Question 1

The ____ relationship should be rare in any relational database design.

Accepted Answer

The 1:1 relationship should be rare in any relational database design as it can lead to duplication of data and inconsistencies. In most cases, the relationship can be normalized by combining the two entities into one. However, there may be some cases where a 1:1 relationship is necessary, such as when splitting a large entity into smaller, more manageable sub-entities.

Question 2

____________________ is the real power behind the relational database,allowing the use of independent tables linked by common attributes.

Accepted Answer

The answer of ____________________ is the real power behind the...

Question 3

In a database context,a(n)____ indicates the use of different names to describe the same attribute.

Accepted Answer

Synonym is the term used when different names are used to describe the same attribute in a database. This can create confusion and inconsistency in data management. It is important to identify and address synonyms to ensure data accuracy and consistency.

Question 4

The ____ relational type is the "relational model ideal."

Accepted Answer

The 1:M (one-to-many) relational type is considered the "relational model ideal" because it efficiently organizes data by linking a single record in one table to multiple records in another, which is a common real-world scenario.

Question 5

In the relational model,____________________ are important because they are used to ensure that each row in a table is uniquely identifiable.

Accepted Answer

The answer of In the relational model,____________________ are important because...

Question 6

In a database context,the word ____ indicates the use of the same attribute name to label different attributes.

Accepted Answer

Homonym refers to the use of the same attribute name for different attributes. Redundancy refers to the unnecessary repetition of data in a database. Duplicate refers to the exact copy of a record or attribute. Synonym refers to different attribute names used to label the same attribute.

Question 7

The following example exhibits ____________________ integrity:
The CUSTOMER table's primary key is CUS_CODE.The CUSTOMER primary key column has no null entries,and all entries are unique.Similarly,the AGENT table's primary key is AGENT_CODE,and this primary key column also is free of null entries.

Accepted Answer

The answer of The following example exhibits ____________________ integrity:
The CUSTOMER...

Question 8

When you define a table's primary key,the DBMS automatically creates a(n)____ index on the primary key column(s)you declared.

Accepted Answer

The DBMS automatically creates a unique index on the primary key column(s) which ensures that the values in the column(s) are unique and cannot be duplicated.

Question 9

A(n)____________________ key can be described as a superkey without unnecessary attributes.

Accepted Answer

The answer of A(n)____________________ key can be described as a...

Question 10

To avoid nulls,some designers use special codes,known as ____________________,to indicate the absence of some value.

Accepted Answer

The answer of To avoid nulls,some designers use special codes,known...

Question 11

PRODUCT yields all possible pairs of rows from two tables-also known as the ____________________ product.

Accepted Answer

The answer of PRODUCT yields all possible pairs of rows...

Question 12

A(n)____ is an ordered arrangement of keys and pointers.

Accepted Answer

An index is an ordered arrangement of keys and pointers that is used to help access and retrieve data from a database more efficiently. It provides a quick way to locate specific rows of data based on the values in one or more columns, which can improve the overall performance of database queries. Tables and relationships are components of a database, but they do not necessarily involve ordered arrangements of keys and pointers. A superkey is a set of attributes that uniquely identifies a tuple (row) in a table, but it is not an ordered arrangement of keys and pointers.

Question 13

If the foreign key contains either matching values or nulls,the table that makes use of that foreign key is said to exhibit ____________________ integrity

Accepted Answer

The answer of If the foreign key contains either matching...

Question 14

The relational operators have the property of ____________________;that is,the use of relational algebra operators on existing relations (tables)produces new relations.

Accepted Answer

The answer of The relational operators have the property of...

Question 15

Codd's Rule of ____ states: Application programs and ad hoc facilities are logically unaffected when changes are made to the table structures that preserve the original table values (changing order of columns or inserting columns).

Accepted Answer

Codd's Rule of Logical Data Independence states that the application programs and ad hoc facilities should not be affected when changes are made to the table structures that preserve the original table values. This includes changing the order of columns or inserting new columns into the table, without changing the meaning or interpretation of the data.

Question 16

The logical view of the relational database is facilitated by the creation of data relationships based on a logical construct known as a(n)____________________.

Accepted Answer

The answer of The logical view of the relational database...

Question 17

Codd's Rule of ____ states: If the system supports low-level access to the data,users must not be allowed to bypass the integrity rules of the database

Accepted Answer

Codd's Rule of Nonsubversion states that if a DBMS has a low-level interface, then users must not be allowed to bypass the integrity rules of the database. This is to ensure the integrity of the data in the database, as allowing users to modify the data directly could lead to inconsistencies and errors. Therefore, A) Nonsubversion is the best choice for this rule.

Question 18

Since it is used to link the tables that originally were related in a M:N relationship,the composite entity structure includes-as foreign keys-at least the ____ keys of the tables that are to be linked.

Accepted Answer

The composite entity structure includes primary keys as foreign keys from the tables that are being linked. This is because the primary keys uniquely identify each record in their respective tables and allow them to be connected in the composite entity.

Question 19

In a relational table,each column has a specific range of values known as the ____________________ domain.

Accepted Answer

The answer of In a relational table,each column has a...

Question 20

Another name for a composite entity is a ____ entity.

Accepted Answer

A composite entity is also known as a bridge entity because it serves as an intermediary to connect two other entities in a database, often in a many-to-many relationship.

Quiz 3: The Relational Database Model