Seven Customer Databases – An Integration Problem
You are working as a consultant for Integrated Trading, a financial services firm.
They have merged several times, and they have brought you in to straighten out their customer database problem. They have too many customer databases, one for each of their services. Many of the customers overlap several services. They want you to design a system that will integrate the databases.
Their problem scenario is the following:
Last week, Mellon bank called in to trade an equity portfolio. After they provided all the information to make the trade, they said they also wanted to sell some convertible debt. They were transferred to the convertible desk – the salesperson asked them all over again for their customer information.
They were really annoyed, and complained that not only do they need to explain themselves every time they are reconnected in the company, but that their bills, reports, and salespeople are all different across the five different services they buy from Integrated Trading. They threatened to bring their business elsewhere unless they are treated as a single customer.
You have found out that the customer databases are just one part of the issue. Each database is controlled by a complex customer application that involves large amounts of custom code, ranging in size from 150,000 lines of Java to 1,000,000 lines of COBOL. You have been told to come with a solution that does not involve changing this legacy code.
A previous consulting engagement has revealed the following. 40% of customers only use one service. But 30% use two services, and 30% use three or more services.
From a strategic perspective, you would like to seamlessly offer customers additional services, and thus you can justify the expense of solving the integration problem not only because it will retain the larger customers, but also because it can help generate more revenue.
There are more details on the customers who use more than one service. In most cases, they do not call in and use both services on the same call. They may call back later in the day, or on another day.
Customer information does not change very much. Adding a new customer to the database has to be a relatively quick process, or you lose the customer. After the customer is added, usually there are less than 12 changes year.
The databases themselves all have different ways of representing a customer – some as a number, others as a set of characters. Some databases have hierarchies of customers – for example, Mellon, and subcategories of equity and fixed income.

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Other databases are flat, listing each contact as separate customer –for example,
Mellon Equity, Mellon Fixed Income.
Now that you understand the problem, play out the various situations as described earlier and use sequence diagram or structure diagram to help you sketch out the dynamic of the interactions.
Don’t forget your iterations SPF and the environment.
As you move from the problem space to the solution space, try different things using different integration mechanisms to address the problem at hand. A good way to portray these 7 databases is to look at this diagram as a start.

Now create several sequence diagrams that could solve the problem:

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Did you put anything in between the application and the original databases? If so, try an alternative design that does not insert anything between the application and the original databases.

Create a new textual scenario – a solution scenario – in which a customer calls into the owners of one database, and wants to know information from yesterday stored in a different database.

Show a sequence diagram for the above, based on your proposed solution

Show a structural diagram for your solution

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Mark on the structural diagram above the elements of the original system that would have to change, and the components that are new.
Suppose a new analyst in Integrated Trading wants to see all the information about an existing customer across all services. Will your design allow for that? Where would the analyst interface with the database or databases?

You should now have the basic materials to build the poster.

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