WGU D426 OA EXAM 2024 - 2025 ACTUAL EXAM COMPLETE 300 QUESTIONS WITH DETAILED VERIFIED ANSWERS (100% CORRECT ANSWERS) / ALREADY GRADED A+ 1. Updates data on multiple nodes of a distributed data- base. Two -phase commit (nodes receive notice of update, store update in log, send confirmation, then receive commit). Either all nodes or no nodes must be successfully updated. 2. Updates data on a single node of a distributed data - base. Databases that use this are called "eventually consistent". 3. States that a distr ibuted database cannot be Con - sistent, Available, and Petition -tolerant simutaneous - ly. Availability refers to individual nodes. Consistent database - confirms to all rules at all times. Network partition - forms when a network error prevents nodes from communicating. Petition -tolerant - database that continues to function when a network partition oc - curs. 4. Maintains two or more replicas on separate storage devices. Advantages: High availability, fast concur - rent reads, local reads. Disadvantages: Slow or incon - sistent updates. Distributed Trans - actions Local Transaction CAP Theorem Replicated data- base 5. Entire catalog resides on a single node Central Catalog 6. Copy of catalog resides on each node Replicated Cata- log 7. Volatile - Used to conduct daily business -Changes in real time -Detailed Designed for specific business function -Concerned primarily with current data 8. AKA: Reporting Data or Decision Support Data -En- terprise -wide - Used to understand, manage, and plan the business - Sum mary Updated at fixed intervals and summarized by time period -Combines data from many business functions -Usually contains current and historic data Operational Data Analytic Data 9. Data warehouse designed for specific business area Data Mart 10. Analyt ic database of raw, unprocessed data copied from multiple data sources. Data Lake 11. Optimized for analytics Data Warehouse 12. Five-step process - ETL: Extract -Transform Load 1) Extract data 2) Cleanse data 3) Integrate data 4) Re - structure data 5) Load data - Open -source ETL tools: -PowerCenter -SQL Server Integration Services -Ora- cle Data Integrator 13. AKA: Star Schema - Consists of fact and dimension tables. Fact Table - Contains numeric data used to measure business performance.. Primary key is the composite for all foreign keys referencing dimension tables. Dimension Table - Contains textual data that describes the fact data. 14. Sequence of columns in which each column has a one-many relationship to the next column. 15. A database that stores data in main memory, instead of or in addition to storage media. Ex: SQL Serv - er In-Memory OLTP - Oracle Database In-Memory - MySQL 16. A database that is packaged with a programming language. AKA: In-Process Database (Database Ar- chitecture) - SQLite - SQL Server Compa ct 17. Collection of two or more participating databases un- der a coordinating software layer called middleware. 18. Relationships are named and classified by their car - dinalities, which means count (as in the number of items in a set). HAS -A relationship. Each of the three types of binary relationships has a different cardinal - Data Warehouse Refresh Dimensional De- sign Dimension Hierar - chy In-Memory Data- bases Embedded Data- bases Federated Data- base Maximum Cardi - nality ity. Is the maximum number of entity instances that can participate in a relationship instance. 19. Minimum number of entity instances that must partic - ipate in a relationship instance. These values typical - ly assume a value of zero (optional) or one (mandato - ry). 20. An entity whose instances cannot exist in the data - base without the existence of an instance of another entity. Minimum Cardi - nality Weak Entity 21. Can exist in the database independently. Strong Entity 22. Can be exclusive or inclusive. Can be a part of an IS-A relationship. Subtype Entities 23. Depicted with square corners Tables 24. Indicate primary key columns Bullets 25. Depict foreign keys. Starts at the foreign key and points to the referenced table. RESTRICT, CASCADE, or SET NULL appears on the arrow, on top read left-to-right, on bottom read right -to-left. Arrows 26. States that every value of a foreign key must match a Referential Integri - value of an existing primary key or be fully NULL. ty 27. Represents an intersection of the data sets AND 28. Represents a union of the data sets OR 29. Used to remove unwanted database objects from the database. Will permanently remove the object and all associated data! 30. Description of the structure and format of the occur - rences of the entity, similar to a recipe or archite ctural
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