DATABASE 0047relational_databases_unit_5_milestone_5. UNIT 5 — MILESTONE 5 Score 12/17 | Western Governors University

Western Governors University DATABASE 0047relational_databases_unit_5_milestone_5. UNIT 5 — MILESTONE 5 Score 12/17 You passed this Milestone 12 questions were answered correctly. 5 questions were answered inco ...

Western Governors University DATABASE 0047relational_databases_unit_5_milestone_5. UNIT 5 — MILESTONE 5 Score 12/17 You passed this Milestone 12 questions were answered correctly. 5 questions were answered incorrectly. 1 What would be a reason why we may want to denormalize our database? We may want to store pre-aggregated or derived data. We want to reduce redundancy. We want to eliminate repeating groups. We want to remove multivalued dependencies. CONCEPT Denormalization 2 Is this dataset in 3NF or not? If not why not? Yes, it is in 3NF. No, it is not yet in 2NF. No, there are repeating groups. No, there is an issue with the functional dependency. CONCEPT Third Normal Form 3 What is a key feature of fourth normal form? It should be in BCNF to start with. 4NF is also focused on full functional dependency. 4NF is all about join dependencies. This normal form has the tables broken down into as many tables as possible to avoid redundancy. CONCEPT Higher Normalization 4 In each milestone, you may want or need to use the database and query tool to answer some of the questions. We suggest you open the tool in another browser tab while you are working on this assessment. https://postgres.sophia.org/ What type of cardinality is demonstrated by the following ERD? A department has a professor. A professor is part of multiple departments. A department has a professor. A professor is part of a department. A department has multiple professors. A professor is part of multiple departments. A department has multiple professors. A professor is part of a department. CONCEPT Relationships and Cardinality 5 What would need to be done to fix an issue with a chasm trap? Create a foreign key for each primary key in the relationships. Remove the middle table and connect the tables directly. The entire database design needs to be re-evaluated. Create a direct link between the two tables rather than depend on the middle relationship. CONCEPT ERD Connection Traps 6 In each milestone, you may want or need to use the database and query tool to answer some of the questions. We suggest you open the tool in another browser tab while you are working on this assessment. https://postgres.sophia.org/ What is wrong with the following ERD meant to show the attributes of an entity? The attributes are not correctly linked to the entity. The symbols used are swapped. The primary key is not indicated correctly. There is nothing wrong with the ERD. CONCEPT Adding Attributes 7 Identify the normal form in which all of the attributes are set up to be dependent on the primary key. 1NF None of the first 3 normal forms 2NF 3NF CONCEPT Normal Forms 8 In each milestone, you may want or need to use the database and query tool to answer some of the questions. We suggest you open the tool in another browser tab while you are working on this assessment. https://postgres.sophia.org/ What is wrong with the following ERD meant to show a relationship between two entities? There is no relationship between the entities. There is nothing wrong with the ERD. Both of the objects are attributes. One of the items is set up as an attribute. CONCEPT Tables as Entities 9 Is this dataset in 1NF or not? If not, why not? There are repeating groups with the actor_names and possibly the genre_names. This data set is in 1NF already. There are no foreign keys. There is no primary key. CONCEPT First Normal Form 10 What is true about normalization? Prioritize performance rather than data anomalies. Store pre-aggregated or derived data. Our database may not need to have data be inserted, updated, or deleted. You need to take into account business rules and data constraints. CONCEPT Normalization Overview 11 What is a benefit of using a lookup table? There is data modification flexibility. They resolve weak entities. They guarantee that there will be no data redundancies due to functional dependencies. They transform an M:N relationship into two 1:M relationships. CONCEPT Reference Tables 12 What is a disadvantage of reducing the complexity of data models? Faster application development Decreased redundancy Simpler application code Simpler queries CONCEPT ERD Example: Complexity 13 In each milestone, you may want or need to use the database and query tool to answer some of the questions. We suggest you open the tool in another browser tab while you are working on this assessment. https://postgres.sophia.org/ What is used to indicate a weak relationship in an ERD? Double diamond Dotted line between entities Single dotted diamond Single diamond CONCEPT Weak Relationships and Entities 14 Is this dataset in 2NF or not? If not, why not? No, there are repeating groups. No, there are no transitive functional dependencies. It is already in 2NF No, there are columns that are not dependent on the primary key. CONCEPT Second Normal Form 15 Review the sample movie ratings initial data set after 3NF. What is the relationship between table Movie and Rating? 0:1 1:1 1:M M:N CONCEPT ERD Example: Movie Ratings 16 Review the sample eCommerce ERD after 3NF. Which tables are lookup tables? Category Customer, Category PhoneType, AddressType Category, AddressType, PhoneType CONCEPT ERD Example: eCommerce 17 What type of key can be used in an associative entity? No key is needed with an associative entity. A natural primary key is generally used. A surrogate key is used. An artificial primary key is used. CONCEPT Associative Entities About Contact Us Privacy Policy Terms of Use