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WGU C175/D426 DATA MANAGEMENT FOUNDATIONS OA EXAM NEWEST
2025/2026 ACTUAL EXAM 2 LATEST VERSIONS 455 QUESTIONS AND CORRECT
DETAILED ANSWERS WITH RATIONALES GRADED A+
Column A depends on column B means - ......ANSWER........each B value is related to at
most one A value. Columns A and B may be simple or composite.
'A depends on B' is denoted - ......ANSWER........B → A.
For small, simple databases, the database design process can be informal and
unstructured. For large, complex databases, the process has three phases:
- ......ANSWER........1. Analysis 2. Logical design 3. Physical design
When processing transactions, database systems must: - ......ANSWER........• Ensure
transactions are processed completely or not at all. • Prevent conflicts between
concurrent transactions. • Ensure transaction results are never lost.
[Logical, Physical] design affects the query result. - ......ANSWER........Logical
[Logical, Physical] design affects query processing speed but never affects the query
result. - ......ANSWER........Physical
A database model is a conceptual framework for database systems, with three parts:
- ......ANSWER........• Data structures • Operations • Rules
Hierarchical database model - ......ANSWER........• Primary data structure: Tree • Initial
product releases: 1960s • Example database system: IMS • Strengths: Fast queries,
Efficient storage
Network database model - ......ANSWER........• Primary data structure: Linked list • Initial
product releases: 1970s • Example database system: IDMS • Strengths: Fast queries,
Efficient storage
Relational database model - ......ANSWER........• Primary data structure: Table • Initial
product releases: 1980s • Example database system: Oracle Database • Strengths:
Productivity and simplicity, Transactional applications
Object database model - ......ANSWER........• Primary data structure: Class • Initial product
releases: 1990s • Example database system: Object Store • Strengths: Integration with
object-oriented programming languages
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Graph database model - ......ANSWER........• Primary data structure: Vertex and edge •
Initial product releases: 2000s • Example database system: Neo4j • Strengths: Flexible
schema, Evolving business requirements
Document database model - ......ANSWER........• Primary data structure: XML, JSON •
Initial product releases: 2010s • Example database system: MongoDB • Strengths: Flexible
schema, Unstructured and semi-structured data
The SQL language is divided into five sublanguages: - ......ANSWER........• Data Definition
Language (DDL) defines the structure of the database. • Data Query Language (DQL)
retrieves data from the database. • Data Manipulation Language (DML) manipulates data
stored in a database. • Data Control Language (DCL) controls database user access. •
Data Transaction Language (DTL) manages database transactions.
Insert a data row into table product. INSERT is a [DML, DTL, DQL, DCL, DDL] statement
that inserts data into a table. - ......ANSWER........DML
Rollback database changes. COMMIT is a [DML, DTL, DQL, DCL, DDL] statement that
saves a transaction to the database. - ......ANSWER........DTL
Select all rows from table Product. SELECT is a [DML, DTL, DQL, DCL, DDL] statement that
retrieves data from a table. - ......ANSWER........DQL
Grant all permissions to user 'tester'. GRANT is a [DML, DTL, DQL, DCL, DDL] statement
used to give permissions to users. - ......ANSWER........DCL
Create table Product. CREATE is a [DML, DTL, DQL, DCL, DDL] statement that creates a
table. - ......ANSWER........DDL
An entity-relationship model includes three kinds of objects: - ......ANSWER........• An entity
is a person, place, product, concept, or activity. • A relationship is a statement about two
entities. • An attribute is a descriptive property of an entity.
Which design type specifies database requirements without regard to a specific database
system? - ......ANSWER........Conceptual design
What characterizes the rules of relational databases? - ......ANSWER........They are logical
constraints that ensure the data is valid.
Which database system includes the World database during its installation?
- ......ANSWER........MySQL
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Which MySQL operator is the last in the order of operator precedence? [- / OR / NOT / =]
- ......ANSWER........OR
Which type of join combines two tables without comparing columns?
- ......ANSWER........CROSS
Which function is considered an aggregating function in SQL? [TRIM / MIN / REPLACE /
SUBSTRING] - ......ANSWER........MIN
Which type of join returns only the matching values when selecting rows from two or more
tables? - ......ANSWER........Inner Join
Which phrase refers to the view in which data has persisted and is automatically changed
as the underlying data is changed? - ......ANSWER........Materialized View
What describes elements such as column name and data type?
- ......ANSWER........Metadata
Which INSERT statement demonstrates valid syntax in SQL?
