Deck 10: Databases

Question 1

A foreign key allows Visual Basic to join together two tables from a relational database in a meaningful way.

Answer 1

True

Question 2

What is a primary key?

A) A field that uniquely identifies each record.
B) The first field in every record..
C) The largest field in every record..
D) The first field specified when a table is created.

Answer 2

A

Question 3

A rectangular array of data is called a

A) field.
B) record.
C) table.
D) database management system.

Answer 3

C

Question 4

Once a field has been specified as a primary key, Visual Basic will not allow that field to contain an empty entry for any record.

Question 5

Each entry of a field of a table must contain some information.

Question 6

The error message You cannot add or change a record because a related record is required in table 'Countries'. will be generated by attempting which of the following with the Megacities database?

A) A user tries to enter a record in the table Countries that doesn't contain data in the primary key.
B) A user tries to add a record to a table that is related to the Countries table, and that record contains a foreign key value that does not correspond to a primary key value in the Countries table.
C) A user tries to enter a record to the table Countries with the same primary key as another record.
D) The user tries to request a joined table using LINQ.

Question 7

Which of the following is used to uniquely identify records in a table?

A) a Rule of Referential Integrity
B) a foreign key
C) a primary key
D) a relational database

Question 8

Which one of the following statements is true about primary keys?

A) A column of names is usually a good choice for use as a primary key.
B) Only a single record can be used as a primary key.
C) Social Security numbers are never used as a primary key.
D) A primary key is used to uniquely identify records in a table.

Question 9

Which of the following allows the linking together of two or more interdependent tables in a meaningful way?

A) ANSI
B) foreign keys
C) duplicate entries in a single field
D) null values

Question 10

Which of the following terms is defined as two or more interdependent tables?

A) Rule of Referential Integrity
B) join
C) joined database
D) relational database

Question 11

The error message Index or primary key cannot contain a Null Value. will be generated by attempting which of the following?

A) A user tries to enter a record in the table Countries that doesn't contain data in the primary key.
B) A user tries to add a record to a table that is related to the Countries table, and that record contains a foreign key value that does NOT correspond to a primary key value in the Countries table.
C) A user tries to enter a record in the table Countries with the same primary key as another record.
D) A user tries to request a joined table using LINQ.

Question 12

The error message The changes you requested to the table were not successful because they would create duplicate values in the index, primary key, or relationship. Change the data in the field or fields that contain duplicate data, remove the index, or redefine the index to permit duplicate entries and try again. will be generated by attempting which of the following?

A) A user tries to enter a record in the table Countries that doesn't contain data in the primary key.
B) A user tries to add a record to a table that is related to the Countries table, and that record contains a foreign key value that does NOT correspond to a primary key value in the Countries table.
C) A user tries to enter a record in the table Countries with the same primary key as another record.
D) A user tries to request a joined table using the SQL language.

Question 13

DataBase Explorer can be used to browse through all parts of a connected database.

Question 14

Which one of the following statements is NOT true about tables?

A) Each column of a table represents a field.
B) Each row of a table represents a record.
C) Each record in a table contains unrelated collections of fields.
D) A table is a rectangular array of data.

Question 15

Which of the following is a collection of one or more (usually related) rectangular arrays of data?

A) a table
B) a field
C) a record
D) a database

Question 16

Which of the following is used to insure that each value for a foreign key also appears as a value for the primary key in any related table?

A) the Rule of Referential Integrity
B) the Join statement
C) SQL
D) a relational database

Question 17

Each row in a table is also called a(n)

A) record.
B) array.
C) field.
D) selection.

Question 18

The requirement that no record may have a null primary key and that entries for primary keys be unique is called the

A) Rule of Referential Integrity.
B) Rule of Primary Keys.
C) Rule of Entity Integrity.
D) Rule of Null Values.

Question 19

The management of databases is one of the major uses of computers today.

Question 20

The Rule of Referential Integrity insists that each value in the foreign key must also appear in the primary key of the other table.

Question 21

When a navigation toolbar is used with a table from a database, the Find method of the BindingSource control returns the value -1 if it cannot locate the sought after record.

Question 22

LINQ can be used in Visual Basic to sort records.

Question 23

What control causes a binding navigator toolbar to appear anchored to the top of the form?

A) BindingNavigator
B) NavigatorToolbar
C) Navigator
D) BindingToolbar

Question 24

When a navigation toolbar is used with a table from a database, the first record of the table has index .

A) 0
B) 1
C) First
D) -1

Question 25

Which of the following is NOT a button on the navigation toolbar?

A) Current position
B) Add new
C) Find
D) Delete

Question 26

When a navigation toolbar is used with a table from a database, the Find method of the BindingSource control returns the position of a record.

Question 27

The Move next button of a navigator toolbar is never disabled.

Question 28

When a navigation toolbar is used with a table from a database, the statement BindingSource1.Position = n makes the record of index n the current record.

Question 29

When a navigation toolbar is used with a table from a database, the first record of the table has position .

A) 0
B) 1
C) First
D) -1

Question 30

Data normalization is the process of avoiding redundancy by splitting a table into two or more related tables.

Question 31

When a navigation toolbar is used with a table from a database, the value of BindingSource1.Position is the position of the current record.

Question 32

Dragging a field name form the Data Sources window to the form automatically generates a label and a text box bound to the field.

Question 33

A LINQ clause beginning with Join and ending with a phrase of the form On foreign key of tblA Equals primary key of tblB causes two tables to be joined.

Question 34

For purposes of readability it is often a good idea to have fields whose values can be computed from other fields.