ER diagram¶

erDiagram
    assets {
        int id
        string doc_id
        string name
    }
  hardpoints {
    int id
    string doc_id
    string name
  }
  devices {
    int id
    string doc_id
    string serial_number
  }
  signals {
    int id
    string doc_id
    string name
  }
  signal_data {
    int signal_id
    timestamptz t
    real y
  }
  assets ||--o{ hardpoints : have
  hardpoints |o--o{ signals : have
  devices |o--o{ signals : have
  signals ||--o{ signal_data : data

• for all tables, except for signal_data, id is a primary key and doc_id is a candidate key.
• assets are things in the real world that are monitored. e.g. Pumpjack
• hardpoints are where devices can be installed on assets. It is usually a monitoring point of interest. e.g. Tubing
• signals is synonymous with sensors. It represents a time-series.
• signal_data is the actual time-series data associated with a signal.
• devices is usually the actual hardware that is collecting data. Note that it can have one or more sensors/signals.
  • serial_number is a candidate key.
• the primary key for signal_data is (signal_id, t).