CSDP Step 2: Conceptual Schema Design Procedure

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Questions and Answers

What is the process of generating value type names from unit-based reference modes?

Replacing the reference by 'Type'

Replacing the colon by 'Value' (correct)

Replacing the unit by 'Fact'

Replacing the mode by 'Unit'

What is the purpose of populating each fact type on the diagram with some of the original fact instances?

To identify the object types

To create a knowledge base diagram

To draw the fact types

To apply a population check (correct)

What is a table for displaying instances of a fact type called in ORM?

Knowledge base diagram

Fact table (correct)

Population check table

Schema diagram

What is a diagram that includes both a schema and a sample database called?

Knowledge base diagram Signup and view all the answers

How are object types identified in a fact table when they are simply identified?

In a separate column Signup and view all the answers

What is the purpose of Figure 3.11 in the given content?

To show the knowledge base diagram with the original data Signup and view all the answers

What is depicted as a solid line in the conceptual schema diagram?

A particular fact or relationship between a person and a car Signup and view all the answers

How are individual objects portrayed on an instance diagram?

By icons or text Signup and view all the answers

What is shown as a broken line in the conceptual schema diagram?

A particular reference between a value and an entity Signup and view all the answers

How are roles (relationship parts) played by objects shown on a conceptual schema diagram?

As boxes Signup and view all the answers

What is the shape of a value type on a conceptual schema diagram?

A named, broken, soft rectangle Signup and view all the answers

What is an entity type depicted as on a conceptual schema diagram?

A named, solid, soft rectangle Signup and view all the answers

How are individual objects represented on a conceptual schema diagram?

Omitted Signup and view all the answers

What can optionally be given to roles on a conceptual schema diagram?

A name Signup and view all the answers

What is the primary purpose of drawing a conceptual schema diagram in CSDP STEP 2?

To illustrate the relevant object types, predicates, and reference schemes Signup and view all the answers

What is the purpose of checking the conceptual schema diagram with a sample population?

To validate the diagram's accuracy Signup and view all the answers

What does the instance diagram illustrate?

Particular instances of objects and relationships Signup and view all the answers

What is the purpose of using 'regNr' as an abbreviation?

To abbreviate 'registration number' Signup and view all the answers

What is the next step in the conceptual schema design procedure after translating information examples into elementary facts?

Drawing a conceptual schema diagram Signup and view all the answers

What is shown in the conceptual schema diagram?

All the fact types Signup and view all the answers

What is the purpose of CSDP STEP 2?

To draw a conceptual schema diagram and populate it with sample facts Signup and view all the answers

What is represented in the elementary facts using 'regNr'?

The car's registration number Signup and view all the answers

What is the purpose of a report like Table 3.8?

To show the preference of nonsmokers Signup and view all the answers

What is the difference between unary fact types and other fact types?

Unary fact types have only one role Signup and view all the answers

What is an example of a unary fact type in Table 3.8?

Person (firstname) ‘Lee’ is a nonsmoker Signup and view all the answers

What is the main difference between Table 3.8 and the licens plate table?

One is for cars and the other is for people Signup and view all the answers

What is the purpose of CSDP step 2?

To draw the fact types and apply a population check Signup and view all the answers

What is the meaning of 'Person (firstname) ‘Amie’ smokes'?

Amie is a smoker Signup and view all the answers

What does the licens plate table show?

The licens plates of people Signup and view all the answers

What is the difference between the tables in this content?

One is for fact types and the other is for licens plates Signup and view all the answers

What is shown by separating the role boxes in Figure 3.12?

The roles belong to different fact types Signup and view all the answers

What is the result of transforming the two unaries into a single binary in Figure 3.13?

The introduction of SmokingStatus as another entity type Signup and view all the answers

What is the characteristic of a homogeneous fact type?

Each role is played by the same object type Signup and view all the answers

What is the term used to describe the binary case of a homogeneous fact type?

Ring fact type Signup and view all the answers

What is the characteristic of a ring fact type?

The path from the object type through the predicate forms a ring Signup and view all the answers

What is shown in Figure 3.13?

A binary fact type with SmokingStatus as another entity type Signup and view all the answers

What is the entity type introduced in Figure 3.13?

SmokingStatus Signup and view all the answers

How can the first row of Table 3.8 be rephrased?

Person ‘Pat’ has SmokingStatus(.code) ‘S’ Signup and view all the answers

Study Notes

CSDP Step 2: Draw Fact Types and Populate

CSDP Step 2 involves drawing a conceptual schema diagram that shows all the fact types, which illustrates the relevant object types, predicates, and reference schemes.
The diagram is then checked with a sample population.
Conceptual schema diagrams depict an entity type as a named, solid, soft rectangle (rectangle with rounded corners).
A value type is shown as a named, broken, soft rectangle.
Object type names are written inside the rectangle.

Instance Diagrams

Instance diagrams illustrate particular instances of objects and relationships.
Cartoon drawings are used to denote the actual people and cars.
Values are shown as character strings.
A particular fact or relationship between a person and a car is shown as a solid line.
A particular reference between a value and an entity is shown as a broken line.

Fact Types and Population

As a check, each fact type on the diagram is populated with some of the original fact instances.
A fact table is added for each fact type, and the values are entered in the relevant columns of the table.
A diagram that includes both a schema and a sample database is called a knowledge base diagram.

Examples

The example of Table 3.6 shows three elementary facts: • The Person named ‘Adams B’ drives the Car with regNr ‘235PZN’. • The Person named ‘Jones E’ drives the Car with regNr ‘235PZN’. • The Person named ‘Jones E’ drives the Car with regNr ‘108AAQ’.
Figure 3.8 shows an instance diagram for this example.
Figure 3.9 shows a conceptual schema diagram for the same example, with inverse readings for the two fact types.

Roles and Value Types

On a conceptual schema diagram, the roles (relationship parts) played by objects are shown explicitly as boxes.
Optionally, roles may be given a name, in which case the role name is displayed in square brackets next to the role box.
Value type names are generated from unit-based reference modes by replacing the colon by “Value” (in English).

Unary and Binary Fact Types

Table 3.8 shows an example of unary fact types, where each fact is an instance of a different unary fact type.
The knowledge base diagram is shown in Figure 3.12, where the two roles belong to different fact types.
The two unaries can be transformed into a single binary by introducing another entity type, such as SmokingStatus.
The binary version is shown in Figure 3.13.

Ring Fact Type

A ring fact type has one entity type, where each role in a fact type is played by the same object type.
The binary case of this is called a ring fact type, since the path from the object type through the predicate loops back to the same object type, forming a ring.
Figure 3.14 shows an example of a ring fact type with a sample population.

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Description

This quiz covers the second step in the Conceptual Schema Design Procedure (CSDP), which involves drawing fact types and populating them with sample facts. It's an essential step in database design.