DOCSLIB.ORG

Aalborg Universitet Modeling, Annotating, and Querying Geo

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Aalborg Universitet Modeling, Annotating, and Querying Geo Aalborg Universitet Modeling, Annotating, and Querying Geo-Semantic Data Warehouses Gür, Nurefsan Publication date: 2020 Document Version Publisher's PDF, also known as Version of record Link to publication from Aalborg University Citation for published version (APA): Gür, N. (2020). Modeling, Annotating, and Querying Geo-Semantic Data Warehouses. Aalborg Universitetsforlag. Ph.d.-serien for Det Tekniske Fakultet for IT og Design, Aalborg Universitet General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. ? Users may download and print one copy of any publication from the public portal for the purpose of private study or research. ? You may not further distribute the material or use it for any profit-making activity or commercial gain ? You may freely distribute the URL identifying the publication in the public portal ? Take down policy If you believe that this document breaches copyright please contact us at [email protected] providing details, and we will remove access to the work immediately and investigate your claim. Downloaded from vbn.aau.dk on: October 04, 2021 Modeli NG , , aNN ModeliNG, aNNotatiNG, otati aNd QueryiNG Geo-SeMaNtic NG data WarehouSeS , a , N d Queryi d by NurefşaN Gür NG DISSERTATION SUBMITTED 2020 Geo-Se M a N tic tic d ata Warehou ata S e S Nurefşa N Gür IT BI D C Modeling, Annotating, and Querying Geo-Semantic Data Warehouses Ph.D. Dissertation Nuref¸sanGür Dissertation submitted January, 2020 A thesis submitted to the Technical Faculty of IT and Design at Aalborg Uni- versity (AAU) and the Faculty of Engineering at Université Libre de Bruxelles (ULB), in partial fulfilment of the requirements within the scope of the IT4BI- DC programme for the joint Ph.D. degree in Computer Science. The thesis is not submitted to any other organization at the same time. Dissertation submitted: January, 2020 AAU PhD Supervisor: Prof. Torben Bach Pedersen Aalborg University, Denmark AAU PhD Co-Supervisor: Prof. Katja Hose Aalborg University, Denmark ULB PhD Supervisor: Prof. Esteban Zimányi Université Libre de Bruxelles, Belgium PhD committee: Associate Professor Kristian Torp (chairman) Aalborg University Professor Lars Harrie GIS Centre, Lund University Researcher Sandro Bimonte National Research Institute of Science and Technology for Environment and Agriculture (IRSTEA) ULB PhD Committee: Assoc. Prof. Stijn Vansummeren Université Libre de Bruxelles, Belgium Assoc. Prof. Mahmoud Sakr Université Libre de Bruxelles, Belgium Assoc. Prof. Kristian Torp Aalborg University, Denmark Professor Lars Harrie GIS Centre, Lund University Dr. Sandro Bimonte, National Research Institute of Science and Technology for Environment and Agriculture - IRSTEA, France PhD Series: Technical Faculty of IT and Design, Aalborg University Department: Department of Computer Science ISSN (online): 2446-1628 ISBN (online): 978-87-7210-587-1 Published by: Aalborg University Press Langagervej 2 | DK – 9220 Aalborg Ø Phone: +45 99407140 | [email protected] | forlag.aau.dk © Copyright: Nurefşan Gür Printed in Denmark by Rosendahls, 2020 Abstract Due to recent advances in Semantic Web (SW) technologies and world-wide movement on publishing Linked Open Data (LOD) by following a set of principles on the SW, many governmental organizations and public agencies have been publishing large volumes of geospatial data on the SW. This large amount of spatial data on the SW yields a need for advanced analysis. In the traditional database world, data warehouses and On-Line Analytical Process- ing (OLAP) is proven to be a well constructed and efficient way of storing and querying massive amounts of data with advanced analytical perspectives. Current state-of-the-art SW technologies support only multi-dimensional an- notation of data warehouses and querying with traditional OLAP operators over non-spatial data. To reveal new perspectives over SW data, it is impor- tant to utilize the spatial information of the data sets being published, while modeling and querying the (SW) data warehouses. Even though there are many studies around the geospatial SW, none of them addresses the multi- dimensional aspects of spatial data being published or support querying with spatial OLAP (SOLAP) operators. We believe a large number of spatial data sets on the SW can be utilized with their full potential by addressing the lack of methods, tools, and applications of spatial data warehouses on the SW. Therefore the thesis addresses several challenges related to geo-semantic data warehouses to model, query, and derive analytical perspectives over a huge amount of geo-semantic data with SOLAP operators and spatial multi- dimensional enrichment of SW data. This thesis first presents the best practices for publishing Danish govern- mental data sets from agricultural, spatial, and business domains on the SW as an initial effort to publish open governmental data as Linked Open Data in Denmark. The published LOD endpoint is queried with standard and aggre- gate query templates and evaluated against three different query processing scenarios with native RDF, relational and virtual strategies. Query perfor- mance for aggregated query templates on native RDF demonstrated signifi- cantly faster response time than the other strategies. The results establish a promising basis for geo-semantic data warehouses, as aggregate queries are fundamental in multi-dimensional models and in data warehousing. iii Next, the thesis proposes a multi-dimensional cube vocabulary for SO- LAP - QB4SOLAP as an