The data dictionary is mentioned in the system development paper, how to write this? What is the difference between the logical design and the physical design of the database? The teacher said that the data dictionary should be written in terms of data items, data structures, data storage, data flow and data processing? Can someone give me an example?
The logical design is as follows:
a table 1 (dish ID, category ID, dish name, introduction to the dish, price, picture)
a table category table 2 (category ID, category name) The
physical design is as follows:
a table 1 dish table: Food
column name Chinese Whether the length of the name data type is allowed to be empty Remarks
FoodID Dish ID Int Not null Primary key
FoodclassID Category ID Int null **
foodName Dish name nvarchar 25 null
FoodIntroduce Dish introduction nvarchar 50 null **
FoodPrice price Float null
FoodImage image varchar 100 null Save the image path
that How to write the data dictionary? The teacher said that the data dictionary should be written in terms of data items, data structures, data storage, data flow and data processing? Can someone give me an example?
Data file: Order details table
File composition: Order serial number Id, order number, menu name, price, quantity, order time
Data item: Order serial number Id
Data type: Integer
Data length: 4
Data item: Order number
Data type: Yes Variable Character Type
Data Length: 50
Data Composition: A+ Date Time
Data Item: Menu Name
Data Type: Variable Character
Data Length: 50
Data Item: Price
Data Type: Integer
Data Length: 4
Data Item: Quantity
Data Type: Integer Type
Data Length: 4
Data Item: Order Time
Data Type: Date Type
Data Length: 8
(2) Data Flow Definition:
Registration
Name: Registration
Brief Description: Administrator Check-in Customer Information
Data Source: Check-in Customer
Data Destination: The data composition of the opening registration
form: Customer name + gender + age + room number + meal order password + certificate type + certificate number + detailed address + telephone + check-in time + check-in days + check-out time
Browse and purchase
name: Browse and purchase
brief description: Customers purchase dishes and add them to the dining car
. Data source: The data of the food purchased by the customer according to the menu goes
to: Process 3 Put it into the dining car
Data composition: dish name + price + quantity