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Table of Contents
Basic Use Cases
How to Create a Statement Object
Running Queries With Statement
Executing Updates and Commands
Limitations and Alternatives
Home Java javaTutorial What is a `Statement` object?

What is a `Statement` object?

Jul 01, 2025 am 12:37 AM
jdbc

A Statement object in Java is used to execute SQL queries and commands with a database via JDBC. 1. It allows execution of SELECT, INSERT, UPDATE, DELETE, and DDL statements. 2. It is created using the createStatement() method of a Connection object. 3. ResultSet handles query results by iterating through rows. 4. executeUpdate() modifies data and returns affected row count. 5. It poses SQL injection risks, making PreparedStatement a safer alternative for user input.

What is a `Statement` object?

A Statement object in programming, especially in the context of Java and databases, is used to send SQL statements to a database. It’s part of the JDBC (Java Database Connectivity) API and allows you to execute queries and update data.

Basic Use Cases

The main job of a Statement object is to carry your SQL command from your Java application to the database. You typically create one after connecting to the database using a Connection object.

Common things you can do with it:

  • Run SELECT queries to get data
  • Execute INSERT, UPDATE, or DELETE commands
  • Send DDL commands like CREATE TABLE

It's pretty straightforward for simple database interactions.

How to Create a Statement Object

You don’t use new Statement() directly. Instead, you call the createStatement() method on your Connection object.

Like this:

Connection connection = DriverManager.getConnection(url, username, password);
Statement statement = connection.createStatement();

Once created, you can use it to run SQL commands.

You usually follow this flow:

  1. Connect to the database
  2. Create the statement
  3. Use it to execute SQL
  4. Close it when done

Make sure to close it to avoid resource leaks — either manually or using try-with-resources.

Running Queries With Statement

To retrieve data from the database, you’ll use the executeQuery() method. This returns a ResultSet which holds the results of your query.

Example:

ResultSet resultSet = statement.executeQuery("SELECT * FROM users");
while (resultSet.next()) {
    System.out.println(resultSet.getString("username"));
}

This lets you loop through rows and extract column values.

A few things to remember:

  • Always check if the result set has rows before processing
  • Move the cursor with next()
  • Get data using column names or indexes

Be careful not to assume the order of columns unless you're certain.

Executing Updates and Commands

When you want to change data — insert new records, update existing ones, or delete them — you use the executeUpdate() method.

For example:

int rowsAffected = statement.executeUpdate("UPDATE users SET email = 'new@example.com' WHERE id = 1");
System.out.println(rowsAffected   " row(s) updated.");

This gives you the number of rows impacted by the operation.

You can also use it for table creation or deletion:

statement.executeUpdate("CREATE TABLE test (id INT PRIMARY KEY)");

But be cautious with schema changes in production code.

Limitations and Alternatives

While Statement objects are useful, they have some downsides — especially around security and performance.

Biggest issue? SQL injection risk when concatenating user input into queries.

Better options exist:

  • PreparedStatement – for parameterized queries
  • CallableStatement – for stored procedures

These give safer and more efficient ways to interact with databases, especially in applications where user input is involved.

If you’re writing anything beyond a quick test, consider moving to prepared statements sooner rather than later.


That’s basically what a Statement object is and how it works. Not too complex, but important to understand for basic database operations in Java.

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