Perform conceptual design for the following case. You must draw in a CROWs FOOT ER diagram developed on paper. You may include, in your CROWs FOOT ER Diagram, specifications that include additional constraints not shown on the diagram. If you believe that you need to make additional assumptions, clearly state them in the specifications.

NoBadStock (NBS), a modeling and simulation company, is planning to build World of Stocks, a new online multi-customer stock simulator. You are in charge of developing the back-end database that supports this simulation.

The simulator allows clients to model online trades. For each client, the simulator needs to store client information including userid, password, email address, first name and last name and zip code. Userids for a client should be unique, while first name and last name do not have to be.

A client can create and manage multiple accounts to play in the simulator. Each account should be tied to the clients userid and have an account number that is unique. The system also needs to capture the accounts current balance, Trade Funds Available, Withdrawal Balance, Margin Available, Total Gain (TG), Total Cost Basis (TCB). An account could belong to one AND ONLY ONE account type.

An account could contain securities. Each security has a symbol, quantity, price, market value, cost basis, and a gain-loss. Each security symbol has a name, a ranking and an asset class type. There are four types of asset classes: Equities, Mutual Funds, Bonds, and Cash. For equities, the system needs to store whether it is International with check constraint of Y or N and if dividend reinvestment is chosen, also with a check constraint of Y or N. For Mutual fund you must store if the fund is taxable with check constraint of Y or N and its load type. A check constraint is used to make sure that the values for load type are Front-end, Back-end, and No-load. For Bonds you must track if the bond is taxable. For cash you must track the interest rate.

It is possible for many accounts to own the same security. Each security refers to items of the same symbol, for example, HD for Home Depot.

Each account also possesses a set of sales known as transactions. Each transaction is made unique by a system generated transaction id. For each transaction, the system records the account, symbol, date, quantity, price, fees, model_date, model_profit. Naturally, multiple accounts could have the same symbol, and one account could have many transactions.

The system allows accounts to be managed by more than one client. Joint tenancy is indicated in the main client table.