Making an ERD

Topics: Tax File Number, Currency, Given name Pages: 7 (952 words) Published: April 18, 2015
COIT20247: Database Design and Development
Term1, 2015
Assessment 1 - Systems Development

Lecturer: Umapathy Venugopal
Tutor: Umapathy Venugopal

Prepared by:
William Rogers

Table of Contents

Business Rules4
List of assumptions4
Entity and Attribute Definitions:5
Reference List7

Business Rules

All staff must record their full name, address, and phone numbers as well as be given a unique employee ID. Analysts are required to give their expertise while managers and administrative staff must give their qualifications. Recommendations made by their research must be given with a recommendation to buy, sell, or hold, with a brief reason why. Recommendations are time sensitive, so recommendations must come with a date and time. Currencies are described by code, name, interest rate, and rating (i.e. S&P or Moody’s). Managers may manage multiple portfolios.

Every portfolio has its own ID.
Portfolios can be regarded as an account and only associated to one client. The portfolio must contain data for available cash, and data for trades for each individual portfolio. Trade details include the amount traded, the trade mode, and the exchange rate. There are “normally” three client types that must be recorded along with their details such as their client ID, address, and phone numbers. Individuals must give their TFN, businesses must give their ABN, and trustees must give the trust account number.

List of assumptions

1.) I did not add a double line to the employee sub-types because I didn’t feel that three employee types would be sufficient. Most likely for this type of business there would be other employees like a secretary or IT staff. 2.) I placed a d in the circle for subtypes to indicate subtypes as discriminators. Every employee most likely has a specific position. 3.) I created an associated entity between Portfolio and Currency to resolve a many to many relationship. Inside a placed attributes that would be specific to individual trades that are needed for the database. 4.) I left the relationship for portfolio many to one client because I thought it might be possible that a client might have separate portfolios. 5.) I did not put a double line to the subtypes of Client. In the specification the word, “normally” was used to describe use of the three given client types which leads me to believe that it is possible there are other possible client types. 6.) I also made the subtypes for clients discriminatory because I don’t believe these subtypes overlap at all. Although, I do know trusts can be extremely complicated so it would be good to have open communication with the company. 7.) I created an extra entity for storing information about Trusts. I thought this would be a logical addition to the database for a few reason. I saves space by not forcing the re-entry of trust information for multiple members of a trust. It also makes it easier to query for other members of the same trust. Last, it prevents a situation where one trustee is a member of more than one trust.

Entity and Attribute Definitions:

Entity:Employee – This entity contains information about employees of the company which includes:
Attributes:Employee ID – The unique ID given to each employee
Full Name – Last name and given names
Address – The employee’s address
Phone Number – A list of all contactable phone numbers
Subtype Entities:Administrator – An entity for addition attributes of an administrator. Attributes:Position – The type or department of this particular administrator.
Qualifications – A list of all the qualifications of this analyst.
Analyst – An entity for additional attributes of an analyst
Attributes:Expertise – The expertise of this analyst.
Portfolio Manager – An entity for additional attributes of a portfolio manager. Attributes:Qualifications – A list of all the qualifications of this portfolio...
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