WGU C175 / D426 DATA MANAGEMENT FOUNDATIONS OA EXAM Questions With Verified Answers (100% Correct) Graded A+

WGU C175 / D426 DATA MANAGEMENT FOUNDATIONS OA EXAM Questions With Verified Answers (100% Correct) Graded A+. 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 S - The Marketplace to Buy and Sell your Study Material WGU C175/D426 DATA MANAGEMENT FOUNDATIONS OA EXAM Questions With Verified Answers (100% Correct) Graded A+ 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 Dependence of one column on another - Analytical: Detailed How far a database can reach - Operational: incompatible - Analytical: Enterprise-Wide/Summary Define: Scope; How it applies to operational and analytical DB? - ANSWER- - 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 S - The Marketplace to Buy and Sell your Study Material 6. Description 5. Affinity Grouping 4. Prediction 3. Estimation Define: History; How it applies to operational and analytical DB? - ANSWER- - Whether DB is current or tracks all data - Operational: Current only - Analytical: Tracks trends Data warehouses are refreshed periodically with a 5-step process: - ANSWER- 1. Extraction 2. Cleanse 3. Integrate 4. Restructure 5. Load What happens during Extraction? (ETL) - ANSWER- Data extracted and put into staging area What happens during Cleanse? (ETL) - ANSWER- Errors are eliminated from data; standard abbreviations applied What happens during Integrate? (ETL) - ANSWER- Data is put into a uniform structure; Data converted to uniform structure What happens during Restructure? (ETL) - ANSWER- Data is structured in a design that is optimal for analysis What happens during Load? (ETL) - ANSWER- Data is loaded to the data warehouse What is an issue that is focused on the 'Load' component of ETL? - ANSWERMonitor refreshing volume and frequency