BITM 330

Synonym of tuple

Row

A surrogate key may be appropriate under which of the following circumstances?

The available candidate keys would produce a lot of data duplication when representing relationships The available candidate keys would be prone to typographical errors

Given the functional dependency for the attributes of ENTITY1,X --> (A,B,C), X is a candidate key for the relation ENTITY1 (A,B,C,X).

True

If the condition exists such that knowing the value of attribute X determines the value attribute Y, then attribute Y is functionally dependent on attribute X.

True

In the relational model, many-to-many relationships cannot be directly represented by relations the way 1:1 and 1:N relationships can

True

Surrogate key values have no meaning to the users.

True

IN MS access, the relationship between two tables isnt created until

the CREATE button in the edit relationships dialog box is clicked

In the normalization process if you find that every determinant in a relation is a candidate key, then you have determined that the relation is well formed

true

Null values can cause problems because they are ambiguous

true

Is the table Employee(Employee_ID, First_Name, Last_Name, Phone, Position_ID, Position_Description) in A) 1NF B) 2 NF C) 3 NF D) 4NF

2NF

In the normalization process, if you find a candidate key that is not a primary key, then you have determined that the relation needs to be broken into two or more other relations

False

In the normalization process, it is not necessary to identify all the functional dependencies in a relation

False

In the relational model, each row of a table contains data that represents an attribute of the entity

False

Normalization is the process of removing all functional dependencies from a relation

False

Since surrogate keys are used to uniquely identify rows, their values are normally displayed prominently on all forms and reports for the users to see

False

The use of surrogate keys usually complicates application programming since most DBMS products require the application program to generate surrogate key values.

False

1st step of the normalization process is to

Identify all the candidate keys of a relation

1st Normal Form (1NF)

each row/column intersection contains one and only one value, not a set of values; all attributes are dependent on the primary key

A key must be unique

false

Candidate keys may or may not be unique

false

In microsoft access, a relationship is created by dragging a foreign key column and dropping it on top of the corresponding primary key

false

In microsoft access, foreign keys are designated by using the foreign key button in the toolbar

false

Microsoft acces forms can only contain data from one table

false

When the primary key of one relation is placed into a second relation it is called a

foreign key

A rule that requires that the values in a foreign key must have a matching value in the primary key to which the foreign key corresponds is called

referential integrity constraint

A primary key is

required to be unique used to represent rows in a relationship a candidate key used to identify unique rows

A candidate key is

required to be unique used to represent rows in relationships a candidate to be the primary key

If every determinant in a relation is a candidate key thnen

the relation is well formed

Determinant

Any attribute in a specific row whose value directly determines other values in that row.

A stable that meets the requirements of a relation is said to be in whcih normal form? A) Relational normal form(RNF) B) First normal form C)Second normal form D)Boyce-Codd normal form E) Domain/key normal form

B

Which of the following is true about a relation A)The order of the columns in a relation must go from largest to smallest B) All entries in any column must be of the same kind C) A relation may have duplicate column names D) a relation may have duplicate rows E) a relation may have multiple names

B

In the normalization process, it is not necessary to A) identify all the candidate keys of a relation B)Identify all the foreign keys of a relation C) identify all the functional dependencies of a relation D) identify all the determinants of a relation E) determine if every determinant is a candidate key

B) Identify all the foreign keys of a relation

Any table that meets the definition of a relation is said to be in second normal form

False

When used to represent a relationship, the primary key must have the same name as the corresponding foreign key.

False

In SQL server the starting value of a surrogate key is called the

Identity seed

One to many relationship (1:M)

One thing can have many results ex. One customer can have many orders

Orders(Order_Id, BarCode, Quantity, Item_decription, Date_Purchased, SalesPerson_ID, SalesPerson_First, SalesPerson_Last)

Orders(Order_Id, Date_Purchased, SalesPerson_ID, SalesPerson_First, SalesPerson_Last) Items(BarCode, Item_decription) OrderLine (Order_Id, BarCode, Quantity) 2nf but not 3nf Orders(Order_Id, Date_Purchased, SalesPerson_ID) Items(BarCode, Item_decription) OrderLine (Order_Id, BarCode, Quantity) Sales_Persons(SalesPerson_ID, SalesPerson_First, SalesPerson_Last)

Synonym of relation

Table

To be considered a composite key, a key must contain at least two attributes

True

To create a well-formed relation through normalization, every determinant must be a candidate key.

