Appendix A: Answers to Review Questions


Chapter 1

1.

Name the most important element of a relational database and its components.

the table is the most important element of a relational database and it consists of rows and columns. a field exists at the intersection of a row and a column.

2.

Which type of table relationship associates more than one record in a given table with more than one record in another table?

a many-to-many relationship associates more than one record in a table with more than one record in another table.

3.

What type of key can be used to enforce referential integrity between two tables in a database?

a foreign key can be used to enforce referential integrity between two tables.

4.

What are some reasons why using a spreadsheet is not a good alternative to using a large-scale database?

some reasons why a spreadsheet is not a good alternative to a large-scale database are that it s difficult to use for multiple users, it does not offer transaction control, the cells in a spreadsheet can contain any type of data, and referential integrity controls between spreadsheets are difficult to implement efficiently.

5.

What are some of the benefits of abstraction in an object-relational database management system?

in an object-relational database management system, new datatypes can be created as aggregates of existing datatypes and other new datatypes, enhancing standards adherence and reusability.

6.

What object-relational feature of Oracle eases the transition between relational and object-relational applications?

object views allow the developer to define an object-oriented structure over an existing relational database table, thus easing the transition between relational and object-relational applications.

7.

What are the three steps in the ERA process for database design?

the three steps in the era (entities, relationships, attributes) design process are to define the entities, then define the relationships between the entities, and then define the attributes of the entities. after one pass through all three steps, one or more iterations may be necessary.

Answers

1.

The table is the most important element of a relational database and it consists of rows and columns. A field exists at the intersection of a row and a column.

2.

A many-to-many relationship associates more than one record in a table with more than one record in another table.

3.

A foreign key can be used to enforce referential integrity between two tables.

4.

Some reasons why a spreadsheet is not a good alternative to a large-scale database are that it’s difficult to use for multiple users, it does not offer transaction control, the cells in a spreadsheet can contain any type of data, and referential integrity controls between spreadsheets are difficult to implement efficiently.

5.

In an object-relational database management system, new datatypes can be created as aggregates of existing datatypes and other new datatypes, enhancing standards adherence and reusability.

6.

Object views allow the developer to define an object-oriented structure over an existing relational database table, thus easing the transition between relational and object-relational applications.

7.

The three steps in the ERA (entities, relationships, attributes) design process are to define the entities, then define the relationships between the entities, and then define the attributes of the entities. After one pass through all three steps, one or more iterations may be necessary.




Oracle9i DBA JumpStart
Oracle9i DBA JumpStart
ISBN: 0782141897
EAN: 2147483647
Year: 2006
Pages: 138
Authors: Bob Bryla

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