initial step of a foundation for geo-semantic data warehouses. The thesis defines full formalizations of multi-dimensional spa- tial concepts from QB4SOLAP (such as spatial dimension hierarchies, spatial measures, aggregate functions, topological relations) in RDF format. By us- ing the QB4SOLAP vocabulary, spatial data can be annotated and published on the SW with complete spatial multi-dimensional concepts, which were not available before. Spatial multi-dimensional annotation of RDF data with QB4SOLAP overcomes several limitations of spatial analytical querying of SW data with a set of SOLAP operators (e.g., s-roll-up and s-slice), where SO- LAP operators reveal new analytical perspectives to the users. SOLAP oper- ators create a dynamic interpretation of the multi-dimensional concepts (i.e., dynamic spatial hierarchy) by employing spatial functions (e.g., distance) or topological relations (e.g., within). Due to the fact that data warehouse queries typically involve nesting of SOLAP operators, which makes it almost impossible for non-SW-experts to formulate nested SOLAP queries in native RDF query language (SPARQL), the thesis proposes algorithms for translat- ing individual and nested SOLAP queries from high-level multi-dimensional expressions into SPARQL query syntax. Furthermore, using the generation algorithms and formalizations of QB4- SOLAP and SOLAP operators, a geo-semantic OLAP tool for the SW - GeoSem- OLAP is introduced to remove the entry barrier for data warehouse users to query geo-semantic data warehouses without knowledge of RDF/SPARQL. The GeoSemOLAP tool is tested and demonstrated with a non-trivial spa- tial multi-dimensional use case, which is modeled with the QB4SOLAP vo- cabulary. By using the QB4SOLAP multi-dimensional schema definitions, GeoSemOLAP parses the use case data with corresponding spatial multi- dimensional concepts, such as spatial levels, spatial attributes, and spatial measures, which can be used as input parameters to the SOLAP operations from an intuitive and easy-to-use graphical user interface that is provided with interactive maps. The QB4SOLAP vocabulary is validated on several use cases including Danish governmental, environmental, agricultural, farming, and spatial data sets, which can be annotated with spatial multi-dimensional concepts of QB4SOLAP. By applying QB4SOLAP on complex real-world data sets from various organizations and resources, a comprehensive insight is brought on to spatial and multi-dimensional modeling of governmental data with best practices, discussions, and perspectives. In order to exploit the data with new analytical perspectives that were not available before, the use cases are queried with a set of common (individual and nested) SOLAP operators in SPARQL. Finally, the thesis addresses the lacking automated methods for spatial multi-dimensional annotations on the Semantic Web and proposes an enrich- ment framework namely RDF2SOLAP to enrich the existing RDF data cubes. The thesis proposes a set of hierarchical enrichment algorithms and a set of factual enrichment algorithms within the scope of the RDF2SOLAP enrich- ment process. In each set, there are algorithms for detecting explicit relations and discovering implicit relations between spatial level members (hierarchical enrichment) and between fact-level members (factual enrichment). Moreover, in factual enrichment, the fact schema is automatically redefined from the outcome of the instance level enrichment algorithms over fact members and level members. RDF2SOLAP enrichment process allows spatial data ware- house users to query the existing spatial RDF endpoints with SOLAP oper- ators without needing to download, convert, model and store the data in an offline spatial data warehouse. Experimental evaluation results show that the proposed framework demonstrates
Load more

Recommended publications
  • Normalized Form Snowflake Schema
    Normalized Form Snowflake Schema Half-pound and unascertainable Wood never rhubarbs confoundedly when Filbert snore his sloop. Vertebrate or leewardtongue-in-cheek, after Hazel Lennie compartmentalized never shreddings transcendentally, any misreckonings! quite Crystalloiddiverted. Euclid grabbles no yorks adhered The star schemas in this does not have all revenue for this When done use When doing table contains less sensible of rows Snowflake Normalizationde-normalization Dimension tables are in normalized form the fact. Difference between Star Schema & Snow Flake Schema. The major difference between the snowflake and star schema models is slot the dimension tables of the snowflake model may want kept in normalized form to. Typically most of carbon fact tables in this star schema are in the third normal form while dimensional tables are de-normalized second normal. A relation is danger to pause in First Normal Form should each attribute increase the. The model is lazy in single third normal form 1141 Options to Normalize Assume that too are 500000 product dimension rows These products fall under 500. Hottest 'snowflake-schema' Answers Stack Overflow. Learn together is Star Schema Snowflake Schema And the Difference. For step three within the warehouses we tested Redshift Snowflake and Bigquery. On whose other hand snowflake schema is in normalized form. The CWM repository schema is a standalone product that other products can shareeach product owns only. The main difference between in two is normalization. Families of normalized form snowflake schema snowflake. Star and Snowflake Schema in Data line with Examples. Is spread the dimension tables in the snowflake schema are normalized. Like price weight speed and quantitiesie data execute a numerical format.
