# Database API Documentation

## Overview
The database module provides database connection management and basic operations for both PostgreSQL and SQLite databases. Key features include:
- Connection pooling for PostgreSQL
- Context managers for safe connection handling
- Unified interface for both database types
- SQL execution helpers

## Connection Management

### `get_db_connection(db_type='postgres')`
Context manager for database connections.

**Parameters:**
- `db_type`: 'postgres' or 'sqlite' (default: 'postgres')

**Usage:**
```python
with get_db_connection() as conn:
    # Use connection
```

### `get_db_cursor(cursor_factory=None, db_type='postgres')`
Context manager for database cursors with automatic commit/rollback.

**Parameters:**
- `cursor_factory`: Optional cursor factory (e.g., psycopg2.extras.DictCursor)
- `db_type`: 'postgres' or 'sqlite' (default: 'postgres')

**Usage:**
```python
with get_db_cursor() as cursor:
    cursor.execute("SELECT * FROM table")
```

## SQL Execution Helpers

### `execute_query(query, params=None, cursor_factory=None, fetch_one=False, db_type='postgres')`
Executes a query and returns results.

**Parameters:**
- `query`: SQL query string
- `params`: Query parameters (tuple/dict)
- `cursor_factory`: Optional cursor factory
- `fetch_one`: Return single row if True
- `db_type`: Database type

**Returns:**
- Query results (list or single row)

### `execute_update(query, params=None, db_type='postgres')`
Executes an update/insert/delete query.

**Parameters:**
- `query`: SQL query string
- `params`: Query parameters (tuple/dict)
- `db_type`: Database type

**Returns:**
- Number of affected rows

## Initialization

### `init_sqlite_db()`
Initializes SQLite database tables (api_endpoints, api_logs, api_users, api_operations).

## Configuration
Module uses configuration from:
- `DB_CONFIG` for PostgreSQL
- `SQLITE_CONFIG` for SQLite

## Error Handling
- All database operations are wrapped in try/except blocks
- Errors are logged with detailed context
- Connections are automatically returned to pool (PostgreSQL) or closed (SQLite)

## Best Practices
- Always use context managers (`with` statements) for connections/cursors
- For PostgreSQL, prefer connection pooling for better performance
- For complex transactions, use explicit commit/rollback