# basic-jdbc

**Repository Path**: java-lesson/basic-jdbc

## Basic Information

- **Project Name**: basic-jdbc
- **Description**: No description available
- **Primary Language**: Unknown
- **License**: MIT
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2026-04-06
- **Last Updated**: 2026-04-06

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# Basic JDBC Project

## Overview

This is a basic Java JDBC (Java Database Connectivity) learning project that demonstrates how to connect to a MySQL database using the JDBC API and perform basic CRUD (Create, Read, Update, Delete) operations.

## Technology Stack

- **Java**: JDK 26
- **Database**: MySQL
- **JDBC Driver**: MySQL Connector/J 9.4.0
- **Build Tool**: Maven

## Project Structure

```
basic-jdbc/
├── src/main/java/
│   ├── connection/          # Database connection examples
│   │   ├── BasicJDBC.java   # Basic connection (manual resource closing)
│   │   └── AutoJDBC.java    # Automatic resource management (try-with-resources)
│   └── CRUD/                # CRUD operation examples
│       ├── Create.java      # Insert data
│       ├── Read.java        # Query data
│       ├── Update.java      # Update data
│       └── Delete.java      # Delete data
└── pom.xml                  # Maven configuration file
```

## Prerequisites

- JDK 26 or higher
- MySQL database (this project uses the sakila sample database)
- Maven 3.x

## Configuration

### Database Connection Settings

All examples use the following default configuration:

- **Host**: 127.0.0.1 (localhost)
- **Port**: 3306
- **Database**: sakila
- **Username**: root
- **Password**: root
- **Encoding**: UTF-8

**Note**: Please modify the connection parameters according to your MySQL configuration before use.

## Running the Examples

### 1. Compile the Project

```bash
mvn clean compile
```

### 2. Run Individual Examples

```bash
# Run basic connection example
mvn exec:java -Dexec.mainClass="connection.BasicJDBC"

# Run automatic resource management example
mvn exec:java -Dexec.mainClass="connection.AutoJDBC"

# Run CRUD operations
mvn exec:java -Dexec.mainClass="CRUD.Create"
mvn exec:java -Dexec.mainClass="CRUD.Read"
mvn exec:java -Dexec.mainClass="CRUD.Update"
mvn exec:java -Dexec.mainClass="CRUD.Delete"
```

## Features

### Database Connection

#### BasicJDBC.java
Demonstrates the traditional JDBC connection approach, requiring manual closing of Statement and Connection resources in a finally block.

#### AutoJDBC.java
Demonstrates the modern approach using try-with-resources statements for automatic resource management, resulting in cleaner and safer code.

### CRUD Operations

#### Create.java
Inserts new records into the actor table, demonstrating INSERT operations.

#### Read.java
Queries all records from the actor table, demonstrating SELECT operations and ResultSet iteration.

#### Update.java
Updates records in the actor table, demonstrating UPDATE operations.

#### Delete.java
Deletes records from the actor table, demonstrating DELETE operations.

## Known Issues and Improvement Suggestions

### ⚠️ Security Issues

- **SQL Injection Risk**: All examples use Statement with concatenated SQL, which is vulnerable to SQL injection. PreparedStatement should be used instead.
- **Hardcoded Credentials**: Database username and password are hardcoded in the source code. Configuration files or environment variables should be used.

### 🔧 Code Quality Issues

- **Improper Exception Handling**: 
  - Exceptions are only printed without proper error handling
  - BasicJDBC throws RuntimeException directly, causing program crashes
  
- **Resource Leak Risk**: The resource closing approach in BasicJDBC is verbose and error-prone

- **Missing Return Value Validation**: The return value of execute() method is not checked

### 💡 Best Practice Recommendations

- **Missing Transaction Management**: Transaction management should be considered for write operations

- **Hardcoded SQL**: SQL statements should be externalized to configuration files

- **Missing Logging Framework**: Using System.out.println and printStackTrace; SLF4J + Logback is recommended

## Improvement Directions

- Use PreparedStatement to prevent SQL injection
- Introduce configuration files for database connection parameters
- Add proper logging
- Implement connection pooling (e.g., HikariCP)
- Add unit tests
- Use ORM frameworks (e.g., MyBatis or JPA/Hibernate)

## License

This project is for learning and educational purposes only.

## Contact

Feel free to open an issue if you have any questions or suggestions.