数据库功能依赖

Question

我试图在我的数据库中找到一些功能依赖，但不知道如何去做。是否有人能够解释如何做到这一点或功能依赖是什么。下面是我创建表格的代码

CREATE TABLE   Customer(
      CustomerID     int  PRIMARY KEY,
      CustomerName   varchar(50)  NOT NULL,
      BillingAddress varchar(400)  default NULL,
      PhoneNumber    varchar(128)  NOT NULL,
      UserEmail     varchar(128) UNIQUE
 )ENGINE=InnoDB DEFAULT CHARSET=latin1;

CREATE TABLE IF NOT EXISTS OrderMaster(
      OrderID             int NOT NULL  PRIMARY KEY,
      CustomerID          int,
      OrderDate           date  NOT NULL,
      PurchaseOrderNumber int
 )ENGINE=InnoDB DEFAULT CHARSET=latin1;




CREATE TABLE OrderItem(
      OrderItemID    int  PRIMARY KEY,
      ProductID      int NOT NULL,
      OrderID        int NOT NULL,
      Quantity       int NOT NULL,
      PricePerUnit   double NOT NULL
)ENGINE=InnoDB DEFAULT CHARSET=latin1;



CREATE TABLE IF NOT EXISTS Product(
       ProductID            int PRIMARY KEY,
       ProductName          varchar(100)  NOT NULL,
       ProductDescription   varchar(100)  NOT NULL,
       SerialNumber         int NOT NULL,
       UnitesInStock        int  NOT NULL,
       UnitsOnOrder         int NOT NULL,
       UnitPrice            double NOT NULL,
       SupplierID           int not NULL
)ENGINE=InnoDB DEFAULT CHARSET=latin1;



CREATE TABLE IF NOT EXISTS SupplySchedule(
       ShippingID        int PRIMARY KEY,
       ShippingMode      varchar(50) NOT NULL

)ENGINE=InnoDB DEFAULT CHARSET=latin1;


CREATE TABLE IF NOT EXISTS Supplier(
        SupplierID       int PRIMARY KEY,
        SupplierName     varchar(40) NOT NULL,
        SupplierAddress  varchar(128) NOT NULL,
        ContactName      varchar(128) NOT NULL


   )ENGINE=InnoDB DEFAULT CHARSET=latin1;