Entity Relationship Diagram

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Entity Relationship Diagram
The bellow diagram is what is refered to as an "Entity Relationship Diagram". Its purpose is to show the relationship between different data in the hotel management program , and the actions that are performed on it. And how data from different objects relate to each other. Legend

The Data Entities represent data that will need to be stored on the system, in general terms. The Relationships represent actions that will occur to the Data Entities, or Weak Entities. The Weak Entities represent data that does not exist, except in relation to a Data Entity.

Data Dictionary
Below is a data dictionary used to demostrate how data will be represented in the computer system, and how different modules are inter related.

Access Level = (Front Desk) + (Kitchen) + (Management)
* An access level which denotes exactly which areas, a user has access to.* Amount Paid= $ + INT + '.' + [00 | 01 | .. | 99]
The amount the customer has actually paid.
Arrival Date = Date
* Represents the date the cutomers arrived.*
Balance $ + INT + '.' + [00 | 01 | .. | 99]
The amount remaining for the customer to pay.
Bill to = Room Number
* A valid room number in the hotel to bill a some to.*
Bus. Phone = Phone Number
* Represents the bussiness phone number of the customer.*
Calendar Day = Date + {Room}
* Represnts all of the days on the calendar, along with which rooms are booked for that day.* Category = [Single | Double | Triple]
* A category represents the size of a room.*
City = STRING(64)
* Represents the name of a city.*
Country = STRING(64)
* Represents the name of a country.*
Cost of Phone Call= $ + INT + '.' + [00 | 01 | .. | 99]
* The cost of an outgoing phone call.*
Credit Card Number [0000 0000 0000 0000 | 0000 0000 0000 0001 | .... .... .... .... | 9999 9999 9999 9999] * Represents a credit card number.*
Customer Info = Guest Name + Room Number + Arrival Date + Departure Date + Representing + Mailing Address + Bus. Phone + Home Phone + Number Of Occupants + Additional Occupants + Vehicle Description + Special Instructions * Represents all of the infomration about customers in a certain room.* Date = [01 | 02 | .. | 12] + \ + [01 | 02 | .. | 31] + \ + [1996 | 1997 | .... | 3000] * Represents the date in month/day/year format.*

Delivery Time = Time + Date
* The Time at which a room service request should be delivered.* Departure Date = Date
* Represents the date the customer is expected to leave.*
Employee = Employee Name + Password + Employee Number + Access Level * Represents all of the information on a current employee.*
Employee Name = Name
* Represents the name of an Employee *.
Employee Number = INT
* A unique employee number.*
First Name = STRING (30)
* Represents A Persons First Name.*
Food Description = STRING(256)
* A Field used to Describe a Menu Item.*
Food Item = STRING(32)
* A Field which represents dish on the menu item.*
Front Desk Messages = {Message}
* Represents all of the messages currently at the front desk.* Guest Bill = Guest Name + (Room Service Bills) + (Phone Service) + Arrival Date + Departure Date + Room Rate + Room Number + Amou nt Paid + Balance + Method Of Payment + (Credit Card Number) + Employee Number * Represents all of the information needed to generate a bill fo r a guest.* Guest Name = Name

*Represents the name of a Guest*
Handicapped = [Yes | No]
* This field determines if the room is Handicap Accessible.* Home Phone = Phone Number
* Represents the home phone number of the customer.*
Hotel Rooms = {Room}
* Represents all of the rooms in the hotel.*
Last Name = STRING (30)
* Represents A Persons Last Name.*
License Plate = {[ 0 | 1 | .. | 9 | A | B | .. | Z]}^9
* Represents the license plate of a vehicle.
List Of Food Entries = {Menu Item}
* A particular order of some items off of the menu.*
Mailing Address = Street Address + City + Province + Country + Zip Code * Represents A postal mailling addres.*
Menu = {Menu...
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