WGU C175/D426 DATA MANAGEMENT FOUNDATIONS OA EXAM Questions With Verified Answers (100% Correct) - Latest Update 2024/2025Graded 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 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 During which step in the ETL Process, is raw data aggregated? - ANSWERTransformation steps What are the 6 different data mining activities? - ANSWER- 1. Clustering & Segmentation 2. Classification Delete Define: Clustering & Segmentation - when is it helpful? - ANSWER- - Taking large entity and dividing into smaller groups of entities - Useful when unsure of what looking for Define: Classification (Data Mining) - ANSWER- - Organizing data into predefined classes Define: Estimation (Data Mining) - ANSWER- - Assigning a numeric value to an object Define: Prediction (Data Mining) - ANSWER- - Classifying objects according to an expected future behavior Define: Affinity Grouping - ANSWER- Evaluating relationships between data elements that demonstrate some kind of affinity between objects Where does affinity grouping occur in data mining? - ANSWER- Between objects What is the uniquely identifiable element about which data can be categorized in an entity-relationship diagram? - ANSWER- Entity types Which 3 rules for referential integrity are provided by modern relational database management systems? - ANSWER- Insert Update What does the DISTINCT clause do? - ANSWER- Returns only unique or 'distinct' values; Filters Data Results What does the ORDER BY clause do? - ANSWER- Modifies presentation of data results Which SQL statement alphabetizes customer names within the same satellite-office city? - ANSWER- ORDER BY SATCITY, CUSTNAME - FULL JOIN - RIGHT JOIN - INNER JOIN What are the different types of major Joins? - ANSWER- - LEFT JOIN What is a heap file? - ANSWER- A file where records can be placed anywhere in the memory What is a hash file? - ANSWER- A file that uses Hash function computation on some fields of the records, and the result of that computation determines where the record is stored What do joins do? - ANSWER- Joins *usually* compare the foreign key of one table to the primary key of another table (but can join any columns) - joining together data from two tables into one table LEFT JOIN - ANSWER- selects all the rows from the left table, and only matching rows from the right table RIGHT JOIN - ANSWER- selects all the rows from the right table, and only matching rows from the left table OUTER JOIN - ANSWER- Any join that selects unmatched rows; LEFT, RIGHT, or FULL JOINS INNER JOIN - ANSWER- Joins together only rows that match from both tables - contains no unmatched rows FULL JOIN - ANSWER- Fully joins two tables together, even unmatched rows - places a NULL in any cell that does not match the other table What is the difference between Signed and Unsigned data? - ANSWER- - SIGNED: a number that may be negative - UNSIGNED: a number that can NOT be negative CHAR vs. VARCHAR - ANSWER- - CHAR: Fixed number of characters EMAIL ME: For help with report, Assignment, Essay and thesis writing - Risk: improved visibility - Trust: greater satisfaction - VARCHAR: Variable length of characters A record consists of a: - ANSWER- set of one or more fields What functions does the DBMS perform to guarantee integrity and consistency of the data in a database? - ANSWER- - Data Integrity Management - Data storage mangagement - Security management In what two ways does a DBMS environment increase effectiveness in working with data? - ANSWER- - Enables Data Sharing - Storage of vast volumes of data A company posts an internet-based newsletter about their products. What advantage will this company gain from the relational database management system that will store customer information? - ANSWER- Improved query response time What is the method of organizing attributes into tables? - ANSWER- Data NORMALIZATION What should a company expect from implementing a business intelligence system? - ANSWER- - Financial: Increased profitability - Productivity: Increased throughput, decreased workloads What is a relational model? - ANSWER- A database model based on mathematical principles What are the 3 mathematical concepts of the relational model? - ANSWER- - Domain - Tuple - Relation Define: Domain - ANSWER- Set of values = 'Data Type' Define: Tuple - ANSWER- Finite sequence of values pulled from a fixed domain = 'Row' Define: Relation - ANSWER- A named set of tuples, all from same domain = 'Table' A tuple position is called a: - ANSWER- Attribute How is cardinality depicted in a diagram for many, one, and zero? - ANSWER- - Many = Crow's Foot - One = a bar across the end of a relationship (--||--) - Zero = Circle Difference between Unary and Binary: - ANSWER- - Unary: One entity involved in relationship (one box, one line) - Binary: Two entities (two boxes combined by one line) If an entity is mandatory, how is it depicted in an ER diagram? - ANSWER- With a single vertical line through the relationship line What does an 'M' mean when shown on an entity in an ER diagram? - ANSWERMandatory What does a 'PI' mean when shown on an entity in an ER diagram? - ANSWERPrimary Identifier - used for attribute(s) that uniquely identify the whole entity How are maxima and minima depicted in an ER diagram? - ANSWER- Maxima is the first letter/number shown (outside of the entity) and Minima is the letter next to it in parentheses Define: Singular Attribute - ANSWER- Each entity instance has at most ONE attribute instance Define: Plural Attribute - ANSWER- Each entity instance can have MANY attribute instances