Data Warehouse Fundamentals

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Questions and Answers

What is a primary function of a data warehouse?

  • To support management decision making. (correct)
  • To execute real-time transactions.
  • To manage day-to-day business operations.
  • To replace operational databases.

Which characteristic distinguishes a data warehouse from an operational database?

  • Data warehouses contain real-time information.
  • Operational databases support business intelligence.
  • Data warehouses are used to run day-to-day business operations.
  • Data warehouses constitute an entire information base for all time. (correct)

In the context of data warehousing, what does it mean for data to be 'subject-oriented'?

  • The data is focused on ongoing operations.
  • The data changes frequently.
  • The data is scattered across multiple networks.
  • The data is organized around key business subjects. (correct)

What does the 'integration' characteristic refer to in the context of a data warehouse?

<p>The consolidation of data from different sources into a unified view (B)</p> Signup and view all the answers

Which of the following best describes the 'time-variant' feature of a data warehouse?

<p>Data represents information across a span of time. (D)</p> Signup and view all the answers

What does it mean for a data warehouse to be 'non-volatile'?

<p>The data cannot be overwritten or removed. (B)</p> Signup and view all the answers

Why is summarization an important aspect of data warehouses?

<p>It optimizes storage and improves query performance. (D)</p> Signup and view all the answers

Which component is responsible for extracting data from various sources in a data warehouse architecture?

<p>Data staging area (B)</p> Signup and view all the answers

If a business user requires historical summarized data presented in an elementary form, what component is required?

<p>Data Warehouse (B)</p> Signup and view all the answers

What is the role of operational database management systems such as OLTP?

<p>Running day-to-day processes of an organization. (A)</p> Signup and view all the answers

What role does metadata play in a data warehouse?

<p>It acts as a data dictionary or catalog. (A)</p> Signup and view all the answers

How does a data mart differ from a data warehouse?

<p>A data mart is a subset of a data warehouse. (C)</p> Signup and view all the answers

Which of the following is a characteristic of data in an Operational Database (OLTP)?

<p>Dynamic (D)</p> Signup and view all the answers

What distinguishes Online Analytical Processing (OLAP) from Online Transaction Processing (OLTP)?

<p>OLAP supports complex queries for analysis, while OLTP supports real-time transactions. (A)</p> Signup and view all the answers

Which of the following describes the transformation that takes place during data warehousing?

<p>Converting data into information (B)</p> Signup and view all the answers

A company is experiencing difficulty in retrieving well-documented data for analysis. According to the content, what is a potential problem?

<p>The available data is poorly documented. (C)</p> Signup and view all the answers

How does a data warehouse assist in strategic decision-making?

<p>By contributing to making strategic decisions. (B)</p> Signup and view all the answers

A company needs to analyze sales trends over the past decade. Which type of system is best suited for this task?

<p>Data warehouse (D)</p> Signup and view all the answers

What are the benefits of using a data warehouse?

<p>Better forecasting decisions based on business trends (C)</p> Signup and view all the answers

What does the term 'Data Loading' refer to in the context of data warehousing?

<p>Transferring data to data warehouse storage (A)</p> Signup and view all the answers

In the data warehousing process, what is the significance of data staging?

<p>Data Staging retrieves data from data sources (B)</p> Signup and view all the answers

What is the most appropriate system for an ATM that executes Bank transactions?

<p>OLTP System (C)</p> Signup and view all the answers

What is the purpose of information delivery in a Data Warehouse?

<p>To deliver Warehouse files to the customer as per the needs (A)</p> Signup and view all the answers

Why is it necessary to maintain separate databases, such as an OLTP system and a Data Warehouse?

<p>For functionality and differing data needs (D)</p> Signup and view all the answers

In the context of database design, what does de-normalization do in a data warehouse?

<p>It makes operations faster (A)</p> Signup and view all the answers

Which of the following best describes the role of archived data in relation to operational systems?

<p>Archived data is periodically taken for archival purposes. (A)</p> Signup and view all the answers

According to the information provided, which task is likely the responsibility of an external department regarding data?

<p>Producing statistics in their industry for external department use. (C)</p> Signup and view all the answers

According to the content, what is often a challenge in Data Warehousing in terms of Transformation?

<p>Transformation can present challenges. (C)</p> Signup and view all the answers

A business stores old data in archive files and is unable to retrieve well-documented data, what component is need?

<p>Metadata (C)</p> Signup and view all the answers

What is the primary goal of data warehousing in terms of organizational information?

<p>To maintain historical information for making appropriate decisions (B)</p> Signup and view all the answers

Which of the following statements correctly differentiates how Data and Entity modeling are used in data management?

<p>Data Modeling is for a Data Warehouse design, and Entity Modeling is for RDBMS. (B)</p> Signup and view all the answers

According to content, which statement is true about an OLTP system and Data Warehouse system?

<p>Although both serve separate functions, it is common to combine a warehouse into a system to serve the business. (D)</p> Signup and view all the answers

Barry Devlin and Paul Murphy, IBM researchers, established which data warehousing term in 1980?

