1. What is JDBC?

JDBC (Java Database Connectivity) is an API that enables Java applications to interact with databases. Its primary purpose in enterprise applications is to provide a standard interface for connecting to relational databases, executing SQL queries, and retrieving results. JDBC acts as a bridge between Java code and various databases, ensuring portability and flexibility.

How JDBC Facilitates Interaction:

• Java applications use JDBC classes and interfaces to establish a connection with a database.
• Developers can execute SQL commands (SELECT, INSERT, UPDATE, DELETE) using JDBC.
• Results are retrieved and processed in Java, enabling dynamic data-driven applications.

Example:

Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydb", "user", "password");
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery("SELECT * FROM employees");
while(rs.next()) {
    System.out.println(rs.getString("name"));
}

This code connects to a MySQL database, executes a query, and prints employee names.

2. Describe the JDBC Architecture

JDBC architecture defines how Java applications communicate with databases. There are two main architectures:

Two-Tier Architecture

• The Java application communicates directly with the database using JDBC.
• Suitable for simple, small-scale applications.

Diagram:

Java Application <--> JDBC Driver <--> Database

Three-Tier Architecture

• Introduces a middle tier (application server) between the client and the database.
• Suitable for large-scale, distributed enterprise applications.

Diagram:

Java Application <--> Application Server <--> JDBC Driver <--> Database

Differences \& Use Cases:

• Two-Tier: Direct, simple, less scalable; best for desktop or small apps.
• Three-Tier: More scalable, secure, supports business logic in the middle tier; used in web and enterprise systems.

3. Main Components of JDBC

The four major components are:

1. JDBC Drivers: Enable Java applications to communicate with different databases.
2. DriverManager: Manages a list of database drivers and establishes connections.
3. Connection: Represents a session with a specific database.
4. Statement: Used to execute SQL queries against the database.

Role of DriverManager: Acts as a factory for database connections, selecting the appropriate driver for the requested database.

Role of Test Suite: A set of tools and tests to verify JDBC driver compliance and correctness.

4. JDBC Classes and Interfaces

Five important JDBC classes/interfaces:

5. Key Features of JDBC

• Database Independence: Works with any database supporting a JDBC driver, making applications portable.
• SQL Support: Allows execution of SQL statements from Java, enabling dynamic data operations.
• Exception Handling: Robust error handling using exceptions, improving reliability and debugging.

6. Comparison of JDBC Driver Types

7. When to Use Each JDBC Driver Type

• Type-1: For quick prototyping or legacy systems where ODBC is already in use.
• Type-2: When performance is critical and native libraries are available for the target platform.
• Type-3: In enterprise environments with a middleware server managing database access.
• Type-4: Preferred for most modern applications due to its speed, portability, and ease of deployment.

These solutions provide a comprehensive overview of JDBC concepts, architecture, components, features, and driver types relevant for enterprise Java applications.