/
Dimensional Modeling
Save to my account
Sign up
Dimensional Modeling
View
Lecture 3_ Kimball Lifecycle and Dimensional Modelling_DWM.pptx_removed.pdf Flashcards
Study
1
Question
What is Dimensional Data Modeling?
Answer
Dimensional data modeling is an analytical approach used in databases and data warehouses for organizing and categorizing facts into dimension tables.
2
Question
What are the main objectives of Dimensional Modeling?
Answer
Dimensional Modeling addresses delivering data that's understandable to business users and delivering fast query performance.
3
Question
What is special about Dimensional Modeling?
Answer
Dimensional Modeling enables fast retrieval of information from large datasets by providing a structure that separates out unrelated or inconsequential data from the main body.
4
Question
How does Dimensional Modeling assist in analysis?
Answer
The dimensional model helps identify relationships between different types of data, allowing for deeper analysis of trends and patterns.
5
Question
What are the important concepts to understand in Dimensional Modeling?
Answer
Important concepts include Fact Tables, Dimension Tables, and Star Schema.
6
Question
What does a Fact Table store?
Answer
A fact table in a dimensional model stores the performance measurements resulting from an organization's business process events.
7
Question
What is the grain in a Fact Table?
Answer
The grain refers to the specific level of detail of the data in each row, such as one row per product sold on a sales transaction.
8
Question
What is a core tenet of Dimensional Modeling regarding measurement rows?
Answer
All the measurement rows in a fact table must be at the same grain.
9
Question
What is the relationship between Fact Tables and Dimension Tables?
Answer
All fact tables have two or more foreign keys that connect to the dimension tables' primary keys.
10
Question
What does it mean for tables to satisfy referential integrity?
Answer
When all the keys in the fact table correctly match their respective primary keys in the corresponding dimension tables, the tables satisfy referential integrity.
11
Question
What is a primary key in a Fact Table?
Answer
The fact table generally has its own primary key composed of a subset of the foreign keys, known as a composite key.
12
Question
What type of relationships do Fact Tables express?
Answer
Fact tables express many-to-many relationships.
13
Question
What are Dimension Tables in relation to Fact Tables?
Answer
Dimension tables are integral companions to a fact table and contain the textual context associated with a business process measurement event.
14
Question
What kind of information do Dimension Tables provide?
Answer
Dimension tables describe the who, what, where, when, how, and why associated with the event.
15
Question
How many attributes can a Dimension Table have?
Answer
It is not uncommon for a dimension table to have 50 to 100 attributes.
16
Question
How do Dimension Tables compare to Fact Tables in terms of rows?
Answer
Dimension tables tend to have fewer rows than fact tables but can be wide with many large text columns.
17
Question
How is a Dimension Table defined?
Answer
Each dimension is defined by a single primary key which serves as the basis for referential integrity with any given fact table to which it is joined.