WGU C170 DATA MANAGEMENT
APPLICATIONS LATEST VERSION
UPDATED AND REVISED IN 2024-2025
What is a table? - - ANSWER ->-A table is a persistent
representation of a logical relation that is a relation whose
contents can be saved for permanent use.
What are the characteristics of a relational table? - - ANSWER -
>-The characteristics of a relational table are that a table is
perceived as a two-dimensional structure composed of rows
and columns, each row (tuple) represents a single entity
occurrence within the set, each column represents an attribute,
each column has a distinct name, each intersection of a row
and column represents a single data value, all values in a
column must be of the same data format, the order of the rows
and columns don't matter to the DBMS, and
each table must have an attribute (or combination of
attributes) that uniquely identifies each row (tuple).
What is a tuple? - - ANSWER ->-A tuple is a row that represents
a single entity occurrence within a set.
What are records? - - ANSWER ->-A record is the same as a
tuple (row).
,What is a field? - - ANSWER ->-A field is a column.
What is a key? - - ANSWER ->-A key consists of one or more
attributes that determine other attributes. For example, a
social security number identifies all of the other attributes
related to that person.
What is determination? - - ANSWER ->-Determination is the
state in which knowing the value of one attribute allows you to
determine the value of another attribute. For example, if you
know a key, you can find other information.
What is functional dependence? - - ANSWER ->-Functional
dependence is when knowing the value of one or more
attributes lets you know the value of the other attributes. For
example, knowing the first name and the social security
number would let you find the person's last name.
What is full functional dependence? - - ANSWER ->-Full
functional dependence is when knowing the value of one or
more attributes lets you know the value of other attributes and
the value of the known attributes are NEEDED to find the other
attributes. For example, a social security number lets you find
the first and last name of someone. This is full functional
dependence. If it was a social security number and a first name
this would just be functional dependence because the first
name is not required to look up the last name. All you need is
the SSN.
,What is a determinant? - - ANSWER ->-A determinant is an
attribute whose value determines the value of other attributes.
For example, a social security number could be the determinant
for your last name.
What is a dependent? - - ANSWER ->-A dependent is an
attribute whose value is determined by another attribute. For
example, you last name could be a dependent of your social
security number.
What is a composite key? - - ANSWER ->-A composite key is a
key that is composed of one or more attribute. For example,
the key of your last name and you social security number could
be used to determine your first name. This would be a
composite key because you are using your last name and your
SSN in the key.
What is a superkey? - - ANSWER ->-A superkey is a key that can
uniquely identify any row in a table. Some examples of this
would be your social security number identifying a row
corresponding to your information, but a superkey isn't limited
to full functional dependence. Your SSN and your last name
used as a key would still be a superkey.
What is a candidate key? - - ANSWER ->-A candidate key is a
minimal super key. This is to say it has no extra attributes. If
you only need a social security number to identify the row
related to a person than the candidate key is the SSN. A key
, consisting of an SSN and the last name in this case would not be
a candidate key.
What is entity integrity? - - ANSWER ->-Entity integrity is the
condition in which each row (entity instance or tuple) in the
table has it's own unique identity. This requires that all values
in the primary key be unique and that the primary key cannot
be null.
What is a null? - - ANSWER ->-A null is the absence of a data
value. A null should be avoided whenever possible. In fact, you
can set a rule that prevents an attribute from being null. A null
can create an issue when a function like average is used.
What is a foreign key? - - ANSWER ->-A foreign key is the
primary key of one table that has been placed into another
table to create a common attribute. For instance, a student id
number could be the primary key for information on a student
but a foreign key for a table containing a class roster.
What is referential integrity? - - ANSWER ->-Referential
integrity is the condition in which every reference to an entity
instance by another entity is valid. In other words, a foreign key
needs to be either null or a valid primary key in another table.
What is a primary key? - - ANSWER ->-A primary key is a
candidate key selected to uniquely identify all other attributes
in a given row and it may not contain null entries. Examples of
this include student ID's and social security numbers.
