Database

The Database module provides a simple and efficient way to interact with databases with read-only interfaces. It offers table management and query capabilities through a clean and intuitive API.

Overview

The DB module is implemented as a singleton, ensuring a single database connection throughout your application. It provides a clean and intuitive interface for database operations.

Features

Table Management

• List all tables in the database
• Get detailed table structure information
• View field properties and constraints

Data Query

• Flexible query options
• Field selection
• Conditional filtering
• Pagination support
• Sorting capabilities

Examples

Table Operations

// List all tables
const tables = await db.show();
console.log('Available tables:', tables.tables);

// Get table structure
const tableInfo = await db.describe('users');
console.log('Table fields:', tableInfo.fields);

Data Query

// Basic query
const result = await db.select('users', {
    fields: ['id', 'name'],
    where: { status: 'active' },
    limit: 10,
    offset: 0,
    orderBy: 'id',
    order: 'desc'
});

Best Practices

1. Query Optimization

   • Select only needed fields
   • Use appropriate limit and offset for pagination
   • Add proper ordering for consistent results
   • Use specific where conditions to filter data
   • Implement proper error handling:

   try {
       const result = await db.select('users', {
           where: { status: 'active' }
       });
       // ... use result
   } catch (error) {
       console.error('Error querying database:', error);
   }

2. Error Handling

   • Always handle potential database errors
   • Validate table names before queries
   • Check field existence before using them in queries

3. Performance

   • Use appropriate pagination for large datasets
   • Optimize query conditions
   • Cache frequently accessed data
   • Monitor query performance

4. Data Validation

   • Validate query parameters

Limitations

• The module currently supports read operations only
• Complex queries (joins, subqueries) are not supported
• No direct support for data modification operations