docs(jdbc): add detailed explanation of JDBC program flow and core interfaces

What
- Documented the step-by-step flow of how a Java program interacts with a database using JDBC.
- Explained the role of each core `java.sql` interface:
  1. `Class.forName()` → dynamically loads JDBC driver.
  2. `DriverManager` → manages drivers and creates connections.
  3. `Connection` → represents active session with database.
  4. `Statement` → executes SQL queries/updates.
  5. `ResultSet` → processes query results.
- Added a complete runnable example demonstrating connection to SQLite (`univ.db`) and retrieving data from `students` table.

Why
- JDBC is fundamental for Java-based database applications, yet its flow can be confusing to beginners.
- Provides clarity on how each component fits into the lifecycle: load driver → connect → query → process → close.
- Reinforces importance of closing resources to prevent memory leaks and ensure DB reliability.

How
- Broke explanation into sections: purpose, usage, importance of each interface.
- Showed step-by-step process (load → connect → create → execute → process → close).
- Provided example with `Class.forName`, `DriverManager.getConnection`, `Statement.executeQuery`, and iterating over `ResultSet`.

Key Points
- **Driver loading** via `Class.forName()` registers the JDBC driver with `DriverManager`.
- **Connection** is mandatory for all SQL operations.
- **Statement** sends SQL commands; `executeQuery` for `SELECT`, `executeUpdate` for `INSERT/UPDATE/DELETE`.
- **ResultSet** is a cursor that moves row by row (`rs.next()`).
- **Closing resources** (`rs.close()`, `stmt.close()`, `con.close()`) is critical for proper cleanup.

Real-life Applications
- Web applications (e.g., Spring Boot) connecting to relational databases like MySQL, PostgreSQL, Oracle.
- Enterprise apps retrieving employee, order, or financial data.
- Standalone tools/scripts for reporting, data migration, or auditing.

Notes
- Always use **try-with-resources** or finally blocks to close JDBC resources.
- Use **PreparedStatement** instead of Statement for parameterized queries to improve security and performance.
- JDBC API abstracts database communication → same code can work across different databases by changing the driver.

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

Author: Someshdiwan

Section28JDBCusingSQLite/JAVA SQL Interfaces/Java program interacts with a database.txt renamed to Section28JDBCusingSQLite/JDBC/How a Java program interacts with a database using JDBC (Java Database Connectivity).txt

@@ -1,12 +1,13 @@
 flow of how a Java program interacts with a database using JDBC (Java Database Connectivity).
 
-It highlights the core java.sql interfaces** involved in the process.
+It highlights the core java.sql interfaces involved in the process.
 
 ---
 
-Components Explained
+Components Explained:
+
 1. Class.forName()
-   - This method dynamically loads the **JDBC driver** for the database you want to connect to.  
+   - This method dynamically loads the JDBC driver for the database you want to connect to.
    - Example:
      Class.forName("org.sqlite.JDBC");
    - Why is it important?
@@ -16,9 +17,9 @@ Components Explained
 
 2. DriverManager
    - It is responsible for managing a list of database drivers.  
-   - Establishes a connection between the **Java application** and the database.
+   - Establishes a connection between the Java application and the database.
    - Example:
-     Connection con = DriverManager.getConnection("jdbc:sqlite:C:/sqlite/univ.db");
+     Connection con = DriverManager.getConnection("jdbc:sqlite:your path:/sqlite/univ.db");
 
    - Why is it important?
      Without DriverManager, your program cannot interact with the database.
@@ -83,7 +84,7 @@ Components Explained
 
 ---
 
-Full JDBC Example
+Full JDBC Example:
 
 import java.sql.*;
 
@@ -116,4 +117,4 @@ public class DatabaseExample {
             e.printStackTrace();
         }
     }
-}
+}