Prepared statements offer numerous benefits:

  • Enhanced Performance: Prepared Statements are precompiled by the database, allowing faster execution, especially in repetitive queries.
  • Improved Security: They prevent SQL Injection attacks by handling input sanitization and enhancing security.
  • Reduced Code Complexity: Prepared Statements simplify query construction, particularly with dynamic parameters.
  • Better Scalability: They are efficient for batch processing and handling large-scale data operations.
  • Consistency and Clarity: They provide a clear and consistent approach to setting parameters in SQL queries.
  • Database Independence: Prepared Statements abstract some database-specific details, promoting more portable code.
  • Resource Optimization: They can reduce the database's workload by reusing compiled SQL queries.

Frequently Asked Questions

What is PreparedStatement in Java?

A PreparedStatement in Java is a subclass of Statement used in JDBC to execute parameterized SQL queries efficiently and securely, offering advantages like precompilation and protection against SQL injection attacks

What is the use of PreparedStatement?

The PreparedStatement in Java executes SQL queries with or without parameters. It enhances performance through query precompilation, ensures better security against SQL injection, and allows for easier parameter setting in SQL commands. It's beneficial for executing repetitive SQL operations efficiently in Java-based applications.

Is PreparedStatement a class or interface?

PreparedStatement in Java is an interface in the java.sql package. It extends the Statement interface and executes precompiled SQL statements with or without input parameters, offering enhanced performance and security in database operations.

Why do we need prepared statements?

Prepared statements are needed for efficient database interactions in Java. They improve performance by precompiling SQL queries, enhance security by preventing SQL injection attacks, and allow for dynamic query execution with variable inputs, ensuring safer and more optimized database operations.

Conclusion

Prepared statements are a robust feature of JDBC that provide security against SQL injection and enhance the performance of database operations. By understanding and implementing prepared statements as shown in the examples, developers can write more secure and efficient database-driven applications. Always ensure to close your resources and handle exceptions to maintain the integrity of your application and database.

You can refer to our guided paths on the Coding Ninjas. You can check our course to learn more about DSADBMSCompetitive ProgrammingPythonJavaJavaScript, etc. 

Also, check out some of the Guided Paths on topics such as Data Structure and AlgorithmsCompetitive ProgrammingOperating SystemsComputer Networks, DBMSSystem Design, etc., as well as some Contests, Test Series, and Interview Experiences curated by top Industry Experts.

Previous article
Lambda Expressions in Java
Next article
Managing Memory in Java
Live masterclass