JDBC Application Development

Introduction to JDBC

• JDBC (Java Database Connectivity) is part of JSC module.
• Provides rules and guidelines to develop JDBC driver software.
• JDBC driver acts as a bridge between Java applications and database software.

Persistence Logic

• Persistence logic refers to the logic that interacts with a database to manipulate data.
• CRUD operations are performed:
  • Create - Insert records
  • Read - Select records
  • Update - Modify records
  • Delete - Remove records
• In Indian culture, CRUD is referred to as "CURD" or "Crude" due to local terminology.

Importance of CRUD Operations

• Essential in service sectors like banking and hospitals.
• Example:
  • Inserting a new patient's record.
  • Updating phone number when a patient changes contact.
  • Selecting patient details before treatment.
  • Deleting records post-treatment.

Non-Technical Users and JDBC

• Non-technical users cannot write SQL queries directly.
• JDBC is used to develop user-friendly front-end applications (with buttons, text boxes) to perform database operations without needing SQL knowledge.

JDBC Steps in Application Development

1. Load JDBC Driver Class

   • Register the driver with the DriverManager service.
   • Only the driver class that implements java.sql.Driver is necessary.

2. Establish Connection

   • After registering the driver, establish a connection between the Java application and the database.
   • This connection acts as a communication channel (road).

3. Create Statement Object

   • A statement object is necessary to send SQL queries to the database and receive results back.
   • It serves as a vehicle for carrying inputs and outputs between the application and database.

4. Send and Execute SQL Query

   • Use the statement object to send SQL queries (e.g., INSERT, SELECT) to the database.

5. Gather Results and Process

   • After executing a query, gather the results using a ResultSet object.
   • Process the results based on the query executed.

6. Close JDBC Objects

   • It's crucial to close all JDBC objects to free up resources.
   • Open JDBC objects (like connections) should always be closed to avoid resource leaks.

Conclusion & Key Practices

• The importance of closing connections is highlighted through a metaphorical story about a king and his citizens.
• Summary of steps:
  1. Load and register JDBC driver
  2. Establish connection
  3. Create statement object
  4. Send and execute SQL query
  5. Gather and process results
  6. Close all JDBC objects

DriverManager Service

• An invisible built-in service in Java applications that manages JDBC drivers.
• Essential for registering drivers and enabling their use in applications.