Docker compose and added SimpleJdbcExample.java

docker-compose.yaml

@@ -2,7 +2,7 @@ version: "3.7"
 
 services:
   postgres:
-    image: postgres:15.1
+    image: postgres:latest
     restart: always
     environment:
       POSTGRES_DB: idatt1005-db
@@ -11,8 +11,7 @@ services:
     ports:
       - 5432:5432
     volumes:
-      - db:/var/lib/postgresql/data
+      - db_data:/var/lib/postgresql
 
 volumes:
-  data1-1:
-  db: { }
+  db_data:

src/main/java/no/ntnu/idatx1005/demo/dbexample/SimpleJdbcExample.java

@@ -0,0 +1,70 @@
+package no.ntnu.idatx1005.demo.dbexample;
+
+import java.sql.*;
+
+public class SimpleJdbcExample {
+
+    private static String DB_NAME = "idatt1005-db";
+    private static String DATABASE_URL = "jdbc:postgresql://localhost:5432/" + DB_NAME;
+    private static String username = "idatt1005user";
+    private static String password = "idatt1005password";
+
+    public static void main(String[] args) {
+
+        try {
+            // get database connection
+            Connection connection = DriverManager.getConnection(DATABASE_URL, username, password);
+            addUser(connection);
+            getUsers(connection);
+
+            //modifyUser(connection);
+            //deleteUser(connection);
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    private static void getUsers(Connection connection) throws SQLException {
+        // define a statement with SQL query (get data)
+        PreparedStatement preparedStatement = connection.prepareStatement("SELECT * FROM userinfo");
+
+        // execute statement and get resultset
+        ResultSet resultSet = preparedStatement.executeQuery();
+
+        //iterate over resultset
+        while (resultSet.next()) { // moves its cursor in a forward direction
+            System.out.println("userId:"+resultSet.getInt(1)+
+                    " Username:"+resultSet.getString(2));
+        }
+    }
+
+    private static void deleteUser(Connection connection) throws SQLException {
+        //  define a statement with SQL query (to add a new record)
+        String sql = "DELETE FROM userinfo WHERE \"userId\" = ?";
+        PreparedStatement preparedStatement = connection.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS);
+        preparedStatement.setInt(1, 100);             // userId to update
+        int rowsDeleted = preparedStatement.executeUpdate();
+        System.out.println("Rows deleted: " + rowsDeleted);
+    }
+
+    private static void modifyUser(Connection connection) throws SQLException {
+        //  define a statement with SQL query (to add a new record)
+        String sql = "UPDATE userinfo SET \"username\" = ? WHERE \"userId\" = ?";
+        PreparedStatement preparedStatement = connection.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS);
+        preparedStatement.setString(1, "John Doe");  // new username
+        preparedStatement.setInt(2, 100);             // userId to update
+        int rowsUpdated = preparedStatement.executeUpdate();
+        System.out.println("Rows updated: " + rowsUpdated);
+    }
+
+    private static void addUser(Connection connection) throws SQLException {
+        //  define a statement with SQL query (to add a new record)
+        String sql = "INSERT INTO userinfo (\"userId\", \"username\") VALUES (?, ?)";
+        PreparedStatement preparedStatement = connection.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS);
+        preparedStatement.setObject(1, 100, Types.OTHER);
+        preparedStatement.setString(2, "John");
+        preparedStatement.executeUpdate();
+    }
+
+
+}