WGU C175-D426 DATA MANAGEMENT

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WGU C175-D426 DATA MANAGEMENT

FOUNDATIONS OA EXAM 2024 ACTUAL EXAM

2 LATEST VERSIONS 300 QUESTIONS AN D

CORRECT DETAILED ANSWERS WITH

RATIONALES CORRECT AND VERIFIED

ANSWERS) ALREADY GRADED A+

What does cardinality refer to? How does it appear on ER diagram? - ANSWER✅✅Refers to the MAXIMUM number of times an instance in one entity can be associated with instance of another entity (Maxima) Appears as a 1 or M on the relationship line, closest to entity What does modality refer to? How does it appear on ER diagram? - ANSWER✅✅Refers to the MINIMUM number of times an instance in one entity can be associated with instance of another entity (minima) Appears as a 0 or 1 on the relationship line, next to cardinality Define: Referential Integrity - ANSWER✅✅Requires that ALL foreign key values must either be fully NULL or match some primary key value

• Ways Referential Integrity can be violated: - ANSWER✅✅1. Primary key is updated
• Foreign key is updated
• Row containing primary key is DELETED
• Row containing foreign key is INSERTED 1 / 4

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• Actions to Correct Referential Integrity Violation: - ANSWER✅✅1. RESTRICT - rejects an

insert, update, or delete

• SET NULL - sets invalid foreign keys to null
• SET DEFAULT - sets invalid foreign keys to a default primary value
• CASCADE - propagates primary key changes to foreign keys

What is an important aspect to referential integrity? - ANSWER✅✅reference to data in one relation is based on values in another relation What is a broad definition of data? - ANSWER✅✅Raw facts captured on printed or digital media What are data? - ANSWER✅✅Facts that are collected and stored in a database system What is a determining characteristic of unstructured data? - ANSWER✅✅It does not follow a data model What is true about flat files? - ANSWER✅✅- They contain no internal hierarchical organization How were data retrieved before database management systems? - ANSWER✅✅Sequentially from simple files What is an attribute or group of attributes that uniquely identify a tuple in a relation? - ANSWER✅✅Primary Key What is necessary for a primary key in one relation of a database to match with its corresponding foreign key in another relation of the same database? - ANSWER✅✅A domain of values 2 / 4

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What uniquely identifies each entity in a collection of entities but is not the primary key? - ANSWER✅✅Alternate Key What is the term for a set of columns in a table that can uniquely identify any record in that table without referring to other data? - ANSWER✅✅Candidate Key What happens to the original data in database indexing? - ANSWER✅✅It is copied to the index Why are indexes created in a physical database design? - ANSWER✅✅To retrieve data DIRECTLY using a pointer Why is an index created on a database column? - ANSWER✅✅To optimize data retrievals Define: Functional Dependency - ANSWER✅✅Each value of a column relates to at MOST one value of another column Dependence of one column on another What term is used to describe: a value of one particular attribute associated with a specific single value of another attribute? - ANSWER✅✅Functional Dependency Rules/Appearance of First Normal Form - ANSWER✅✅- All non-key columns depend on primary key

• Each table cell contains one value
• A table with no duplicate rows

Rules/Appearance of Second Normal Form - ANSWER✅✅- When all non-key columns depend on the WHOLE primary key

• Must be in 1NF 3 / 4

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• Non-key column can not depend on just one part of a composite key - a single primary key is

automatically in 2NF Rules/Appearance of Third Normal Form - ANSWER✅✅- All non-key columns depend ONLY on the primary key

• Tables are totally free of data redundancy

What are the 4 ways that operational and analytical databases differ? - ANSWER✅✅- Volatility

• Detail
• Scope
• History

Define: Volatility; How it applies to Operational? Analytical? - ANSWER✅✅- Database updates in real time

• Operational Data is Volatile
• Analytical Data is NOT Volatile

Define: Detail; How it applies to operational and analytical DB? - ANSWER✅✅- A database that keeps record of individual transactions; line items

- Operational: Detailed

- Analytical: Detailed

Define: Scope; How it applies to operational and analytical DB? - ANSWER✅✅- How far a database can reach

- Operational: incompatible

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