INSERT INTO table name (column1, column2) SET value1, value2; INSERT INTO
table_name VALUES (value1, value2); INSERT INTO table name (column1, column2)
VALUES (value1, value2); INSERT INTO table_name SET column1 = value1, column2 =
value2; - ......ANSWER........INSERT INTO table_name (column1, column2) VALUES (value1,
value2);
Which statement used to remove data from temporary tables?
- ......ANSWER........TRUNCATE
Which property specifies an expression on one or more columns of a table? [CHECK /
RESTRICT / CASCADE / UNIQUE] - ......ANSWER........CHECK
Which type of relationship is established by a foreign key in a relational database?
- ......ANSWER........One-to-many
Which statements may be rejected when a foreign key constraint is specified? [INSERT /
CHECK / SELECT / ORDER BY] - ......ANSWER........INSERT
Which key describes the unique columns in a table that do not contain a primary key?
- ......ANSWER........Candidate key
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Which type of development activity is used to convert an entity-relationship model (ERM)
into tables, columns, and keys? - ......ANSWER........Logical design
Which term addresses columns of A being a subset of the columns of B, with A always
depending on B? - ......ANSWER........Trivial dependency
Which relationship or association exists between a supertype entity and its subtype
entities? - ......ANSWER........Is A relationship
Which symbol is used in an entity-relationship (ER) diagram for an entity?
- ......ANSWER........Square
Which symbol is used in an entity-relationship (ER) diagram to indicate an attribute?
- ......ANSWER........Circle
What must be done before creating supertype and subtype entities?
- ......ANSWER........Identify entities.
Which item in an entity-relationship (ER) diagram follows the attribute name and is placed
outside of parentheses? - ......ANSWER........Attribute maximum
Which index stores column values and row pointers in a hierarchy?
- ......ANSWER........multi-level index
Which type of index refers to entries that are assigned to buckets?
- ......ANSWER........Hash index
Which type of index is a grid of bits where each index row corresponds to a unique row in a
table? - ......ANSWER........Bitmap index
Which type of join compares columns using only the = operator?
- ......ANSWER........Equijoin
Which part of a junction table in a relational database establishes a many-to-many
relationship between two tables? - ......ANSWER........Foreign key
Data - ......ANSWER........numeric, textual, visual, or audio information that describes real-
world systems.
WGU C175/D426 DATA MANAGEMENT FOUNDATIONS OA EXAM NEWEST
2025/2026 ACTUAL EXAM 2 LATEST VERSIONS 455 QUESTIONS AND CORRECT
DETAILED ANSWERS WITH RATIONALES GRADED A+
Column A depends on column B means - ......ANSWER........each B value is related to at
most one A value. Columns A and B may be simple or composite.
'A depends on B' is denoted - ......ANSWER........B → A.
For small, simple databases, the database design process can be informal and
unstructured. For large, complex databases, the process has three phases:
- ......ANSWER........1. Analysis 2. Logical design 3. Physical design
When processing transactions, database systems must: - ......ANSWER........• Ensure
transactions are processed completely or not at all. • Prevent conflicts between
concurrent transactions. • Ensure transaction results are never lost.
[Logical, Physical] design affects the query result. - ......ANSWER........Logical
[Logical, Physical] design affects query processing speed but never affects the query
result. - ......ANSWER........Physical
A database model is a conceptual framework for database systems, with three parts:
- ......ANSWER........• Data structures • Operations • Rules
Hierarchical database model - ......ANSWER........• Primary data structure: Tree • Initial
product releases: 1960s • Example database system: IMS • Strengths: Fast queries,
Efficient storage
Network database model - ......ANSWER........• Primary data structure: Linked list • Initial
product releases: 1970s • Example database system: IDMS • Strengths: Fast queries,
Efficient storage
Relational database model - ......ANSWER........• Primary data structure: Table • Initial
product releases: 1980s • Example database system: Oracle Database • Strengths:
Productivity and simplicity, Transactional applications
Object database model - ......ANSWER........• Primary data structure: Class • Initial product
releases: 1990s • Example database system: Object Store • Strengths: Integration with
object-oriented programming languages
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Graph database model - ......ANSWER........• Primary data structure: Vertex and edge •
Initial product releases: 2000s • Example database system: Neo4j • Strengths: Flexible
schema, Evolving business requirements
Document database model - ......ANSWER........• Primary data structure: XML, JSON •
Initial product releases: 2010s • Example database system: MongoDB • Strengths: Flexible
schema, Unstructured and semi-structured data
The SQL language is divided into five sublanguages: - ......ANSWER........• Data Definition
Language (DDL) defines the structure of the database. • Data Query Language (DQL)
retrieves data from the database. • Data Manipulation Language (DML) manipulates data
stored in a database. • Data Control Language (DCL) controls database user access. •
Data Transaction Language (DTL) manages database transactions.
