erDiagram
    CustomerCustomerDemo }o--|| CustomerDemographics : have
    CustomerCustomerDemo }o--|| Customers : through
    Employees ||--|| Employees : "reports to"
    Employees ||--o{ EmployeeTerritories : through
    Orders }o--|| Shippers : "ships via"
    "Order Details" }o--|| Orders : have
    "Order Details" }o--|| Products : contain
    Products }o--|| Categories : in
    Products }o--|| Suppliers : "supplied by"
    Territories ||--|| Regions : in
    EmployeeTerritories }o--|| Territories : have
    Orders }o--|| Customers : place
    Orders }o--|| Employees : "sold by"


    Categories {
        int CategoryID PK
        string CategoryName
        string Description
        blob Picture
    }
    CustomerCustomerDemo {
        string CustomerID PK, FK
        string CustomerTypeID PK, FK
    }
    CustomerDemographics {
        string CustomerTypeID PK
        string CustomerDesc
    }
    Customers {
        string CustomerID PK
        string CompanyName
        string ContactName
        string ContactTitle
        string Address
        string City
        string Region
        string PostalCode
        string Country
        string Phone
        string Fax
    }
    Employees {
        int EmployeeID PK
        string LastName
        string FirstName
        string Title
        string TitleOfCourtesy
        date BirthDate
        date HireDate
        string Address
        string City
        string Region
        string PostalCode
        string Country
        string HomePhone
        string Extension
        blob Photo
        string Notes
        int ReportsTo FK
        string PhotoPath
    }
    EmployeeTerritories {
        int EmployeeID PK, FK
        int TerritoryID PK, FK
    }
    "Order Details" {
        int OrderID PK, FK
        int ProductID PK, FK
        float UnitPrice
        int Quantity
        real Discount
    }
    Orders {
        int OrderID PK
        string CustomerID FK
        int EmployeeID FK
        datetime OrderDate
        datetime RequiredDate
        datetime ShippedDate
        int ShipVia FK
        numeric Freight
        string ShipName
        string ShipAddress
        string ShipCity
        string ShipRegion
        string ShipPostalCode
        string ShipCountry
    }
    Products {
        int ProductID PK
        string ProductName
        int SupplierID FK
        int CategoryID FK
        int QuantityPerUnit
        float UnitPrice
        int UnitsInStock
        int UnitsOnOrder
        int ReorderLevel
        string Discontinued
    }
    Regions {
        int RegionID PK
        string RegionDescription
    }
    Shippers {
        int ShipperID PK
        string CompanyName
        string Phone
    }
    Suppliers {
        int SupplierID PK
        string CompanyName
        string ContactName
        string ContactTitle
        string Address
        string City
        string Region
        string PostalCode
        string Country
        string Phone
        string Fax
        string HomePage
    }
    Territories {
        string TerritoryID PK
        string TerritoryDescription
        int RegionID FK
    }