feat(jdbc-sqlite): add DataBase demo to fetch and display student records

What
- Added `DataBase` example under Section28JDBCusingSQLite.
- Establishes a connection to `univ.db` using SQLite JDBC driver.
- Executes a `SELECT * FROM students` query via `Statement`.
- Iterates over `ResultSet` to print all student details:
  - Roll number
  - Name
  - City
  - Department number

Why
- Demonstrates the use of plain `Statement` for executing static SQL queries.
- Provides a foundational example for working with `ResultSet` in JDBC.
- Useful for quick table dumps or when parameter binding is not required.
- Serves as a stepping stone before introducing `PreparedStatement`.

How
- Loaded SQLite JDBC driver with `Class.forName("org.sqlite.JDBC")`.
- Opened connection using `DriverManager.getConnection()`.
- Created `Statement` to run SQL queries.
- Executed `executeQuery("SELECT * FROM students")`.
- Used `rs.next()` loop to retrieve column values (`getInt`, `getString`).
- Printed records in a pipe-delimited format.
- Closed `Statement` and `Connection` to release resources.

Key Notes
- `Statement` is best for static SQL with no dynamic parameters.
- `ResultSet` cursor moves row by row; must check with `rs.next()`.
- Always close JDBC resources to prevent memory leaks.
- For dynamic queries, prefer `PreparedStatement`.

Real-life Applications
- Fetch all records for reporting modules.
- Generate tabular views in admin dashboards.
- Quick debugging tool to verify table contents.
- Base implementation for migrating data to another system.

Future Improvements
- Replace `Statement` with `PreparedStatement` for parameterized queries.
- Use try-with-resources for automatic resource cleanup.
- Format output into aligned tables for better readability.
- Extend functionality to filter records (e.g., by deptno or city).

Signed-off-by: https://github.com/Someshdiwan <[email protected]>

Author: Someshdiwan

Section28JDBCusingSQLite/JAVA SQL Interfaces/src/DataBase.java

@@ -7,16 +7,16 @@ public class DataBase {
     public static void main(String[] args) throws Exception {
         Class.forName("org.sqlite.JDBC");
 
-        //Connection is extablish.
-        Connection con = DriverManager.getConnection("jdbc:sqlite:C:/sqlite/univ.db");
-        System.out.println("✅ Connection Established!");
+        Connection con = DriverManager.getConnection(
+                "jdbc:sqlite:/Users/somesh/Java SE/JavaEvolution-Learning-Growing-Mastering/Section28JDBCusingSQLite/univ.db"
+        );
 
+        System.out.println("Connection Established!");
 
-        //Connection object and con is an interface.
-        //con.
+        //Connection object and con are an interface.
         Statement stm = con.createStatement();
 
-        //entire table name means the output of table we stored.
+        //the entire table name means the output of the table we stored.
         ResultSet rs = stm.executeQuery("SELECT * FROM students");
 
         while (rs.next()) {
@@ -25,8 +25,8 @@ public static void main(String[] args) throws Exception {
             System.out.print(rs.getString("city") + " ");
             System.out.println(rs.getInt("deptno")+" | ");
         }
-        stm.close(); //close the statement.
-        con.close(); //Connection close.
-        System.out.println("✅ Connection Closed.");
+        stm.close();
+        con.close();
+        System.out.println("Connection Closed.");
     }
 }