Insert a data row into table product. INSERT is a [DML, DTL, DQL, DCL, DDL] statement
that inserts data into a table. - ......ANSWER........DML
Rollback database changes. COMMIT is a [DML, DTL, DQL, DCL, DDL] statement that
saves a transaction to the database. - ......ANSWER........DTL
Select all rows from table Product. SELECT is a [DML, DTL, DQL, DCL, DDL] statement that
retrieves data from a table. - ......ANSWER........DQL
Grant all permissions to user 'tester'. GRANT is a [DML, DTL, DQL, DCL, DDL] statement
used to give permissions to users. - ......ANSWER........DCL
Create table Product. CREATE is a [DML, DTL, DQL, DCL, DDL] statement that creates a
table. - ......ANSWER........DDL
An entity-relationship model includes three kinds of objects: - ......ANSWER........• An entity
is a person, place, product, concept, or activity. • A relationship is a statement about two
entities. • An attribute is a descriptive property of an entity.
Which design type specifies database requirements without regard to a specific database
system? - ......ANSWER........Conceptual design
What characterizes the rules of relational databases? - ......ANSWER........They are logical
constraints that ensure the data is valid.
Which database system includes the World database during its installation?
- ......ANSWER........MySQL
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Which MySQL operator is the last in the order of operator precedence? [- / OR / NOT / =]
- ......ANSWER........OR
Which type of join combines two tables without comparing columns?
- ......ANSWER........CROSS
Which function is considered an aggregating function in SQL? [TRIM / MIN / REPLACE /
SUBSTRING] - ......ANSWER........MIN
Which type of join returns only the matching values when selecting rows from two or more
tables? - ......ANSWER........Inner Join
Which phrase refers to the view in which data has persisted and is automatically changed
as the underlying data is changed? - ......ANSWER........Materialized View
What describes elements such as column name and data type?
- ......ANSWER........Metadata
Which INSERT statement demonstrates valid syntax in SQL?
INSERT INTO table name (column1, column2) SET value1, value2; INSERT INTO
table_name VALUES (value1, value2); INSERT INTO table name (column1, column2)
VALUES (value1, value2); INSERT INTO table_name SET column1 = value1, column2 =
value2; - ......ANSWER........INSERT INTO table_name (column1, column2) VALUES (value1,
value2);
Which statement used to remove data from temporary tables?
- ......ANSWER........TRUNCATE
Which property specifies an expression on one or more columns of a table? [CHECK /
RESTRICT / CASCADE / UNIQUE] - ......ANSWER........CHECK
Which type of relationship is established by a foreign key in a relational database?
- ......ANSWER........One-to-many
Which statements may be rejected when a foreign key constraint is specified? [INSERT /
CHECK / SELECT / ORDER BY] - ......ANSWER........INSERT
Which key describes the unique columns in a table that do not contain a primary key?
- ......ANSWER........Candidate key
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Which type of development activity is used to convert an entity-relationship model (ERM)
into tables, columns, and keys? - ......ANSWER........Logical design
Which term addresses columns of A being a subset of the columns of B, with A always
depending on B? - ......ANSWER........Trivial dependency
Which relationship or association exists between a supertype entity and its subtype
entities? - ......ANSWER........Is A relationship
Which symbol is used in an entity-relationship (ER) diagram for an entity?
- ......ANSWER........Square
Which symbol is used in an entity-relationship (ER) diagram to indicate an attribute?
- ......ANSWER........Circle
What must be done before creating supertype and subtype entities?
- ......ANSWER........Identify entities.
Which item in an entity-relationship (ER) diagram follows the attribute name and is placed
outside of parentheses? - ......ANSWER........Attribute maximum
Which index stores column values and row pointers in a hierarchy?
- ......ANSWER........multi-level index
Which type of index refers to entries that are assigned to buckets?
- ......ANSWER........Hash index
Which type of index is a grid of bits where each index row corresponds to a unique row in a
table? - ......ANSWER........Bitmap index
Which type of join compares columns using only the = operator?
- ......ANSWER........Equijoin
Which part of a junction table in a relational database establishes a many-to-many
relationship between two tables? - ......ANSWER........Foreign key
Data - ......ANSWER........numeric, textual, visual, or audio information that describes real-
world systems.
