Data-Management-Foundations Exam Dumps - WGU Data Management – Foundations Exam

The % operator in MySQL is known as themodulus operator. It returns theremainderof a division operation between two numbers.

Example:

sql

SELECT 10 % 3; -- Output: 1 (10 divided by 3 gives remainder 1)

Option A (Incorrect):Raising a number to a power is done using the POW() function or ^ in some SQL dialects.

Option B (Incorrect):The = operator is used forequality comparisons, not %.

Option C (Correct):Themodulus operator (%)finds the remainder when one number is divided by another.

Option D (Incorrect):Subtraction is performed using the - operator.

Thesecond step in implementing relationshipsis definingone-to-one (1:1) relationshipsbetween entities.

Example Usage:

Example of a 1:1 relationship:

sql

CREATE TABLE Employees (

EmpID INT PRIMARY KEY,

Name VARCHAR(50)

);

CREATE TABLE EmployeeDetails (

EmpID INT PRIMARY KEY,

Address VARCHAR(255),

FOREIGN KEY (EmpID) REFERENCES Employees(EmpID)

);

Here, eachemployee has exactly one detail record, creating a1:1 relationship.

Why Other Options Are Incorrect:

Option A (Implement weak entities) (Incorrect):Weak entities rely on aforeign keyand are implementedlater.

Option C (Implement subtype entities) (Incorrect):Subtypes arespecial casesandnot implemented in the second step.

Option D (Specify cascade) (Incorrect):Cascade rules (ON DELETE, ON UPDATE)are defined duringforeign key implementation, not in the second step.

Thus, the correct answer isImplement one-one relationships, as it is thenext logical stepafter defining entities.

Avalid SELECT statementin SQL follows this basic syntax:

sql

SELECT column1, column2

FROM table_name

WHERE condition;

The correct optionDfollows this syntaxcorrectly.

Why Other Options Are Incorrect:

Option A (Incorrect):SQL does not usedouble quotes(") around column/table names unless explicitly required in some databases.

Option B (Incorrect):The WHERE clausemust appear after the FROM clause.

Option C (Incorrect):ALL isnota valid keyword in standard SQL queries.

Thus,Option Dfollows the correct SQL syntax.

In SQL, aprimary key is explicitly defined using the PRIMARY KEY keywordwhen creating a table.

Example Usage:

sql

CREATE TABLE Products (

ProductID INT PRIMARY KEY,

Name VARCHAR(100),

Price DECIMAL(10,2)

);

Here,PRIMARY KEY is the SQL keyword that designates ProductID as the primary key.

Why Other Options Are Incorrect:

Option A (Formula in SQL) (Incorrect):SQLdoes not use formulas to define primary keys.

Option C (Bold typeface) (Incorrect):SQL syntax does not rely on text formatting.

Option D (Diamond symbol) (Incorrect):ER diagramsmight use symbols, but SQLdoes not use diamonds to indicate keys.

Thus, the correct answer isSQL keyword, as primary keys are explicitly defined using PRIMARY KEY.

TheABS()function in SQL returns theabsolute valueof a given number, effectively measuring itsdistance from zero.

Example Usage:

sql

SELECT ABS(-50), ABS(50);

Result:

50 | 50

This function ensures that numbers arealways positive, regardless of their original sign.

Why Other Options Are Incorrect:

Option A (CONCAT) (Incorrect):Used tocombine strings(not numbers).

Option B (LOWER) (Incorrect):Converts text tolowercase, not numerical operations.

Option C (FROM) (Incorrect):Part of SELECT FROM queries,not a function.

Thus, the correct choice isABS(), which computes the absolute value of a number.

TheMERGEstatement, also known asUPSERT, combinesINSERT, UPDATE, and DELETEoperations into asingle statementbased on a given condition. It is commonly used indata warehouses and large-scale databases.

Example Usage:

sql

MERGE INTO Employees AS Target

USING NewEmployees AS Source

ON Target.ID = Source.ID

WHEN MATCHED THEN

UPDATE SET Target.Salary = Source.Salary

WHEN NOT MATCHED THEN

INSERT (ID, Name, Salary) VALUES (Source.ID, Source.Name, Source.Salary);

If a match is found, the UPDATE clause modifies the existing record.

If no match is found, the INSERT clause adds a new record.

Why Other Options Are Incorrect:

Option A (INTO) (Incorrect):Used in INSERT INTO, butdoes not combine operations.

Option B (JOIN) (Incorrect):Used to combine rows from multiple tables, butnot for merging data.

Option D (DROP) (Incorrect):Deletes database objects liketables, views, and indexes, butdoes not merge data.

Thus, the correct answer isMERGE, as itcombines inserts, updates, and deletes into a single operation.

Databases need to supportApplication Programming Interfaces (APIs)to enable seamless integration withgeneral-purpose programming languageslike Python, Java, and C#. APIs likeODBC (Open Database Connectivity) and JDBC (Java Database Connectivity)allow applications to interact with databases without requiring complex SQL commands.

Option A (Incorrect):Thestorage manageris responsible for managing low-levelfile system operations, but it does not simplify SQL integration with programming languages.

Option B (Incorrect):The ability toreverse results(e.g., using ORDER BY DESC) is a SQL feature but is unrelated to integration with programming languages.

Option C (Incorrect):Thequery processoroptimizes and executes SQL queries but does not provide an interface for application development.

Option D (Correct):APIsallow databases to be accessed easily from different programming environments, simplifying integration.

Information independencerefers to theseparation between data storage and data access. It allows a database’slogical structureto be modifiedwithout affecting existing applications.

Types of Information Independence:

Logical Data Independence→ Ability to change theconceptual schema(e.g., renaming columns, adding new attributes)without modifying applications.

Physical Data Independence→ Ability to change thephysical storage structure(e.g., indexing, partitioning)without affecting queries.

Example of Logical Data Independence:

Anew columnis added to the Customers table, but existing queriesstill work without modification.

Example of Physical Data Independence:

Data is moved to SSD storagefor performance improvement, but queriesrun the same way.

Why Other Options Are Incorrect:

Option A (Incorrect):Changing thedatabase type(e.g., MySQL to PostgreSQL) isnotinformation independence.

Option B (Incorrect):Making changes toqueriesis unrelated to database independence.

Option C (Incorrect):Interchanging databases is related todata portability, notinformation independence.

Thus, the correct answer isD - An ability to change the organization of data, asinformation independenceensuresmodifications do not disrupt database operations.