Practice 1 1: Instance or Entity

Transcription

1 Practice 1 1: Instance or Entity Practice 1 1: Instance or Entity Goal (See Page 47) The goal of this practice is to learn to make a distinction between an entity, an attribute, and an instance of an entity. List which of the following concepts you think is an Entity, Attribute, or Instance. If you mark one as an entity, then give an example instance. If you mark one as an attribute or instance, give an entity. For the last three rows, find a concept that fits. Practice: Instance or Entity? Concept PRESIDENT ELLA FITZGERALD DOG ANIMAL HEIGHT E/A/I? Example Instance or Entity E CAR A CAR I CAR

2 Lesson 1: Introduction to Entities, Attributes, and Relationships Practice 1 2: Guest Goal (See Page 47) The goal of this practice is to recognize attributes for an entity. Scenario On the left side of the illustration are three entities that play a role in a hotel environment: GUEST, HOTEL, and ROOM. On the right is a choice of attributes. Draw a line between the attribute and the entity or entities it describes. Practice: Guest GUEST HOTEL ROOM Address Arrival Date Family Name Room Number Floor Number Number of Beds Number of Parking Lots Price TV set available? Data Modeling and Relational Database Design

3 Practice 1 3: Reading Practice 1 3: Reading Goal (See Page 49) The goal of this practice is to read a relationship. Which text corresponds to the diagram? Practice: Reading EMPLOYEE assigned to responsible for DEPARTMENT A Each EMPLOYEE may be assigned to one or more DEPARTMENTS Each DEPARTMENT must be responsible for one or more EMPLOYEES B Each EMPLOYEE must be assigned to one or more DEPARTMENTS Each DEPARTMENT may be responsible for one or more EMPLOYEES C Each EMPLOYEE must be assigned to exactly one DEPARTMENT Each DEPARTMENT may be responsible for exactly one EMPLOYEE

4 Lesson 1: Introduction to Entities, Attributes, and Relationships Practice 1 4: Read and Comment (See Page 49) 1 Read each of the relationships in the model presented here. 2 Next, comment on the relationship you just read. Use your knowledge of people and towns. Practice: Read and Comment PERSON born in birthplace of TOWN living in home town of visitor of visited by mayor of with mayor Data Modeling and Relational Database Design

5 Practice 1 5: Hotel Practice 1 5: Hotel (See Page 51) 1 Comment on the relationships of the model presented here. Practice: Hotel HOTEL * Address the lodging for ROOM * Room Number with host of in in STAY * Arrival Date of with guest in PERSON * Name Make up two more possible relationships between PERSON and HOTEL that might be of some use for the hotel business. 1-33

6 Lesson 1: Introduction to Entities, Attributes, and Relationships Practice 1 6: Recipe Goal (See Page 51) The goal of this practice is to discover the various types of information that are present in a given source of information. Scenario You work as an analyst for a publishing company that wants to make recipes available on the Web. It wants the public to be able to search for recipes in a very easy way. Your ideas about easy ways are highly esteemed. 1 Analyze the example page from Ralph s famous Raving Recipes book and list as many different types of information that you can find that seem important. Ralph s Raving Recipes Soups vegetarian 15 min easy preparation Açorda alentejana bread soup from Portugal for 4 persons: 1 onion 4 cloves of garlic 1 red pepper 1 liter of vegetable broth 4 tablespoons of olive oil 4 fresh eggs 1 handful of parsley or coriander salt, pepper 9-12 slices of (old) bread Cut the onion into small pieces and fry together with the garlic. Wash the red pepper, cut it in half, remove the seeds and fry it for at least 15 page Group the various types of information into entities and attributes. 3 Name the relationships you discover and draw a diagram Data Modeling and Relational Database Design