True

one-to-one relationship (1:1)

a relationship between two entities in which an instance of one entity can be related to only one instance of a related entity ex. Each student has one ID

Every cell in a relation can hold only a single value

true

In microsoft access, relationships between tables are created in the relationships window

true

The first step of the normalization process is to identify all the candidate keys of a relation

true

The primary key is used both to identify unique rows in a relation and to represent rows in relationships

true

to represent a relationship in the relational model the primary key of one relation is placed into a second relation

true

Which split of the table from the question 5: Employee(Employee_ID, First_Name, Last_Name, Phone, Position_ID, Position_Description) is correct A)Employee(Employee_ID, First_Name, Last_Name, Phone, Position_ID) Position(Position_ID,Position_Description) B)Employee(Employee_ID, First_Name, Last_Name, Phone) Position(Position_ID,Position_Description) c)Employee(Employee_ID, First_Name, Last_Name, Phone) Position(Position_ID,Position_Description, Employee_ID)

A

3rd Normal Form (3NF)

A relation that is in 1NF and 2NF, and in which no non-primary key attribute is transitively dependent on the primary key. That is, all non-key elements are fully dependent on the primary key Cant have: column x depends on column y which depends upon the primary key z

2nd Normal Form (2NF)

A relation that is in 1NF and every non-primary key attribute is fully dependent on the primary key. That is, all the incomplete dependencies have been removed Partial Dependency Table: book_author (taken by book_ID and author_ID combined to make primary key) 1. book_ID 2. author_ID 3. author_position 4. ISBN ISBN is a partial dependency because it only references book_ID. Does not have anything to do with author_ID

Candidate Key

An attribute, or combination of attributes, that uniquely identifies a row in a relation.

In microsoft access referential integrity constraints are created

By checking the enforce referential integrity check box in the edit relationships dialog box

In microsoft access a relationship between two tables is created

By dragging the primary key column of one table onto the foreign key column of the other table in the relationships window

Which of the following is not true about a relation? A) a relation is a two dimensional table B) the cells of a relation must hold a single value C) A relation may have duplicate column names D) A relation may not have duplicate rows E) the order of the rows of a relation is insignificant

C

durring the normalization process, the remedy for a relation that is not well formed is to A)create a surrogate key B) create a functional dependency C) break it into two or more relations that are well formed D) Combine it with another relation that is well formed E) Convert it into a list

C

The first step in trnasforming an extended E-R model into a relational database design is to __________ A) Create a table for each relationship B) Evaluate the entities against the nromalization criteria C) Create a table for each entity D) Remove any recursive relationships E) Document Referential integrity constraints

C) Create a table for each entity

Refer t the database Premier Products with tables: Orders, Order_line, parts. Assume that table parts has attributes: Partnumber, Description, on_hand, Min_on_Hand and price. To create a price list for a super sales event with 10% discount you will reate a _______ and in the new field Sales_Price Put: _____ A) Table, Sales_Price:price *.10 B) Query, Sales_Price:price*0.10 C) Query, Sales_Price:price*0.90 D) Table, sales_price:price*0.90

C) Query, Sales_Price:price*0.90

Fourth Formal Form (4NF)

Cant have something with many possibilities Employee, skill_proficiency, Language_profficciency Employee 101 can do archery, badminton, darts. Employee 101 can speak chinese, german, french

A key that contains more than one attribute is called a(n):

Composite key

Find the PK for the table Employee(Employee_ID, First_Name, Last_Name, Phone, Position_ID, Position_Description)

Employee_ID

One important relational design principle is that

Every determinent must be a candidate key

In the normalization process, if you find a candidate key that is not a determinant then you should A) place the columns of the functional dependency in a new relation B) Make the determinant of the functional dependency the primary key of the new relation C) leave a copy of the determinant as a foreign key in the original relation D)all of the above E) none of the above

D) all of the above

Which of the following is not true about null values A)A null value can mean that the value is unknown B) the null value is ambiguous C) the null value can mean that the value is known to be blank D) a null value can mean that no value for the field is appropriate E) Null values cannot be avoided

E

Which of the following is true about a key A) It may be unique B) it may be non unique C) it may identify more that one row D) Both a and B E) All of the above

E

In the normalization process, if you find a candidate key that is not a primary key, then you should A) place the columns of the functional dependency in a new relation B) make the determinant of the functional dependency the primary key of the new relation C) leave a copy of the determinant as a foreign key in the original relation D) all of the above E) none of the above

E none of the above

A database may be used to help people: A) Track which student is assigned to a particular advisor B) Check on the estimated arrival time of an incoming flight at an airport C) Check on the eliminated arrival time of anincoming flight at an airport D) Look at their checking account balance over the internet E) All of the above

E) All of the above

Refer to the database Premier products with tables: Orders, Order_line, Parts. The reason for having a table parts may be: A) To list prices B) To present number of each item on hand C) To present current customers D) All of the Above E) Only A) and B)

E) Only A) and B)

Infinity symbol

The symbol that indicates the "many" side of a one-to-many relationship.

Which of the following is not true of surrogate keys A) meaningful to the users b) they are numeric C) usually generated by the dbms D) they are unique E) they are usually hidden on forms and reports

They are meaningful to the users

Every relation is a table, but not every table is a relation.

True

In microsoft access, relationships between tables are created

in the relationships window

many-to-many relationship (M:N)

is between two entities in which an instance of one entity is related to many instances of another and one instance of the other can be related to many instances of the first entity ex: Many students to many classes and many classes can have many students