JDBC | Kode Java - Learn Java by Examples

How do I check if the OUT parameter value is null?

By Wayan in JDBC Last modified: August 3, 2023 0 Comment

This example show you how to use the CallableStatement.wasNull() method call to see if the last OUT parameter has a value of SQL NULL.

package org.kodejava.jdbc;

import java.math.BigDecimal;
import java.sql.Connection;
import java.sql.CallableStatement;
import java.sql.DriverManager;
import java.sql.Types;
import java.sql.SQLException;

public class WasNullExample {
    private static final String URL = "jdbc:mysql://localhost/kodejava";
    private static final String USERNAME = "kodejava";
    private static final String PASSWORD = "s3cr*t";

    public static void main(String[] args) {
        try (Connection connection =
                     DriverManager.getConnection(URL, USERNAME, PASSWORD)) {

            // Prepares a call to the sored procedure
            String query = "call Get_Product_By_Price2(?, ?)";
            CallableStatement cb = connection.prepareCall(query);

            // Sets the input parameter
            cb.setBigDecimal(1, new BigDecimal("50"));

            // Registers the OUT parameter
            cb.registerOutParameter(2, Types.VARCHAR);

            // Executes the query
            cb.executeQuery();

            // Gets the OUT parameter value
            cb.getString(2);

            // Checks if the last OUT parameter has the value of SQL NULL.
            // This method should be called only after calling a getter
            // method; otherwise, there is no value to use in determining
            // whether it is null or not.
            if (cb.wasNull()) {
                System.out.println("Product has an SQL NULL value");
            } else {
                System.out.println("Product: " + cb.getString(2));
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

Here is the stored procedure script we called in the example above.

DELIMITER ;;
DROP PROCEDURE IF EXISTS Get_Product_By_Price2;;
CREATE PROCEDURE Get_Product_By_Price2(
    IN product_price DECIMAL(10, 2),
    OUT product_name VARCHAR(100))
BEGIN
    SELECT name
    INTO product_name
    FROM product
    WHERE price = product_price;
END;;
DELIMITER ;

Maven Dependencies

<dependency>
    <groupId>com.mysql</groupId>
    <artifactId>mysql-connector-j</artifactId>
    <version>8.1.0</version>
</dependency>

How do I call a stored procedure that return a result set?

By Wayan in JDBC Last modified: July 23, 2023 0 Comment

This example show you how to call a stored procedure that return a result set of the query execution result.

package org.kodejava.jdbc;

import java.math.BigDecimal;
import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;

public class CallableStatementExample {
    private static final String URL = "jdbc:mysql://localhost/kodejava";
    private static final String USERNAME = "kodejava";
    private static final String PASSWORD = "s3cr*t";

    public static void main(String[] args) {
        try (Connection connection =
                     DriverManager.getConnection(URL, USERNAME, PASSWORD)) {

            // Prepares a call to the stored procedure. This stored procedure takes
            // one IN parameter
            String query = "call Get_Product_By_Price(?)";
            CallableStatement cb = connection.prepareCall(query);

            // Sets the input parameter
            cb.setBigDecimal(1, new BigDecimal("50.39"));

            // Execute the query
            ResultSet rs = cb.executeQuery();

            while (rs.next()) {
                System.out.println("Product: " + rs.getString(1));
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

Here is the stored procedure script we use in the example above.

DELIMITER ;;
DROP PROCEDURE IF EXISTS Get_Product_By_Price;;
CREATE PROCEDURE Get_Product_By_Price(IN product_price DECIMAL(10, 2))
BEGIN
    SELECT name FROM product WHERE price = product_price;
END;;
DELIMITER ;

Maven dependencies

<dependency>
    <groupId>com.mysql</groupId>
    <artifactId>mysql-connector-j</artifactId>
    <version>8.1.0</version>
</dependency>

How do I register out parameter in CallableStatement?

By Wayan in JDBC Last modified: July 31, 2023 0 Comment

This example show you how to register out parameter for executing a stored procedure using the CallableStatement.registerOutParameter() method call. We must register the out parameters before the query execution. The registerOutParameter() method takes two parameters, the index of the parameter and the sql data type of the out parameter.

package org.kodejava.jdbc;

import java.sql.*;

public class RegisterOutParameter {
    private static final String URL = "jdbc:mysql://localhost/kodejava";
    private static final String USERNAME = "kodejava";
    private static final String PASSWORD = "s3cr*t";

    public static void main(String[] args) {
        try (Connection connection =
                     DriverManager.getConnection(URL, USERNAME, PASSWORD)) {

            // Creates a CallableStatement for executing the stored
            // procedure
            String query = "call Get_Product_Detail_By_Name(?, ?, ?)";
            CallableStatement cb = connection.prepareCall(query);

            // Sets the input parameter
            cb.setString(1, "Data Structures, Algorithms");

            // Registers the out parameters
            cb.registerOutParameter(2, Types.VARCHAR);
            cb.registerOutParameter(3, Types.DECIMAL);

            // Executes the query
            cb.executeQuery();

            // Gets the query result output
            System.out.println("Name  : " + cb.getString(1));
            System.out.println("Code  : " + cb.getString(2));
            System.out.println("Price : " + cb.getBigDecimal(3));
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

Here is the MySQL stored procedure that we call in the code above.

