INFS 360 Quiz 2
Extract data files end in what?
"tde"
Tableau workbook data files end in what
"twb"
Operational and Analytical Data Update Differences
- Data in operational systems is regularly updated by the users - the end users of analytical databases are only able to retrieve data and updates of the data by the end users are not allowed
Dimensional modeling distinguishes 2 types of tables:
- Dimensions - Facts
Tableau attributes are...
- Dimensions - Measures
A fact table contains
- Foreign keys connecting the fact table to the dimension tables - The measures related to the subject of analysis
Questions and Queries are best visualized as:
- Line Graphs - Column/bar chart - Pie Chart - Scatter Plot
Operational and analytical Data Redundancy Difference
- Operational data supports day-to-day operations so it is used by all types of employees, customers, and other users for various tactical purposes - Analytical data is used by a more narrow set of users for decision-making purposes
2 of the most typical additional attributes that can appear in the fact table are:
- Transaction identifier - Transaction time
Data warehouse is often designed and implemented to answer 2 fundamental questions:
- Who is buying what? - When and where are they doing so?
Why is data warehousing necessary?
1. Need for integrated, company-wide view of high quality information 2. Separation of operational and analytical systems and data
A calculated field is...
A derived variable based on user defined expression using existing: - measures - dimensions - other calculated fields - parameters
Tableau extract
A file created from a data source - file extension is "tde"
INDEX
A special function because it is a table calculation
Dimension Tables
Contain descriptions of the business, organization, or enterprise to which the subject of analysis belongs
Fact Tables
Contains measures related to the subject of analyziz and the foreign keys
Information Retrieval and Decision Support
DWH is a facility for getting information to answer questions of analytical and strategic nature
What emerged as the new DDS Architecture?
Data Warehouse
Dimensional Modeling
Data design methodology used for designing subject-oriented analytical databases, such as data warehouses and data marts
A typical fact table contains what kind of data?
Dynamic data
In the star schema, the chosen subject of analysis is represented by a...?
Fact Table
T/F Tableau operations change data sources
False - Tableau operations never change data sources
T/F Tableau operations change data sources
False - tableau operations DO NOT change data sources
Is Tableau Desktop a data warehouse?
No!
Is Tableau Desktop a database?
No!
The measures in the fact tables are typically...?
Numeric - intended for mathematical computation and quantitative analysis
What are the 7 different Tableau data types?
Numeric (decimal) Numeric (whole) Date and Time (timestamp) Date String Boolean Geographic
Star Schema
The result of dimensional modeling is a dimensional schema known as a star schema that contains facts and dimensions
T/F - the extract file is different from the tableau workbook file
True
Dimensions
Typically categorical data
Measures
Typically quantitative data
Surrogate Key
have no meaning or purpose except to give each dimension a new column that serves as a primary key within the dimensional model instead of the operational key - simple auto-increment integer values
Operational information (Transactional information)
the information collected and used in support of day-today operational needs - results from individual transactions like an ATM withdrawal or purchase of an airline ticket
Operation and Analytical Time-Representation Difference
-Operation data represents the current state of affairs in the real world -Analytical data can represent both the current situation and snapshots of the past
Tableau Desktop
A standalone data visualization and business intelligence software
Operational databases are...?
Application Oriented
"=" in front of the data type ("=Abc") indicates this a...
Calculated field
Approach Change
Realization that the extract processing method is not sufficient
DWH is Integrated! What does this mean?
In DWH data is completely integrated, even when the underlying sources store data differently
Operational and Analytical Difference in Frequency of Queries
Operational queries are typically issued much more often and by more users than analytical queries
Operational and Analytical Difference in Queried Amounts of Data
Operational queries typically process much smaller amounts of data than analytical queries
Subject-oriented
Refers to the difference in purpose of a traditional database system and a DWH - Tradition database system is developed in order to support a specific business operation -DWH is developed to analyze a specific business subject area
Time-variant
Refers to the fact that a DWH contains slices of data across different periods of time. With these data slices, the user can view reports based on current as well as past data.
Structured repository
Refers to the fact that a DWH is a structured data repository like any other database
Enterprise-wide
Refers to the fact that a DWH provides a company-wide view of the information it contains
Historical
Refers to the fact that a DWH typically contains several years worth of data
Analytical Information
Refers to the information collected and used for decision support of tasks requiring data analysis EX: information showing a pattern of use of ATM machines or sales trends in the airline industry
Analytical databases are...?
Subject Oriented
Operational and Analytical Data Level-Of-Detail Difference
-Operational data is more detailed than analytical data -Analytical data is often summarized and/or detailed
Data Time Horizon Difference between analytical and operational data
-Operational systems have a shorter time horizon of data than analytical systems
Data Warehouse
An enterprise-wide structured repository of subject-oriented, time-variant, historical data used for information retrieval and decision support. The data warehouse stores atomic and summary data
What contributed to the evolution of Decision Support Systems?
Approach Change (realization that extract processing was not sufficient) and Architected Environment (Analytic and operational data are different and need to be separate)
Architected Environment
Recognition that there are fundamentally 2 kinds of data: Operational and Analytical
A typical dimension contains what kind of data?
Static Data
Database Management Systems (DBMS)
Systems for transaction processing used to drive detailed operational decisions
Decision Support Systems (DSS)
Systems that facilitate data processing used to drive management decisions
For every dimension under consideration, 2 questions must be answered:
1. Can the dimension table be useful for the analysis of the chosen subject? 2. Can the dimension table be created based on existing data sources?
Blue Pills
Represent discrete variables, typically dimensions
DWH is Subject Oriented! What does this mean?
Data is organized around major subject areas of an enterprise and is therefore useful for an enterprise-wide understanding of those subjects
Green pills
Represent continuous variables, typically measures