WGU D426 V2 EXAM LATEST 2026 UPDATED QUESTIONS AND
VERIFIED 100% SOLUTIONS (2026/2027) |A+ GRADED
|GUARANTEED PASS
Relationships are named and classified by their cardinalities, which means count (as in the
number of items in a set). HAS-A relationship. Each of the three types of binary relationships
has a different cardinality. Is the maximum number of entity instances that can participate in
a relationship instance.
Maximum Cardinality
Minimum number of entity instances that must participate in a relationship instance. These
values typically assume a value of zero (optional) or one (mandatory).
Minimum Cardinality
An entity whose instances cannot exist in the database without the existence of an instance
of another entity.
Weak Entity
Can exist in the database independently.
Strong Entity
Can be exclusive or inclusive. Can be a part of an IS-A relationship.
Subtype Entities
Depicted with square corners
Tables
Indicate primary key columns
Bullets
Depict foreign keys. Starts at the foreign key and points to the referenced table. RESTRICT,
CASCADE, or SET NULL appears on the arrow, on top read left-to-right, on bottom read right-
to-left.
Arrows
States that every value of a foreign key must match a value of an existing primary key or be
fully NULL.
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, Referential Integrity
Represents an intersection of the data sets
AND
Represents a union of the data sets
OR
Used to remove unwanted database objects from the database. Will permanently remove the
object and all associated data!
DROP
Description of the structure and format of the occurrences of the entity, similar to a recipe or
architectural blueprints.
Entity Class
Eliminates redundancy by decomposing into two or more tables. To be a well-formed relation,
every determinant must be a candidate key. Any relation that is not well-formed should be
broken into two or more well-formed relations. As a general rule, a well-formed relation will
not encompass more than one business concept.
Normalization
Putting tables back together into a single table for business needs. Used in place of a join to
speed up a query, but it uses more space, data redundant, modification anomalies.
Denormalization
Multiple values removed. Only one value in each cell.
First Normal Form
No partial dependencies. All non-key columns depend on the whole primary key.
Second Normal Form
No transitive dependencies (Functional dependencies on non-primary-key attributes. Called
transitive because the primary key is a determinant for another attribute, which in turn is a
determinant for a third. Solution: Non-key determinant with transitive dependencies goes
into a new table; non-key determinant becomes primary key in the new table and remains as
a foreign key in the old table).
Third Normal Form
2|Page
VERIFIED 100% SOLUTIONS (2026/2027) |A+ GRADED
|GUARANTEED PASS
Relationships are named and classified by their cardinalities, which means count (as in the
number of items in a set). HAS-A relationship. Each of the three types of binary relationships
has a different cardinality. Is the maximum number of entity instances that can participate in
a relationship instance.
Maximum Cardinality
Minimum number of entity instances that must participate in a relationship instance. These
values typically assume a value of zero (optional) or one (mandatory).
Minimum Cardinality
An entity whose instances cannot exist in the database without the existence of an instance
of another entity.
Weak Entity
Can exist in the database independently.
Strong Entity
Can be exclusive or inclusive. Can be a part of an IS-A relationship.
Subtype Entities
Depicted with square corners
Tables
Indicate primary key columns
Bullets
Depict foreign keys. Starts at the foreign key and points to the referenced table. RESTRICT,
CASCADE, or SET NULL appears on the arrow, on top read left-to-right, on bottom read right-
to-left.
Arrows
States that every value of a foreign key must match a value of an existing primary key or be
fully NULL.
1|Page
, Referential Integrity
Represents an intersection of the data sets
AND
Represents a union of the data sets
OR
Used to remove unwanted database objects from the database. Will permanently remove the
object and all associated data!
DROP
Description of the structure and format of the occurrences of the entity, similar to a recipe or
architectural blueprints.
Entity Class
Eliminates redundancy by decomposing into two or more tables. To be a well-formed relation,
every determinant must be a candidate key. Any relation that is not well-formed should be
broken into two or more well-formed relations. As a general rule, a well-formed relation will
not encompass more than one business concept.
Normalization
Putting tables back together into a single table for business needs. Used in place of a join to
speed up a query, but it uses more space, data redundant, modification anomalies.
Denormalization
Multiple values removed. Only one value in each cell.
First Normal Form
No partial dependencies. All non-key columns depend on the whole primary key.
Second Normal Form
No transitive dependencies (Functional dependencies on non-primary-key attributes. Called
transitive because the primary key is a determinant for another attribute, which in turn is a
determinant for a third. Solution: Non-key determinant with transitive dependencies goes
into a new table; non-key determinant becomes primary key in the new table and remains as
a foreign key in the old table).
Third Normal Form
2|Page