DELIMITER ;;
DROP PROCEDURE IF EXISTS `Get_Product_Detail_By_Name`;;
CREATE PROCEDURE `Get_Product_Detail_By_Name`(
    INOUT product_name VARCHAR(100),
    OUT product_code VARCHAR(20),
    OUT product_price DECIMAL(10, 2))
BEGIN
    SELECT code INTO product_code FROM product WHERE name = product_name;

    SELECT price INTO product_price FROM product WHERE name = product_name;
END;;
DELIMITER ;

Maven Dependencies

<dependency>
    <groupId>com.mysql</groupId>
    <artifactId>mysql-connector-j</artifactId>
    <version>8.1.0</version>
</dependency>

How do I set the query timeout limit?

By Wayan in JDBC Last modified: July 31, 2023 1 Comment

The Statement.setQueryTimeout() method set the limit in seconds for query execution time. The execution has no timeout limit when the value is set to zero.

package org.kodejava.jdbc;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
import java.sql.SQLException;
import java.sql.DriverManager;

public class QueryTimeout {
    private static final String URL = "jdbc:mysql://localhost/kodejava";
    private static final String USERNAME = "kodejava";
    private static final String PASSWORD = "s3cr*t";

    public static void main(String[] args) {
        try (Connection connection =
                     DriverManager.getConnection(URL, USERNAME, PASSWORD)) {
            Statement stmt = connection.createStatement();

            // Sets the number of seconds the driver will wait for
            // a statement object to execute to the given number of
            // seconds. If the limit is exceeded, an SQLException
            // is thrown.
            stmt.setQueryTimeout(60);

            // Execute sql query
            ResultSet rs = stmt.executeQuery("select * from product");

            while (rs.next()) {
                System.out.println("code: " + rs.getString("code") + 
                                   ", product: " + rs.getString("name") + 
                                   ", price: " + rs.getDouble("price"));
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

Maven Dependencies

<dependency>
    <groupId>com.mysql</groupId>
    <artifactId>mysql-connector-j</artifactId>
    <version>8.1.0</version>
</dependency>

How do I limit MySQL query result?

By Wayan in JDBC Last modified: July 31, 2023 0 Comment

package org.kodejava.jdbc;

import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class SqlLimitExample {
    private static final String URL = "jdbc:mysql://localhost/kodejava";
    private static final String USERNAME = "kodejava";
    private static final String PASSWORD = "s3cr*t";

    public static void main(String[] args) {
        try (Connection connection =
                     DriverManager.getConnection(URL, USERNAME, PASSWORD)) {

            // Create PreparedStatement to get all data from a database.
            String query = "select count(*) from product";
            PreparedStatement ps = connection.prepareStatement(query);
            ResultSet result = ps.executeQuery();

            int total = 0;
            while (result.next()) {
                total = result.getInt(1);
            }

            System.out.println("Total number of data in database: " +
                               total + "\n");

            // Create PreparedStatement to the first 5 records only.
            query = "select * from product limit 5";
            ps = connection.prepareStatement(query);
            result = ps.executeQuery();

            System.out.println("Result fetched with specified limit 5");
            System.out.println("====================================");
            while (result.next()) {
                System.out.println("id:" + result.getInt("id") +
                                   ", code:" + result.getString("code") +
                                   ", name:" + result.getString("name") +
                                   ", price:" + result.getString("price"));
            }

            // Create PreparedStatement to get data from the 4th
            // record (remember the first record is 0) and limited
            // to 3 records only.
            query = "select * from product limit 3, 3";
            ps = connection.prepareStatement(query);
            result = ps.executeQuery();

            System.out.println("\nResult fetched with specified limit 3, 3");
            System.out.println("====================================");
            while (result.next()) {
                System.out.println("id:" + result.getInt("id") +
                                   ", code:" + result.getString("code") +
                                   ", name:" + result.getString("name") +
                                   ", price:" + result.getString("price"));
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

An example result of our program is:

Total number of data in database: 9

Result fetched with specified limit 5
====================================
id:1, code:P0000001, name:UML Distilled 3rd Edition, price:25.00
id:3, code:P0000003, name:PHP Programming, price:20.00
id:4, code:P0000004, name:Longman Active Study Dictionary, price:40.00
id:5, code:P0000005, name:Ruby on Rails, price:24.00
id:6, code:P0000006, name:Championship Manager, price:0.00

Result fetched with specified limit 3, 3
====================================
id:5, code:P0000005, name:Ruby on Rails, price:24.00
id:6, code:P0000006, name:Championship Manager, price:0.00
id:7, code:P0000007, name:Transport Tycoon Deluxe, price:0.00

Maven Dependencies

<dependency>
    <groupId>com.mysql</groupId>
    <artifactId>mysql-connector-j</artifactId>
    <version>8.1.0</version>
</dependency>