How to use an ArrayList as a Prepared Statement Parameter?

ArrayList is part of the Java Collection Framework and In this article, we will learn how to use an ArrayList as a prepared statement parameter.

Prepared Statement

It is a subinterface of the Statement interface. It is used to execute SQL parameterized queries and enhance performance and security. Here is an example of SQL parameterized queries.

String s="insert into emp values(?,?,?)";  

In the above example, we are passing the parameter '?' for the values. Their values are set when we call the setter method of the PreparedStatement.

Prerequisites:

• Basics of JDBC
• SQL
• Basics of ArrayList

JDBC Prepared Statements and ArrayList

Prepared Statements in JDBC are used for the compilation of SQL queries, enhancing performance by reducing overhead. Parameters that are used in Prepared Statements are represented by placeholders, which are denoted by '?' in the String of SQL query. When ArrayLists are used as parameters, dynamic values can be passed to the SQL query without the need for explicit parameters.

To implement this:

• Construct the String of SQL query with placeholders ('?') corresponding to the number of elements present in the ArrayList.
• Iterate over the ArrayList to set parameters in the Prepared Statement using appropriate setter methods.
• Execute the query and process the ResultSet to obtain the desired output.

Program for Arraylist as a Prepared Statement Parameter

Below is the solution for how to use an arraylist as a prepared statement parameter:

// Java Program to use ArrayList as
// Prepared Statement Parameter
package gfg;

import java.sql.*;
import java.util.ArrayList;

public class PreparedStatementExample {
    public static void main(String[] args) {
        // Connection parameters
        String url = "jdbc:oracle:thin:@localhost:1521:orcl";
        String username = "vinay";
        String password = "1234";

        try {
            // Load Oracle JDBC driver
            Class.forName("oracle.jdbc.driver.OracleDriver");

            // Create connection
            Connection connection = DriverManager.getConnection(url, username, password);

            ArrayList<Integer> empIds = new ArrayList<>();
            empIds.add(1);
            empIds.add(2);
            empIds.add(3);

            // Construct SQL query with placeholders
            StringBuilder sql = new StringBuilder("SELECT * FROM emp WHERE empno IN (");
            for (int i = 0; i < empIds.size(); i++) {
                sql.append(i == 0 ? "?" : ", ?");
            }
            sql.append(")");

            // Prepare the statement
            PreparedStatement statement = connection.prepareStatement(sql.toString());

            // Set parameters using ArrayList values
            for (int i = 0; i < empIds.size(); i++) {
                statement.setInt(i + 1, empIds.get(i));
            }

            // Execute query
            ResultSet resultSet = statement.executeQuery();

            // Process the result set
            while (resultSet.next()) {
                System.out.println("Employee ID: " + resultSet.getInt("empno") +
                        ", Name: " + resultSet.getString("empname") +
                        ", Salary: " + resultSet.getDouble("sal") +
                        ", Department Number: " + resultSet.getInt("deptno"));
            }

            // Close resources
            resultSet.close();
            statement.close();
            connection.close();

        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
        }
    }
}

Output:

Explanation of the above example:

First, We have to Connect JDBC with the five simple Steps:

• Register the Driver class: using forName() method
• Create connection: getConnection() method is used to create connection
• Create statement: createStatement() is used for statement(here, we use PreparedStatement)
• Execute queries: executeQuery() is used to execute the Query.
• Close Connection: close() is used to close the connection.

For more information refer to the table mentioned below:

Conclusion

Including ArrayLists as parameters in JDBC API Prepared Statements extends the database flexibility and versatility in Java applications. This is one of the way which allows for dynamic query execution, accommodating varying lengths of input data without compromising security or performance. Understanding and leveraging this capability empowers developers to build robust and scalable database-driven applications effectively.