## Why is this an issue?

Executing a batch of SQL queries instead of individual queries improves performance by reducing communication overhead with the database.

Batching SQL statements is beneficial in common situations where a SQL statement is executed within a loop. In such cases, adding the statement to a batch and subsequently executing it reduces the number of interactions with the database. This results in improved efficiency and faster execution times.

The rule raises an issue when it detects a `java.sql.Statement` being executed within a loop instruction, such as `for`, `while` or the `forEach` method of `java.lang.Iterable`, `java.util.Map` and `java.util.stream.Stream`.

## How to fix it

Group SQL statements by using the method `addBatch` to add them to a batch and then execute them using `executeBatch` to send them to the database in a single call.

### Code examples

#### Noncompliant code example

    public void execute(Connection connection) {
      try {
        Statement statement = connection.createStatement();

        for (int i = 0; i < 10; i++) {
          statement.execute("INSERT INTO myTable (column1, column2) VALUES (" + i + ", 'value" + i + "')"); // Noncompliant
        }

        statement.close();
        connection.close();
      } catch (SQLException e) {
        e.printStackTrace();
      }
    }

#### Compliant solution

    public void execute(Connection connection) {
      try {
        Statement statement = connection.createStatement();

        for (int i = 0; i < 10; i++) {
          statement.addBatch("INSERT INTO myTable (column1, column2) VALUES (" + i + ", 'value" + i + "')"); // Compliant
        }
        statement.executeBatch();

        statement.close();
        connection.close();
      } catch (SQLException e) {
        e.printStackTrace();
      }
    }

## Resources

### Documentation

- Oracle Java SE 21 API - java.sql.Statement
- Oracle Java SE 21 API - java.sql.PreparedStatement

### Articles & blog posts

- Baeldung - JDBC Batch Processing