Monica Harrison				Databases					12-8-03

Ch. 1

1. What are the advantages of computerized databases over manual systems of storing data?

Computerized databases provide organized data storage, reducced data redundancy, data sharing, data access, data security, and data management, none of which does manual storage provide to the same degree.

2. What are the components of a database?

A database consists of records, tables, rows, and columns.

3.List the differences between a DBMS and an RDBMS.

 An RDBMS is based on relations between the data, while a DBMS is based on the data itself. An RDBMS is easier to implement and provides a higher degree of structural and functional complexity. An RDBMS identifies each table in the database as a relation and each column as an attribute, while a DBMS does not use relations.

4. What is the use of the primary key in a table? Can a table have more than one primary key?

A primary key uniquely identifies a tuple of a table beacuse the value of the primary key must be unique for each tuple. Because of this it enables faster searches and relationships between tables. There can only be one primary key per table.

5. Which of the following data storage mechanismis is suited for a large organization that has several departsments, such as Production, Finance, and Sales? Provide reasons to support your choice.

c. An RDBMS. It stores data in an easily accessable manner with relations. It's easy to search and to sort.

6. Data inconsistency results from: d. Data manipulation.

7. Research the Web and write a short note on PL/SQL.

Short for Procedural Language/Structured Query Language. Oracle's extension to the industry standard SQL. It is typically used to wirte data-centric programs to manipulate data in an Oracle database. 

Thanks to webopedia.com for the info.

Ch 2

1. What are the advantages of the relational data model over other data models? flexibility - "The relational aspects of the database provide a great deal of flexibility and allow for a wide number of operations to manipulate the data and gather meaningful reports and information." p. 2.6

2. 

3. Why are data modeling techniques used in database development?

Data models make it easier to design the different types of databases that allow for effective data storage and management.

4. What is the difference between relational and object-oriented databases?

An object-oriented database uses ideas from object oriented programing. A relational database contains information about relations between data in tables.

5. How is the E-R models useful in building a database?

It helps the designer see the database from the user's perpective and understand how best to build the database on multiple levels.

6. Differentiate between various types of entities.

Independent entities exist independently and have properties specific to them. Dependent entities depend on other entities.

7. Where is the NULL value attribute used?

NULL is used when an attribute value for a particular entitiy is not applicable.

8.