WGU WGU Data Management – Foundations Exam Data-Management-Foundations Exam Dumps: Updated Questions & Answers (October 2025)

TheUNIONkeyword in SQL is used tocombine the resultsof two or more SELECT queries into asingle result setwhile removing duplicate rows.

Example:

sql

SELECT Name FROM Employees

UNION

SELECT Name FROM Managers;

Option A (Correct):UNION combines results from multiple queries into one set,removing duplicates.

Option B (Incorrect):MERGE is not a valid SQL keyword for combining result sets (it is used insome database systems for data merging).

Option C (Incorrect):INTEGRATE is not a SQL keyword.

Option D (Incorrect):CONSOLIDATE is not an SQL keyword.

Aprimary keyuniquely identifies each row in a table. When a primary key consists ofonly one field, it is called aSimple Primary Key.

Types of Primary Keys:

Simple Primary Key (Correct Answer):

Contains onlyone column.

Example:

sql

CREATE TABLE Students (

StudentID INT PRIMARY KEY,

Name VARCHAR(50)

);

Composite Primary Key:

Usesmultiple columnsto ensure uniqueness.

Example:

sql

CREATE TABLE Orders (

OrderID INT,

ProductID INT,

PRIMARY KEY (OrderID, ProductID)

);

Surrogate Primary Key:

A system-generatedunique identifier(e.g., UUID or AUTO_INCREMENT).

Why Other Options Are Incorrect:

Option B (Duplicate) (Incorrect):A primary keymust be unique, so itcannot be duplicate.

Option C (Numeric) (Incorrect):While primary keyscan be numeric, they can also be alphanumeric (VARCHAR).

Option D (Composite) (Incorrect):Acompositekey consists ofmultiple fields, whereas a simple key isa single field.

Thus, the correct answer isSimple, since aone-field primary keyis a simple primary key.

Thecorrect syntaxfor deleting records from a table in SQL is:

sql

DELETE FROM table_name WHERE condition;

This deletesonly the rowsthat match the condition.

Example Usage:

sql

DELETE FROM Employees WHERE Salary < 30000;

Deletesall employees earning less than $30,000.

Why Other Options Are Incorrect:

Option A (Incorrect):Missing FROMkeyword. The correct syntax is DELETE FROM table_name.

Option C (Partially Correct):DELETE FROM table_name;deletes all rows, but it lacks a WHERE clause.

Option D (Incorrect):DELETE *is not validin SQL. The correct command is just DELETE FROM.

Thus, the correct answer isDELETE FROM table_name WHERE condition;.

In aone-to-many (1:M) relationship, theforeign keyis placed in thetable on the "many" sideto establish the relationship with theprimary keyof the "one" side.

Example Usage:

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CREATE TABLE Departments (

DeptID INT PRIMARY KEY,

DeptName VARCHAR(50)

);

CREATE TABLE Employees (

EmpID INT PRIMARY KEY,

Name VARCHAR(50),

DeptID INT, -- Foreign key on the "many" side

FOREIGN KEY (DeptID) REFERENCES Departments(DeptID)

);

Eachdepartmentcan havemany employees→ DeptID is aforeign keyin Employees.

Why Other Options Are Incorrect:

Option A (Reflexive relationship) (Incorrect):Refers tounary (self-referential) relationships, not 1:M relationships.

Option B (Binary relationship) (Incorrect):A binary relationship involvestwo entities, but does not define where the foreign key is stored.

Option C (Weak entity) (Incorrect):Weak entitiesdepend on a strong entity, but not all "many" sides are weak entities.

Thus, the correct answer isForeign key, as it is placed on the "many" side of the relationship.

TheCHECKconstraint is used in SQL toenforce ruleson a column's values. It ensures that data inserted into a table meets specified conditions, such as range restrictions or logical rules.

Example Usage:

sql

CREATE TABLE Employees (

ID INT PRIMARY KEY,

Name VARCHAR(50),

Salary INT CHECK (Salary BETWEEN 30000 AND 150000)

);

This constraint ensures thatsalary values fall between 30,000 and 150,000.

