Database Systems Design
Implementation And Management 11th
Edition updated (2024/2025) A+ RATED
1. Which relational algebra operators can be applied to a pair of tables that are not
union-compatible? - CORRECT ANSWERSELECT, PROJECT, DIVIDE, PRODUCT,
and JOIN
2. Explain why the data dictionary is sometimes called "the database designer's
database." - CORRECT ANSWERBecause it contains metadata relating to the
datatypes used and sizes as well has the relations in the database.
3. A database user manually notes that "The file contains two hundred records, each
record containing nine fields."
Use appropriate relational database terminology to "translate" that statement. -
CORRECT ANSWERAn entity set contains two hundred tuples with each record
consisting of nine attributes 1. Why are entity integrity and referential integrity important
in a database? - CORRECT ANSWEREntity integrity is important because it means that
a proper search for an existing tuple will always be successful and the failure to find a
match on a row search will always mean that the row for which the search is conducted
does not exist in that table. Referential integrity is important because its existence
ensure that it will be impossible to assign a non existing foreign key value to a table. For
example, the referential integrity enforcement in a SALESREP is assigned to
CUSTOMER relationship means that it will be possible for a customer to not have a
sales rep assigned to him or her but it will be impossible to assign non existing sales rep
to a customer.
4. Explain why the data dictionary is sometimes called "the database designer's
database." - CORRECT ANSWERBecause it contains metadata relating to the
datatypes used and sizes as well has the relations in the database.
5. What is the difference between a database and a table? - CORRECT ANSWERA
table is a logical structure that represents an entity set. It is only one of the components
of a database. The database is a structure that houses one or more tables and
metadata. The metadata includes the data characteristics and the relationships between
the entity sets.
6. What does it mean to say that a database displays both entity integrity and referential
integrity? - CORRECT ANSWEREntity integrity describes a condition in which all tuples
with a table are uniquely identified by their primary key. The unique value requirement
prohibits a null primary key value, because nulls are not unique. Referential integrity
describes a condition i which a foreign key value value has a match i the corresponding
Implementation And Management 11th
Edition updated (2024/2025) A+ RATED
1. Which relational algebra operators can be applied to a pair of tables that are not
union-compatible? - CORRECT ANSWERSELECT, PROJECT, DIVIDE, PRODUCT,
and JOIN
2. Explain why the data dictionary is sometimes called "the database designer's
database." - CORRECT ANSWERBecause it contains metadata relating to the
datatypes used and sizes as well has the relations in the database.
3. A database user manually notes that "The file contains two hundred records, each
record containing nine fields."
Use appropriate relational database terminology to "translate" that statement. -
CORRECT ANSWERAn entity set contains two hundred tuples with each record
consisting of nine attributes 1. Why are entity integrity and referential integrity important
in a database? - CORRECT ANSWEREntity integrity is important because it means that
a proper search for an existing tuple will always be successful and the failure to find a
match on a row search will always mean that the row for which the search is conducted
does not exist in that table. Referential integrity is important because its existence
ensure that it will be impossible to assign a non existing foreign key value to a table. For
example, the referential integrity enforcement in a SALESREP is assigned to
CUSTOMER relationship means that it will be possible for a customer to not have a
sales rep assigned to him or her but it will be impossible to assign non existing sales rep
to a customer.
4. Explain why the data dictionary is sometimes called "the database designer's
database." - CORRECT ANSWERBecause it contains metadata relating to the
datatypes used and sizes as well has the relations in the database.
5. What is the difference between a database and a table? - CORRECT ANSWERA
table is a logical structure that represents an entity set. It is only one of the components
of a database. The database is a structure that houses one or more tables and
metadata. The metadata includes the data characteristics and the relationships between
the entity sets.
6. What does it mean to say that a database displays both entity integrity and referential
integrity? - CORRECT ANSWEREntity integrity describes a condition in which all tuples
with a table are uniquely identified by their primary key. The unique value requirement
prohibits a null primary key value, because nulls are not unique. Referential integrity
describes a condition i which a foreign key value value has a match i the corresponding
