Finals Ch 3

The practical significance of taking the logical view of a database is that it serves as a reminder of the simple file concept of data storage. T/F

You can think of a table as a persistent representation of a logical relation. T/F

The order of the rows and columns is important to the DBMS. T/F

Character data can contain any character or symbol intended for mathematical manipulation. T/F

The row's range of permissible values is known as its domain. T/F

Each table in a relational database must have a primary key. T/F

The idea of determination is unique to the database environment. T/F

Only a single attribute, not multiple attributes, can define functional dependence. T/F

If the attribute (B) is functionally dependent on a composite key (A) but not on any subset of that composite key, the attribute (B) is fully functionally dependent on (A). T/F

A null is created when you press the Enter key or the Tab key to move to the next entry without making a prior entry of any kind. T/F

Depending on the sophistication of the application development software, nulls can create problems when functions such as COUNT, AVERAGE, and SUM are used. T/F

RDBMSs enforce integrity rules automatically. T/F

Relational algebra defines the theoretical way of manipulating table contents using relational operators. T/F

The SELECT operator yields a vertical subset of a table. T/F

The DIFFERENCE operator subtracts one table from the other. T/F

In a natural join, the column on which the join was made occurs twice in the new table. T/F

The DIVIDE operation uses one single-column table (e.g., column "a") as the divisor and one two-column table (e.g., columns "a" and "b") as the dividend. T/F

A data dictionary is sometimes described as "the database designer's database" because it records the design decisions about tables and their structures. T/F

The one-to-many (1:M) relationship is easily implemented in the relational model by putting the foreign key of the "1" side in the table of the "many" side as a primary key. T/F

As rare as 1:1 relationships should be, certain conditions absolutely require their use. T/F

__________ logic, used extensively in mathematics, provides a framework in which an assertion (statement of fact) can be verified as either true or false. a. Predicate b. Database c. Relational d. Index

Each table __________ represents an attribute. a. column b. row c. dimension d. value

Date attributes contain calendar dates stored in a special format known as the __________ date format. a. Epoch b. calendar c. Julian d. logical

In the relational model, __________ are important because they are used to ensure that each row in a table is uniquely identifiable. a. relations b. keys c. indexes d. logical structures

A __________ is any key that uniquely identifies each row. a. superkey b. special key c. foreign key d. candidate key

A __________ key can be described as a minimal superkey, a superkey without any unnecessary attributes. a. secondary b. candidate c. primary d. foreign

A __________ is the primary key of one table that has been placed into another table to create a common attribute. a. superkey b. composite primary key c. candidate key d. foreign key

Referential __________ dictates that the foreign key must contain values that match the primary key in the related table, or must contain null. a. integrity b. uniqueness c. model d. attribute

A __________ key is defined as a key that is used strictly for data retrieval purposes. a. lookup b. foreign c. candidate d. secondary

The CUSTOMER table's primary key is CUS_CODE. The CUSTOMER primary key column has no null entries, and all entries are unique. This is an example of __________ integrity. a. entity b. referential c. relational d. null

The __________ constraint can be placed on a column to ensure that every row in the table has a value for that column. a. UNIQUE b. NOT NULL c. VALUE d. EMPTY

To be considered minimally relational, the DBMS must support the key relational operators __________, PROJECT, and JOIN. a. INTERSECT b. UNION c. DIFFERENCE d. SELECT

__________, also known as RESTRICT, yields values for all rows found in a table that satisfy a given condition. a. INTERSECT b. UNION c. DIFFERENCE d. SELECT

__________ returns only the attributes requested, in the order in which they are requested. a. PROJECT b. SELECT c. UNION d. DIFFERENCE

When two or more tables share the same number of columns, and when their corresponding columns share the same or compatible domains, they are said to be __________. a. intersect-compatible b. union-compatible c. difference-compatible d. select-compatible

A(n) __________ join links tables by selecting only the rows with common values in their common attribute(s). a. attribute b. unique c. foreign d. natural

__________ are especially useful when you are trying to determine what values in related tables cause referential integrity problems. a. Inner joins b. Outer joins c. Equijoins d. Theta joins

A(n) __________ only returns matched records from the tables that are being joined. a. outer join b. inner join c. equijoin d. theta join

A __________ contains at least all of the attribute names and characteristics for each table in the system. a. data dictionary b. relational schema c. logical schema d. database

The __________ is actually a system-created database whose tables store the user/designer-created database characteristics and contents. a. database tuple b. systematic database c. unique index d. system catalog

In a database context, the word __________ indicates the use of the same attribute name to label different attributes. a. redundancy b. homonym c. duplicate d. synonym

In a database context, a(n) __________ indicates the use of different names to describe the same attribute. a. entity b. duplicate c. synonym d. homonym

The __________ relationship is the "relational model ideal." a. 1:1 b. 1:M c. M:1 d. M:N

The __________ relationship should be rare in any relational database design. a. 1:1 b. 1:M c. M:1 d. M:N

__________ relationships can be implemented by creating a new entity in 1:M relationships with the original entities. a. 1:N b. M:1 c. M:N d. 1:1

Another name for a composite entity is a(n) __________ entity. a. bridge b. linked c. directive d. associative

A(n) __________ is an orderly arrangement used to logically access rows in a table. a. primary rule b. superkey c. relationship d. index

When you define a table's primary key, the DBMS automatically creates a(n) __________ index on the primary key column(s) you declared. a. key b. composite c. unique d. primary

According to Codd's __________ rule of relational database, "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)." a. nonsubversion b. logical data independence c. comprehensive data sublanguage d. integrity independence

According to Codd's __________ rule of relational database, "If the system supports low-level access to the data, users must not be allowed to bypass the integrity rules of the database." a. nonsubversion b. rule zero c. view updating d. information