If an INSERT or UPDATE statement tries to set Salary = 20000, itfailsbecause it does notmeet the CHECK condition.

Why Other Options Are Incorrect:

Option B (FROM) (Incorrect):Used in SELECT statements, not for constraints.

Option C (WHERE) (Incorrect):Filters rows in queries butdoes not enforce constraints.

Option D (SET) (Incorrect):Used for updating records (UPDATE table_name SET column = value) butnot for defining constraints.

Thus,CHECK is the correct answer, as it ensures that column values remain within an expected range.

In database indexing, abranchrefers to thepath from the top-level block (root node) to a bottom-level block (leaf node)in aB-Tree or B+ Tree index structure.

Example Usage in Indexing:

AB-Tree indexorganizes data hierarchically, withbranches leading to different parts of the tree.

When searching for a record, thequery follows a branchfrom theroot node down to the correct leaf node.

Why Other Options Are Incorrect:

Option A (Fan-out) (Incorrect):Refers tohow many children a node has, not the path.

Option B (Crow’s foot) (Incorrect):Anotation used in ER diagrams, not indexing.

Option D (Sparse index) (Incorrect):A type of indexstoring only some entries, not the path itself.

Thus, the correct answer isBranch, as it defines thepath from top to bottom in a database index.

The given diagram represents a unary relationship (also called a recursive relationship), which occurs when an entity is related to itself. In this case, salespersons back each other up, meaning a salesperson is associated with another salesperson from the same entity.

Key Observations from the Diagram:

Single Entity (Salesperson)

The table contains only one entity type, Salesperson, which has attributes such as Salesperson Number, Name, Commission, Percentage, and Year of Hire.

Self-Referencing Relationship (Backs-up and Backed-up by)

The diagram shows that a salesperson can back up another salesperson.

This means that the relationship exists within the same entity rather than between two different entities.

Cardinality (One-to-One Relationship in a Unary Form)

The notation ( |—| ) in the ER diagram indicates a one-to-one recursive relationship.

One salesperson can back up only one other salesperson, and each salesperson is backed up by only one.

In SQL,literalsrepresent explicit values such asnumbers, strings, or binary datadirectly written into queries. For example:

SELECT * FROM Employees WHERE Salary > 50000;

Here, 50000 is anumeric literal.

Option A (Correct):Literalsare explicit values used in SQL queries, such as 123, 'John Doe', and TRUE.

Option B (Incorrect):Commentsare non-executable text used for documentation within SQL code, typically denoted by -- or /* ... */.

Option C (Incorrect):Identifiersare names oftables, columns, or other database objects, such as EmployeeID.

Option D (Incorrect):Keywordsare reserved words in SQL (e.g., SELECT, FROM, WHERE) that define operations and syntax.

TheORDER BYclause in SQL is used tosort query resultsinascending (ASC) or descending (DESC) order.

Example Usage:

sql

SELECT Name, Salary FROM Employees ORDER BY Salary DESC;

This retrieves all employees, sorted bysalary in descending order.

Why Other Options Are Incorrect:

Option A (BETWEEN) (Incorrect):Used for filtering ranges butdoes not order results.

Option B (DISTINCT) (Incorrect):Removes duplicate rows butdoes not control order.

Option D (LIKE) (Incorrect):Used forpattern matching, not sorting.

Thus,ORDER BY is the correct choicefor defining the sequence of query results.

Atangible entityis a real-world object that can bemeasured and storedin a database.

Example Usage:

In an inventory system,tangible entitiesinclude:

Products, Orders, Customers

Why Other Options Are Incorrect:

Option A (Logical entity) (Incorrect):Exists logically butmay not have a physical presence(e.g.,views, categories).

Option C (Virtual entity) (Incorrect):Existsonly in queries or reports, not stored as real data.

Option D (Conceptual entity) (Incorrect):Abstract idea used indesign modeling, not astored entity.

Thus, the correct answer isTangible entity, as it representsmeasurable, real-world objects.