Derby Database Tutorial for Beginners201

Introduction

Apache Derby is an open-source, Java-based relational database management system (RDBMS) that is lightweight, embeddable, and easy to use. It is commonly used for embedded applications, such as mobile apps and web services, where a small footprint and low maintenance overhead are essential.

Installing Derby

Derby can be installed by downloading the binary distribution from the Apache website. It is available for Windows, macOS, and Linux platforms. Once downloaded, you can extract the contents of the archive to a convenient location.

Creating a Database

To create a Derby database, you can use the following Java code:
import .*;
public class CreateDatabase {
public static void main(String[] args) {
try {
// Create a connection to the JDBC URL for the embedded Derby database
Connection conn = ("jdbc:derby:myDatabase;create=true");
// Check if the database successfully created
DatabaseMetaData meta = ();
if (().equals("Apache Derby")) {
("Database created successfully!");
} else {
("Error creating database");
}
// Close the connection
();
} catch (SQLException e) {
();
}
}
}

Connecting to a Database

Once you have created a database, you can connect to it using the following Java code:
import .*;
public class ConnectDatabase {
public static void main(String[] args) {
try {
// Create a connection to the JDBC URL for the embedded Derby database
Connection conn = ("jdbc:derby:myDatabase");
// Check if the connection was successful
if (conn != null) {
("Connected to database successfully!");
} else {
("Error connecting to database");
}
// Close the connection
();
} catch (SQLException e) {
();
}
}
}

Creating a Table

A database table is a collection of related data. To create a table in Derby, you can use the following Java code:
import .*;
public class CreateTable {
public static void main(String[] args) {
try {
// Create a connection to the Derby database
Connection conn = ("jdbc:derby:myDatabase");
// Create a statement object
Statement stmt = ();
// Create a SQL statement to create the table
String sql = "CREATE TABLE users (id INT NOT NULL, name VARCHAR(255), PRIMARY KEY (id))";
// Execute the SQL statement
(sql);
// Check if the table was successfully created
DatabaseMetaData meta = ();
ResultSet rs = (null, null, "users", null);
if (()) {
("Table created successfully!");
} else {
("Error creating table");
}
// Close the statement and connection
();
();
} catch (SQLException e) {
();
}
}
}

Inserting Data

To insert data into a table, you can use the following Java code:
import .*;
public class InsertData {
public static void main(String[] args) {
try {
// Create a connection to the Derby database
Connection conn = ("jdbc:derby:myDatabase");
// Create a statement object
Statement stmt = ();
// Create a SQL statement to insert data
String sql = "INSERT INTO users (id, name) VALUES (1, 'John Doe')";
// Execute the SQL statement
(sql);
// Check if the data was successfully inserted
ResultSet rs = ("SELECT * FROM users");
if (()) {
("Data inserted successfully!");
} else {
("Error inserting data");
}
// Close the statement and connection
();
();
} catch (SQLException e) {
();
}
}
}

Retrieving Data

To retrieve data from a table, you can use the following Java code:
import .*;
public class RetrieveData {
public static void main(String[] args) {
try {
// Create a connection to the Derby database
Connection conn = ("jdbc:derby:myDatabase");
// Create a statement object
Statement stmt = ();
// Create a SQL statement to retrieve data
String sql = "SELECT * FROM users";
// Execute the SQL statement
ResultSet rs = (sql);
// Iterate over the result set and print the data
while (()) {
("ID: " + ("id") + ", Name: " + ("name"));
}
// Close the statement and connection
();
();
} catch (SQLException e) {
();
}
}
}

Updating Data

To update data in a table, you can use the following Java code:
import .*;
public class UpdateData {
public static void main(String[] args) {
try {
// Create a connection to the Derby database
Connection conn = ("jdbc:derby:myDatabase");
// Create a statement object
Statement stmt = ();
// Create a SQL statement to update data
String sql = "UPDATE users SET name = 'Jane Doe' WHERE id = 1";
// Execute the SQL statement
(sql);
// Check if the data was successfully updated
ResultSet rs = ("SELECT * FROM users WHERE id = 1");
if (()) {
("Data updated successfully!");
} else {
("Error updating data");
}
// Close the statement and connection
();
();
} catch (SQLException e) {
();
}
}
}

Deleting Data

To delete data from a table, you can use the following Java code:
import .*;
public class DeleteData {
public static void main(String[] args) {
try {
// Create a connection to the Derby database
Connection conn = ("jdbc:derby:myDatabase");
// Create a statement object
Statement stmt = ();
// Create a SQL statement to delete data
String sql = "DELETE FROM users WHERE id = 1";
// Execute the SQL statement
(sql);
// Check if the data was successfully deleted
ResultSet rs = ("SELECT * FROM users WHERE id = 1");
if (!()) {
("Data deleted successfully!");
} else {
("Error deleting data");
}
// Close the statement and connection
();
();
} catch (SQLException e) {
();
}
}
}

Conclusion

This tutorial provided a comprehensive overview of using Derby for basic database operations. By following the steps outlined in this guide, you can easily create, connect to, and manipulate data in a Derby database.

2024-11-28

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