<p>Business Data Warehouse (B)</p> Signup and view all the answers

The separation of an operational database and data warehouse is?

<p>Based on structure differences (D)</p> Signup and view all the answers

When we complete the structure the construction of the data warehouse and go live for the first time, this is which primary function?

<p>Data Loading (D)</p> Signup and view all the answers

Data is larger static in Data Warehouses. What does this mean?

<p>The data doesn't change as much as other systems (D)</p> Signup and view all the answers

A data warehouse is subject oriented since it provides information around ?

<p>subject, like product, customers, supplier, etc. (A)</p> Signup and view all the answers

What is the first action a firm has to do in the 3 Primary Function of Data Warehousing?

<p>Extraction (B)</p> Signup and view all the answers

Data warehousing provides businesses the understanding to analyze a large amount of what?

<p>historical (B)</p> Signup and view all the answers

Flashcards

Database

A database constitutes real-time information, used to run the business using current data.

Data warehouse (DWH)

The entire information base for all time, used as a guide on how to run the business.

Data Warehouse definition

A single, complete and consistent store of data obtained from a variety of different sources made available to end users.

Data Warehousing

The transformation of data into information, making it available to users in a timely manner to make a difference.

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Data Warehousing as a System

A relational or multidimensional database management system designed to support management decision making.

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Data Warehousing copy

A copy of transaction data specifically structured for querying and reporting.

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Data warehousing function

Assembling and managing data from various sources for the purpose of answering business questions and making decisions that were not previously possible.

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Subject-Oriented

A data warehouse is organized around subjects, focusing on providing information around a subject rather than the organization's ongoing operations.

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Integrated

Data integration refers to the technical and business processes used to combine data from multiple sources to provide a unified, single view of the data that ensures businesses describe data the same way throughout the enterprise.

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Time-Variant

Once data are periodically uploaded to the data warehouse, all time-dependent aggregations are recomputed so that it is also time-variant.

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Non-Volatile

Existing data in the warehouse are not overwritten or removed.

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Summarizes Data

Data extracted from the low level of detail found at the current, detailed level and usually is stored on disk storage.

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Goals of Data Warehousing

Help reporting as well as analysis, maintain the organization's historical information, and be the foundation for decision making.

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Business User

Business users require a data warehouse to view summarized data from the past; since these people are non-technical, the data may be presented to them in an elementary form.

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Store Historical Data

Data Warehouse is required to store the time variable data from the past; this input is made to be used for various purposes.

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Make Strategic Decisions

Strategies may depend on the data; data warehouse contributes to strategic decisions.

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For Data Consistency and Quality

Bringing the data from different sources at a commonplace, the user can effectively undertake to bring the uniformity and consistency in data.

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High Response Time

Data warehouse has to be ready for somewhat unexpected loads and types of queries, which demands a significant degree of flexibility and quick response time.

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Benefits of Data Warehouse

Understand business trends and make better forecasting decisions that are designed to perform well enormous amounts of data, as the structure of data warehouses is more accessible for end-users to navigate, understand, and query.

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Production Data

Data from the different operating systems of the enterprise.

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Internal Data

The client keeps their 'private' spreadsheets, reports, customer profiles, and sometimes even department databases in each organization.

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Archived Data

Intended to run the current business but in every operational system, we periodically take the old data and store it in archived files.

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External Data

Most executives depend on information from external sources for a large percentage of the information they use, using statistics associating to their industry produced by the external department.

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Data Extraction

This method has to deal with numerous data sources; we have to employ the appropriate techniques for each data source.

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Data Transformation

If data extraction for a data warehouse posture big challenges, data transformation presents even significant challenges.

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Data Loading

When we complete the structure and construction of the data warehouse and go live for the first time, we do the initial loading of the information into the data warehouse storage; the initial load moves high volumes of data using up a substantial amount of time.

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Data Storage

The data warehousing's split repository as the repositories for the operational systems generally include only the current data structured in highly normalized for fast and efficient processing.

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Information Delivery

Used to enable the process of subscribing for data warehouse files and having it transferred to one or more destinations according to some customer-specified scheduling algorithm.

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Metadata

Equal to the data dictionary or the data catalog in a database management system.

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Data Mart

Includes a subset of corporate-wide data that is of value to a specific group of users that are lower than data warehouses and usually contain organization.

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Data Warehouse Queries

Queries are complex because they involve the computation of large groups of data at summarized levels.

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Data Organization

Requires the use of distinctive data organization, access, and implementation method based on multidimensional views.

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Operational Database Degradation

Performing OLAP (Online Analytical Processing) queries in operational database degrade the performance of functional tasks.

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Data Warehouses

Used for analysis and decision-making in which extensive database is required, including historical data, which operational database does not typically maintain.

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Operational DB vs. Data Warehouses

separation is based on the different structures and uses of data in these systems.

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Data Warehouse Systems

serve users or knowledge workers in the purpose of data analysis and decision-making and can organize and present information in specific formats.

