ros2-assignments/doc/architecture/managers/DatabaseManager.md

DatabaseManager (assignments::two::DatabaseManager)

Overview

The DatabaseManager class is a PostgreSQL database interface for the ROS2 IMU data collection system. It handles all database operations including connection management, table creation and data storage.

Implementation Details

Dependencies

• pqxx: Modern C++ PostgreSQL library for database connectivity
• rclcpp: ROS2 C++ client library for logging
• ConfigManager: Configuration manager for database settings

Key Components

Constructor

DatabaseManager(rclcpp::Logger logger)

• Initializes the database manager with ROS2 logging
• Creates a ConfigManager instance for configuration handling
• Automatically calls init_database() to establish connection and setup

Connection Management

bool connect(const std::string& connection_string)

Returns true on successful connection, false on failure

• Establishes connection to PostgreSQL database using connection information from the config TOML
• Connection string format: "host=localhost port=5432 dbname=imu_data user=postgres password=postgres"

bool is_connected() const

Returns true if connection exists and is open

• Check for active database connection status

Database Initialization

void init_database()

• Database setup process
• Loads configuration from ConfigManager
• Establishes connection using configuration settings
• Creates necessary tables and inserts sample data
• Error handling for configuration and connection failures

void create_tables()

• Creates all required database tables using SQL queries from SQLQueries.hpp
• Tables created:
  • imu_data: IMU sensor readings with linear acceleration and angular velocity data
• Uses transactions for atomic table creation

Data Operations

IMU Data Storage

bool store_imu_data(double linear_accel_x, double linear_accel_y, double linear_accel_z, double angular_vel_x, double angular_vel_y, double angular_vel_z)

Returns true on successful storage, false on failure

• Stores IMU sensor readings in the database
• Parameters:
  • linear_accel_x: Linear acceleration on X-axis
  • linear_accel_y: Linear acceleration on Y-axis
  • linear_accel_z: Linear acceleration on Z-axis
  • angular_vel_x: Angular velocity around X-axis
  • angular_vel_y: Angular velocity around Y-axis
  • angular_vel_z: Angular velocity around Z-axis
• Automatically adds timestamp on insertion

Logging

• Uses ROS2 logger with [DBS] prefix for database operations
• Different log levels:
  • INFO: Successful operations, connection status
  • ERROR: SQL errors, connection failures, configuration issues
  • WARN: Non-critical issues, missing configurations

Usage Examples

Basic Database Setup

// Create DatabaseManager with ROS2 logger
DatabaseManager db_manager(node->get_logger());

// Check connection status
if (db_manager.is_connected()) {
    // Database ready for operations
    bool success = db_manager.store_imu_data(1.2, -0.5, 9.8, 0.01, 0.02, 0.03);
    if (success) {
        RCLCPP_INFO(logger, "IMU data stored successfully");
    }
}