5.1 Explain how entities are transformed into tables. 5.3 Why is it necessary to

Question

5.1 Explain how entities are transformed into tables.

5.3 Why is it necessary to apply the normalization process to the tables created accord-

ing to your answer to question 5.1?

5.5 When is denormalization justified?

5.7 Explain how the representation of weak entities differs from the representation of

strong entities.

5.9 List the three types of binary relationships and give an example of each. Do not use

the examples given in this text.

5.11 Show two different ways to represent the 1:1 relationship in your answer to ques-

tion 5.9. Use IE Crow’s Foot E-R diagrams.

5.13 Code SQL statements to create a join that has all data about both tables from your

work for question 5.11.

5.15 Show how to represent the 1:N relationship in your answer to question 5.9. Use an

IE Crow’s Foot E-R diagram.

5.17 For your answer to question 5.15, code an SQL statement that creates a table that

has all data from both tables.

5.19 Give examples of binary 1:N relationships, other than those in this text, for (a) an

optional-to-optional relationship, (b) an optional-to-mandatory relationship, (c) a

mandatory-to-optional relationship, and (d) a mandatory-to-mandatory relation-

ship. Illustrate your answer by using IE Crow’s Foot E-R diagrams.

5.21 Explain the meaning of the term intersection table.

5.23 For your answers to questions 5.20, 5.21, and 5.22, describe a method for obtaining

the children for one of the entities in the original data model, given the primary key

of the table based on the second entity. Also, describe a method for obtaining the

children for the second entity, given the primary key of the table based on the first

entity.

5.25 Why is it not possible to represent N:M relationships with the same strategy used

to represent 1:N relationships?

5.27 Give an example of a 1:N relationship with an ID-dependent weak entity, other

than one shown in this text. Illustrate your answer using an IE Crow’s Foot E-R

diagram.

5.29 Define the three types of recursive binary relationships and give an example of

each, other than the ones shown in this text.

Explanation / Answer

Please find my naswer for first 4 Questions.

Please repost others in separate post.

5.1

Entities can be transformed directly into SQL tables with all attributes mapped one-to-one to table attributes.Tables representing entities that are child of a parent-child relationship must also include as a foreign key,the primary key of the parent entity.A many-to-many relationship is transformed into a table that contains the primary keys of the associated entities as its composite primary key;the components of that key are laso designated as foreign keys in SQL. A ternary or higher level n-ary relationships are transformed into a table that contains the primary keys of the asociated entities;these keys are designated as foreign keys in SQL

5.3 Why is it necessary to apply the normalization process to the tables created according to your answer to question 5.1?
Ans: Because the process is then applied to each relation and additional relations are created.

5.4 What is denormalization?
Ans: Denormalization is the process of intentionally designing a relation that is not normalized; it is done to improve performance or security.

5.5 When is denormalization justified?
Ans: When breaking groups into separate tables will make the designs hard to use

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