APPLICATIONS LATEST VERSION
UPDATED AND REVISED IN 2024-2025
What is a table? - - ANSWER ->-A table is a persistent
representation of a logical relation that is a relation whose
contents can be saved for permanent use.
What are the characteristics of a relational table? - - ANSWER -
>-The characteristics of a relational table are that a table is
perceived as a two-dimensional structure composed of rows
and columns, each row (tuple) represents a single entity
occurrence within the set, each column represents an attribute,
each column has a distinct name, each intersection of a row
and column represents a single data value, all values in a
column must be of the same data format, the order of the rows
and columns don't matter to the DBMS, and
each table must have an attribute (or combination of
attributes) that uniquely identifies each row (tuple).
What is a tuple? - - ANSWER ->-A tuple is a row that represents
a single entity occurrence within a set.
What are records? - - ANSWER ->-A record is the same as a
tuple (row).
,What is a field? - - ANSWER ->-A field is a column.
What is a key? - - ANSWER ->-A key consists of one or more
attributes that determine other attributes. For example, a
social security number identifies all of the other attributes
related to that person.
What is determination? - - ANSWER ->-Determination is the
state in which knowing the value of one attribute allows you to
determine the value of another attribute. For example, if you
know a key, you can find other information.
What is functional dependence? - - ANSWER ->-Functional
dependence is when knowing the value of one or more
attributes lets you know the value of the other attributes. For
example, knowing the first name and the social security
number would let you find the person's last name.
What is full functional dependence? - - ANSWER ->-Full
functional dependence is when knowing the value of one or
more attributes lets you know the value of other attributes and
the value of the known attributes are NEEDED to find the other
attributes. For example, a social security number lets you find
the first and last name of someone. This is full functional
dependence. If it was a social security number and a first name
this would just be functional dependence because the first
name is not required to look up the last name. All you need is
the SSN.
,What is a determinant? - - ANSWER ->-A determinant is an
attribute whose value determines the value of other attributes.
For example, a social security number could be the determinant
for your last name.
What is a dependent? - - ANSWER ->-A dependent is an
attribute whose value is determined by another attribute. For
example, you last name could be a dependent of your social
security number.
What is a composite key? - - ANSWER ->-A composite key is a
key that is composed of one or more attribute. For example,
the key of your last name and you social security number could
be used to determine your first name. This would be a
composite key because you are using your last name and your
SSN in the key.
What is a superkey? - - ANSWER ->-A superkey is a key that can
uniquely identify any row in a table. Some examples of this
would be your social security number identifying a row
corresponding to your information, but a superkey isn't limited
to full functional dependence. Your SSN and your last name
used as a key would still be a superkey.
What is a candidate key? - - ANSWER ->-A candidate key is a
minimal super key. This is to say it has no extra attributes. If
you only need a social security number to identify the row
related to a person than the candidate key is the SSN. A key
, consisting of an SSN and the last name in this case would not be
a candidate key.
What is entity integrity? - - ANSWER ->-Entity integrity is the
condition in which each row (entity instance or tuple) in the
table has it's own unique identity. This requires that all values
in the primary key be unique and that the primary key cannot
be null.
What is a null? - - ANSWER ->-A null is the absence of a data
value. A null should be avoided whenever possible. In fact, you
can set a rule that prevents an attribute from being null. A null
can create an issue when a function like average is used.
What is a foreign key? - - ANSWER ->-A foreign key is the
primary key of one table that has been placed into another
table to create a common attribute. For instance, a student id
number could be the primary key for information on a student
but a foreign key for a table containing a class roster.
What is referential integrity? - - ANSWER ->-Referential
integrity is the condition in which every reference to an entity
instance by another entity is valid. In other words, a foreign key
needs to be either null or a valid primary key in another table.
What is a primary key? - - ANSWER ->-A primary key is a
candidate key selected to uniquely identify all other attributes
in a given row and it may not contain null entries. Examples of
this include student ID's and social security numbers.
