Evidencias acerca del efecto de la actuación sindical sobre la economía

them and other project notes in a folder or notebook of some kind. It is always useful to be able to review your notes and revisit why you made the decisions you did. You may find that you need to modify the original ideas based on later evidence.

Things We Have Done

In this chapter we have

• revisited the problem domain by reviewing the issues with the current system

• reviewed the business rules for the tutoring database • reviewed the materials collected in the previous chapters and

extracted nouns that may become entities and attributes

• organized the nouns into preliminary entities and attributes

• looked for attributes that could serve as candidate keys, that is, attributes that could potentially work as primary keys for the entities

Vocabulary

Match the definitions to the vocabulary words:

1. User access 2. Server 3. Surrogate key 4. Actor

— a. A program that requests a service

— b. A key that consists of more than one attribute

— c. A program in SQL that is triggered by a database event — d. A program that offers a service to requesting programs

— e. A key based on one or more “natural” attributes of an entity of topic headings do you find?

2. Look up two or more definitions for “Business Rules.”

3. Look up an article on the Web that discusses natural versus surrogate keys in databases. Which does the author prefer?

4. What are some additional plusses or minuses of each?

Practices

Use the following scenario for each of the practice exercises:

You have been asked to build a database for a pet foster and adoption shelter. The agency is a nonprofit that takes in stray or abandoned pets and places them with foster caregivers until the pet is adopted. Foster caregivers are volunteers, though they must first be screened. The database needs to track all animals in its care, their species, breed, name, and condition. It also needs to track all approved foster caregivers and the animals currently in their care. Foster caregivers are also supposed to turn in monthly reports on the animals in their care. The database also needs to track the adoptions of the animals.

Currently, volunteers come into the shelter and fill out a paper form. After a background check, they are added to a file.

Some volunteers complain that they are never contacted again.

The shelter staff admits, they tend to go with foster caregivers they know, and some people get forgotten in the file. The shel-ter has also occasionally lost track of an animal in fosshel-ter care when the caregiver failed to turn in the monthly reports.

Another recurring problem is that when someone comes into the shelter looking to adopt, it is not always easy or even possi-ble to let them know about all the animals availapossi-ble for adoption.

Ideally, the shelter would like people to be able to register as a volunteer online. They would like to be able to call up a list of all available foster volunteers. They would also like to be able to pull up all the animals of the kind a potential adopter is inter-ested in and know exactly where those animals are and who is caring for them.

1. Make a list of some of the major issues with the current sys-tem used in the shelter.

2. Identity who the major actors are and list them.

3. Would animals be an actor in this database? Explain why or why not.

4. Make a list of requirements for each of the actors showing how he or she would interact with the database.

5. Make a list of business rules for the shelter.

The Wild Wood Management team is ready to see some results.

You have a meeting with them at the end of the week. It is time to analyze and organize all the information. Look back at the material from the last chapters.

1. Make a list of issues with the current system.

2. Make a list of the database requirements for each stake-holder involved in the database.

3. Make a list of business rules.

4. List some major security rules for the database.

5. Take a look at each of the forms, and make a list of all the nouns in them. Do the same for the interview, the ques-tionnaire, and the Job Shadow Report. Then set up some preliminary entities and attributes.

6. Identify some candidate keys.

7. Documentation : Store the list of the requirements and business rules in your database notebook.

VINCE’S VINYLS

You are eager to show Vince some progress on the database.

You sit down to analyze all the materials you have gathered to see if you can make some sense of them. Make sure you review the material in the previous two chapters.

1. Make a list of issues with the current system.

2. Make a list that shows the database requirements for each stakeholder involved in the database.

3. Make a list of business rules.

4. List some major security rules for the database.

5. Take a look at each of the forms, and make a list of all the nouns in them. Do the same for the interview, the ques-tionnaire, and the Job Shadow Report. Then set up some preliminary entities and attributes.

6. Identify some candidate keys.

7. Documentation : Store the list of the requirements and business rules in your database notebook.

GRANDFIELD COLLEGE

It is imperative that the college get the software tracking database online as soon as possible. You have assured the management team that you will be able to show some progress very soon. It is time to set down and review all the forms and materials.

1. Make a list of issues with the current system.

2. Make a list of the database requirements for each stake-holder involved in the database.

3. Make a list of business rules.

4. List some major security rules for the database.

5. Take a look at each of the forms, and make a list of all the nouns in them. Do the same for the interview, the ques-tionnaire, and the Job Shadow Report. Then set up some preliminary entities and attributes.

6. Identify some candidate keys.

7. Documentation : Store the list of the requirements and business rules in your database notebook.

WESTLAKE RESEARCH HOSPITAL

The drug study is set to begin in just a few months’ time. It is important to make some progress toward the database. It is time to gather all the materials you have collected and try to make some sense of them.

1. Make a list of issues with the current system.

2. Make a list of the database requirements for each stake-holder involved in the database.

3. Make a list of business rules.

4. List some major security rules for the database.

5. Take a look at each of the forms, and make a list of all the nouns in them. Do the same for the interview, the ques-tionnaire, and the Job Shadow Report. Then set up some preliminary entities and attributes.

6. Identify some candidate keys.

7. Documentation : Store the list of the requirements and business rules in your database notebook.

SUGGESTIONS FOR SCENARIOS

Review all the documents and interviews from the last chapter.

It will probably be necessary to talk with your instructor or other students to answer some of the questions about you sce-nario that have not yet been answered. A certain amount of invention is expected here.

Look at the requirements in terms of each user or actor. It is much easier to do it this way rather than trying to just make a general list of requirements. The actor gives you a clearer focus on what the database needs to do in a particular instance. The same holds true of the database security. It is much easier to understand in terms of each actor’s access needs.

When making the initial list of nouns, don’t try to dis-tinguish between entities and attributes. Just list them in the order you encounter them. Save the analysis until you are done.

When you do the analysis, remember entities are major themes or elements. They will tend to stand out. If you find a lot of words clustered around a single topic, that topic is likely the entity and the words clustered around it are probably attributes.

It is good to remember that this is a very preliminary stage of analysis. There aren’t any absolutely right or wrong answers at this stage.

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