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OLTP System

handles with operational data that is contained in the operation of a particular system

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OLAP System

Handles with Historical Data or Archival Data.

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Operational Database (OLTP)

Used to 'run' a business.

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Data Warehouse in a Business

Helps to 'optimize' the business

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Study Notes

The Data Warehouse

  • Data warehouses constitute the entire information base for all time.
  • Databases constitute real time information.
  • Data warehouses supports data mining and business intelligence.
  • Databases are used to run the business.
  • Data warehouses are how to run the business.

The Problem With Data

  • Difficulty finding needed data, as it is scattered, with multiple versions and subtle differences.
  • Challenges in getting the data, requiring an expert.
  • Difficulty understanding data, often poorly documented.
  • Challenges in using data due to unexpected results and the need for transformation.

What is a Data Warehouse

  • Single, complete, and consistent store of data from various sources.
  • Made available to end users in a format they can understand and use in a business context.
  • Data warehousing involves transforming data into information and making it available to users in a timely manner.
  • Technique for assembling and managing data from various sources to answer business questions, facilitating previously impossible decisions.
  • Relational or multidimensional database management system designed to support management decision making. -Copy of transaction data structured for querying and reporting.

Inventor

  • Bill Inmon is known as the "Father of Data Warehouse."

Key Features

  • Subject-oriented: Provides information around a subject rather than the organization's ongoing operations -Subjects include product, customers, suppliers, sales, revenues, etc.
  • Integrated: Combines data from multiple sources to provide a unified view -Ensures business entities, data elements, characteristics, and metrics are described consistently.
  • Time-variant: Data is periodically uploaded, and time-dependent aggregations are recomputed.
  • Non-volatile: Existing data is not overwritten or removed.
  • Data is summarized from detailed levels and stored on disk.

Data Warehouses in the Market

  • Snowflake
  • Google BigQuery
  • Amazon Redshift
  • Azure Synapse Analytics
  • IBM Db2 Warehouse
  • Firebolt

History

  • The idea of data warehousing emerged in 1980.
  • Barry Devlin and Paul Murphy of IBM established the "Business Data Warehouse" concept.
  • Originally planned to support an architectural model for the flow of information from operational systems to decisional support environments.

Goals

  • Aid reporting and analysis.
  • Maintain the organization's historical information.
  • Serve as the foundation for decision-making.

Need For a Data Warehouse

  • Business users: Require summarized data presented in an accessible form.
  • Storing historical data: Needed to store time-variable data for various purposes.
  • Strategic decisions: Relies on the data to inform strategic choices.
  • Data consistency and quality: Provides uniformity by integrating data from different sources.
  • High response time: Requires flexibility and quick response to handle unexpected loads and queries.

Benefits

  • Understand business trends for better forecasting.
  • Designed to handle large data volumes efficiently.
  • Accessible structure for easy navigation, understanding, and querying.
  • Simpler queries compared to normalized databases.
  • Efficient management of information demand from many users.
  • Capabilities to analyze large amounts of historical data.

Components

  • Source Data: -Comes in 4 broad categories: Production data, Internal Data, Archived Data, External Data
  • Data Staging
  • Data Extraction: Deals with numerous data sources and requires appropriate techniques for each.
  • Data Transformation: Presents significant challenges.
  • Data Loading: Involves the initial loading of information into the data warehouse storage. Moves high volumes of data and takes a substantial amount of time.
  • Data Storage: Split Repository
  • Information Delivery:
  • Enables the process of subscribing to data warehouse files.
  • Transfers files to destinations based on a customer-specified scheduling algorithm.

Additional Components

  • Metadata: Equivalent to a data dictionary or data catalog in a database management system.
  • Data Mart:
  • Subset of corporate-wide data that is valuable to a specific group of users.
  • Smaller than data warehouses and usually contain organization.

Why a Separate Data Warehouse is Needed

  • Complex queries involving summarized data.
  • Requires distinctive data organization and access methods based on multidimensional views.
  • Online Analytical Processing (OLAP) queries in operational databases degrade performance.
  • Used for analysis and decision-making, requiring extensive historical data not maintained by operational databases.
  • Separation is due to the different structures and uses of data.
  • Distinct functionalities and data requirements necessitate separate databases.

Operational Database vs. Data Warehouse

  • The operational database is a source of information.
  • Operational databases handle detailed information and run day-to-day business operations.
  • Operational Database Management Systems are named OLTP (Online Transactions Processing Databases).
  • Data frequently changes and reflects the current value of transactions.
  • Data warehouses serve users or knowledge workers for data analysis and decision-making.
  • Data Warehouse are Online-Analytical Processing (OLAP) Systems.

OLTP vs. OLAP Systems

  • OLTP handles operational data such as ATM and bank transactions.
  • OLAP handles historical or archival data, e.g., flight reservations from 10 years ago.

Summary

  • OLTP Systems are used to "run" a business.
  • Data Warehouses help to "optimize" the business.

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