Data Warehouse Instance

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A Data Warehouse Instance is a large subject-oriented, integrated, time-varying, non-volatile analytical database that supports data warehouse tasks.



    • In computing, a data warehouse or enterprise data warehouse (DW, DWH, or EDW) is a database used for reporting and data analysis. It is a central repository of data which is created by integrating data from one or more disparate sources. Data warehouses store current as well as historical data and are used for creating trending reports for senior management reporting such as annual and quarterly comparisons.

      The data stored in the warehouse are uploaded from the operational systems (such as marketing, sales etc., shown in the figure to the right). The data may pass through an operational data store for additional operations before they are used in the DW for reporting.

      The typical ETL-based data warehouse uses staging, data integration, and access layers to house its key functions. The staging layer or staging database stores raw data extracted from each of the disparate source data systems. The integration layer integrates the disparate data sets by transforming the data from the staging layer often storing this transformed data in an operational data store (ODS) database. The integrated data are then moved to yet another database, often called the data warehouse database, where the data is arranged into hierarchical groups often called dimensions and into facts and aggregate facts. The combination of facts and dimensions is sometimes called a star schema. The access layer helps users retrieve data.[1]

      A data warehouse constructed from an integrated data source systems does not require ETL, staging databases, or operational data store databases. The integrated data source systems may be considered to be a part of a distributed operational data store layer. Data federation methods or data virtualization methods may be used to access the distributed integrated source data systems to consolidate and aggregate data directly into the data warehouse database tables. Unlike the ETL-based data warehouse, the integrated source data systems and the data warehouse are all integrated since there is no transformation of dimensional or reference data. This integrated data warehouse architecture supports the drill down from the aggregate data of the data warehouse to the transactional data of the integrated source data systems.

      Data warehouses can be subdivided into data marts. Data marts store subsets of data from a warehouse.

      This definition of the data warehouse focuses on data storage. The main source of the data is cleaned, transformed, cataloged and made available for use by managers and other business professionals for data mining, online analytical processing, market research and decision support (Marakas & O'Brien 2009). However, the means to retrieve and analyze data, to extract, transform and load data, and to manage the data dictionary are also considered essential components of a data warehousing system. Many references to data warehousing use this broader context. Thus, an expanded definition for data warehousing includes business intelligence tools, tools to extract, transform and load data into the repository, and tools to manage and retrieve metadata.

  1. Patil, Preeti S.; Srikantha Rao; Suryakant B. Patil (2011). "Optimization of Data Warehousing System: Simplification in Reporting and Analysis". International Journal of Computer Applications (Foundation of Computer Science) 9 (6): 33–37. 


  • (Mazón & Trujillo, 2009) ⇒ Jose-Norberto Mazón, and Juan Trujillo, (2009). “A Hybrid Model Driven Development Framework for the Multidimensional Modeling of Data Warehouses.” In: SIGMOD Record, 38(2).
    • Data warehouse (DW) systems provide a multidimensional (MD) view of huge amounts of historical data from operational sources, thus supplying useful information for decision makers to improve a business process in an organization. The MD paradigm structures information into facts and dimensions. A fact contains the interesting measures (fact attributes) of a business process (sales, deliveries, etc.), whereas a dimension represents the context for analyzing a fact (product, customer, time, etc.) by means of hierarchically organized dimension attributes. MD modeling requires specialized design techniques that resemble the traditional database design methods [16]. First, a conceptual design phase is performed whose output is an implementation-independent and expressive MD model for the DW. A logical design phase then aims to obtain a technology-dependent model from the previously defined conceptual MD model. This logical model is the basis for the implementation of the DW. Therefore, there are two cornerstones in MD modeling: the development of a conceptual MD model and the derivation of its corresponding logical representation.



  • (Zaiane, 1999) ⇒ Osmar Zaiane. (1999). “Glossary of Data Mining Terms." University of Alberta, Computing Science CMPUT-690: Principles of Knowledge Discovery in Databases.
    • QUOTE: Data mart: A small, single-subject warehouse used by individual departments or groups of users.
    • QUOTE: Data Warehouse: A system for storing and delivering massive quantities of data.