WGUC175/D426 DATA MANAGEMENT FOUNDATIONS OA ACTUAL 2025/2026 EXAM 2 LATEST VERSIONS 300 Q&A

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2 WGUC175/D426DATA MANAGEMENT FOUNDATIONS OA EXAM ACTUAL EXAM 2 LATEST VERSIONS 300 QUESTIONS AND CORRECT DETAILED ANSWERS WITH RATIONALES(100%CORRECT AND VERIFIED ANSWERS)LATEST2024/2025| ALREADY GRADEDA+ VERSION A What does modality refer to? How does it appear on ER diagram? - ANSWERRefers 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 4 Ways Referential Integrity can be violated: - ANSWER- 1. Primary key is updated 2. Foreign key is updated 3. Row containing primary key is DELETED 4. Row containing foreign key is INSERTED 4 Actions to Correct Referential Integrity Violation: - ANSWER- 1. RESTRICT rejects an insert, update, or delete 2. SET NULL - sets invalid foreign keys to null 3. SET DEFAULT - sets invalid foreign keys to a default primary value 4. 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 Stuvia.com - The Marketplace to Buy and Sell your Study Material 3 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? - ANSWERSequentially 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 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 4 Dependence of one column on another 5 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 - 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- Volat ility - 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 - Analytical: Enterprise-Wide/Summary Stuvia.com - The Marketplace to Buy and Sell your Study Material