Question

Please do not delete the questions.

1. What is the purpose of a database?

2. What is the reason to use a database over a spreadsheet?

3. Based on the previous answers (#1 & #2), there is a simple rule of thumb.

A spread sheet is used when there is _________________________.

A database is used when there are _________________________.

4. Please answer followings.

a) A group of 8 bits is called a ____________ (from Chapter 4).

b) The answers of a) are grouped into _Columns_ or _Fields___ (answers provided for this question).

c) The answers of b) are grouped into _____________ or ______________.

d) The answers of c) are grouped into _____________ or ______________.

5. Database is not just collection of tables. Then, what is a database?

6. The most commonly used database is called a relational database (there are different types of databases such as hierarchical databases and object-oriented databases; however, we will not cover those databases in this class). The database that you are studying in this class is also a relational database. Why do we call this database a relational database?

7. What is a primary key?

8. The following table shows a part of a database. What is a primary key in the following table and why? Your answer must also have an explanation on why the other column or columns cannot be a primary key, if there is no explanation, you will not receive any points.

StudentID	FirstName	LastName	Major
287530023	Emily	Jackson	Marketing
287529983	Sean	King	Accounting
287422421	Abigail	Smith	Management

9. What is a foreign key? (Note: a foreign key is used to link tables together)

10. What is metadata?

11. What is a DBMS?

12. What is the language that is used to process a database (Note: international standard language)? Please provide its full name.

13. Please fill in the blank.

Types	Product	Vendor
Enterprise DBMS	DB2
		Open source

14. List the DBMS administrative functions.

15. What is a database application?

16. What is a data model?

17. Which tool is the most commonly used for constructing a data model?

18. What is an entity?

19. What problem do you see with the following entity? (hint: please read the entity part carefully)

   Customers

Mina Park: This is a simple explanation regarding relationships (the question will start from #28), so please read this part carefully. There are three different types of relationships (in maximum cardinality for the relationship, do not worry about minimum cardinality for this assignment; I want you to read and know about minimum cardinality though); 1:1 (one-to-one), 1:N (one-to-many), and N:M (many-to-many). The example of a 1:1 relationship is students and parking decals at Southern Connecticut State University. One student has only one parking decal, and one parking decal belongs to only one student. This is true under the assumption that SCSU issues one parking decal to one student, a university that allows more than one parking decal per student may exist. Again, it is really important that we specify the assumption when you come up with your diagram. This is also very important in cases in real industry, since every company or organization has different rules/processes.

No single diagram fits all situations. Therefore, please make sure that you explain your assumptions with your diagram answers.

For questions 24 through 26, please draw E-R diagrams and explain the relationships (with assumptions explained). You can just draw maximum cardinality (do not worry about minimum cardinality of the relationship for this assignment; I want you to read and know about minimum cardinality though). You can use any tools to draw the E-R diagram (I used PowerPoint for #20, but you can use any tool). Please come up with your own examples. If you use the same examples from the textbook, it will just show me how pretty you draw the diagram rather than how well you understand the concepts and how easily you can apply your understanding to the diagram. Thank you.

24. Please draw a 1:1 E-R diagram and explain the relationship (should have two entities).

25. Please draw a 1:N E-R diagram and explain the relationship (should have two entities, with crow’s foot notation).

26. Please draw a N:M E-R diagram and explain the relationship (should have two entities, with crow’s foot notation).

27. What is normalization?

28. Please normalize the following table [example from “Microsoft Office 2010: Advanced (Shelly Cashman Series)]. If you properly normalize, you will have two tables as answers.

Client Num	Client Name	Street	City	State	Current Due	Recruiter Number	Last Name	First Name	Commission
AC34	Alys Clinic	134 Central	Berridge	CO	$17,500.00	21	Kerry	Alyssa	$17,600.00
BH72	Berls Hospital	415 Main	Berls	CO	$0.00	24	Reeves	Camden	$19,900.00
BL12	Benton Labs	12 Mountain	Denton	CO	$38,225.00	24	Reeves	Camden	$19,900.00
EA45	ENT Assoc.	867 Ridge	Fort Stewart	CO	$12,750.00	27	Fernandez	Jaime	$9,450.00
FD89	Ferb Dentistry	34 Crestview	Berridge	CO	$12,500.00	21	Kerry	Alyssa	$17,600.00
FH22	Family Health	123 Second	Tarleton	CO	$0.00	24	Reeves	Camden	$19,900.00

20. What are attributes?

21. What is an identifier?

22. What is an E-R diagram?

23. When is crow’s feet used in an E-R diagram?

Answer 1

1.The purpose of a database is to systematically arrange,store and retrieve data.

2.A database systematically stores data and it is easy to retrieve them. It maintains consistency,integrity and security of data over spreadsheet.

3.A database is used for long term storage whereas a spreadsheet is usually used for short term and sized data.

4.a)byte c)relations or tables d)database or spreadsheet

5.A database is a collection of related data.It arranges,stores and retrieves data systematically.

6.A relational database is a collection of relations(tables). In such a database, all relations are connected to each other and has some relation between all the entities.

7.A primary key is an attribute or a set of attributes that is used to uniquely identify a tuple in a relation.It is like an ID and primary key for each row must be different in a relation.

8.The attribute StudentID is the primary key for this relation because every student has a unique id. But the FirstName , LastName and Major need not be unique for every tuple.

9.A Foreign key is an attribute or a set of attributes which is the primary key in some other relation. It is used to link two tables.

10.Metadata is the data about data. It defines the details about the database,that is the schema of the database.

11.Database Management System(DBMS) is a software used to define,store,manipulate,retrieve and maintain data in a database.

12.Structured Query Language(SQL)

13.Product              Vendor

     DB2                  IBM

     MySQL                       opensource

14.The DBMS administration includes the overall management of the resources.

15.A computer program that interacts with a computerized database for storing and retrieving data is called a database application.for example,SAP,Facebook.

16.Data model is a logical representation of DBMS.It represents how data is stored and retrieved in a database and how the data is related to each other.

17.The most commonly used tool for constructing a data model is an ER Diagram.

18.An entity is similar to a real world entity that has an actual existence and has some associated properties called its attributes.for eg,Student,Employee,school etc.

20.Attributes are the properties that describes an entity.for eg,Name,Age,Class,Grade etc are the attributes for an entity Student.

21.An identifier is something used to identify a database,relation or its attributes.It is the name given to any of it.

22.An E-R diagram is a tool for constructing the conceptual model of a database.It defines real world entities with their attributes and the relations between each entity.

23.Crow's foot notations are used at the end of lines to represent the cardinality of that relation.

24.

   DEPARTMENT and HOD are two entities. Every DEPARTMENT is managed by one and only one HOD and every HOD has one DEPARTMENT under him.So,it is a 1:1 relation.

25.

          

           Every DEPARTMENT has several employees and every EMPLOYEE works for one and only one department.

          so it is a 1:N relation.

26.

            

Many Employees can work on many projects.So it is a M:N relation.

27.Normalization is a way of organizing data in a database.It divides a table into several small tables so it is efficient.