    [Show full text]
  • The Design of Multidimensional Data Model Using Principles of the Anchor Data Modeling: an Assessment of Experimental Approach Based on Query Execution Performance
    WSEAS TRANSACTIONS on COMPUTERS Radek Němec, František Zapletal The Design of Multidimensional Data Model Using Principles of the Anchor Data Modeling: An Assessment of Experimental Approach Based on Query Execution Performance RADEK NĚMEC, FRANTIŠEK ZAPLETAL Department of Systems Engineering Faculty of Economics, VŠB - Technical University of Ostrava Sokolská třída 33, 701 21 Ostrava CZECH REPUBLIC [email protected], [email protected] Abstract: - The decision making processes need to reflect changes in the business world in a multidimensional way. This includes also similar way of viewing the data for carrying out key decisions that ensure competitiveness of the business. In this paper we focus on the Business Intelligence system as a main toolset that helps in carrying out complex decisions and which requires multidimensional view of data for this purpose. We propose a novel experimental approach to the design a multidimensional data model that uses principles of the anchor modeling technique. The proposed approach is expected to bring several benefits like better query execution performance, better support for temporal querying and several others. We provide assessment of this approach mainly from the query execution performance perspective in this paper. The emphasis is placed on the assessment of this technique as a potential innovative approach for the field of the data warehousing with some implicit principles that could make the process of the design, implementation and maintenance of the data warehouse more effective. The query performance testing was performed in the row-oriented database environment using a sample of 10 star queries executed in the environment of 10 sample multidimensional data models.
    [Show full text]
  • Chapter 7 Multi Dimensional Data Modeling
    Chapter 7 Multi Dimensional Data Modeling Fundamentals of Business Analytics” Content of this presentation has been taken from Book “Fundamentals of Business Analytics” RN Prasad and Seema Acharya Published by Wiley India Pvt. Ltd. and it will always be the copyright of the authors of the book and publisher only. Basis • You are already familiar with the concepts relating to basics of RDBMS, OLTP, and OLAP, role of ERP in the enterprise as well as “enterprise production environment” for IT deployment. In the previous lectures, you have been explained the concepts - Types of Digital Data, Introduction to OLTP and OLAP, Business Intelligence Basics, and Data Integration . With this background, now its time to move ahead to think about “how data is modelled”. • Just like a circuit diagram is to an electrical engineer, • an assembly diagram is to a mechanical Engineer, and • a blueprint of a building is to a civil engineer • So is the data models/data diagrams for a data architect. • But is “data modelling” only the responsibility of a data architect? The answer is Business Intelligence (BI) application developer today is involved in designing, developing, deploying, supporting, and optimizing storage in the form of data warehouse/data marts. • To be able to play his/her role efficiently, the BI application developer relies heavily on data models/data diagrams to understand the schema structure, the data, the relationships between data, etc. In this lecture, we will learn • About basics of data modelling • How to go about designing a data model at the conceptual and logical levels? • Pros and Cons of the popular modelling techniques such as ER modelling and dimensional modelling Case Study – “TenToTen Retail Stores” • A new range of cosmetic products has been introduced by a leading brand, which TenToTen wants to sell through its various outlets.
    [Show full text]
  • ER/Studio Enterprise Data Modeling
    ER/Studio Enterprise Data Modeling ER/Studio®, a model-driven data architecture and database design solution, helps companies discover, document, and reuse data assets. With round-trip database support, data architects have the power to thoroughly analyze existing data sources as well as design and implement high quality databases that reflect business needs. The highly-readable visual format enhances communication across job functions, from business analysts to application developers. ER/Studio Enterprise also enables team and enterprise collaboration with its repository. • Enhance visibility into your existing data assets • Effectively communicate models across the enterprise Related Products • Improve data consistency • Trace data origins and whereabouts to enhance data integration and accuracy ER/Studio Viewer View, navigate and print ER/Studio ENHANCE VISIBILITY INTO YOUR EXISTING DATA ASSETS models in a view-only environ- ment. As data volumes grow and environments become more complex corporations find it increasingly difficult to leverage their information. ER/Studio provides an easy- Describe™ to-use visual medium to document, understand, and publish information about data assets so that they can be harnessed to support business objectives. Powerful Design, document, and maintain reverse engineering of industry-leading database systems allow a data modeler to enterprise applications written in compare and consolidate common data structures without creating unnecessary Java, C++, and IDL for better code duplication. Using industry standard notations, data modelers can create an infor- quality and shorter time to market. mation hub by importing, analyzing, and repurposing metadata from data sources DT/Studio® such as business intelligence applications, ETL environments, XML documents, An easy-to-use visual medium to and other modeling solutions.
    [Show full text]
  • Advantages of Dimensional Data Modeling
    Advantages of Dimensional Data Modeling 2997 Yarmouth Greenway Drive Madison, WI 53711 (608) 278-9964 www.sys-seminar.com Advantages of Dimensional Data Modeling 1 Top Ten Reasons Why Your Data Model Needs a Makeover 1. Ad hoc queries are difficult to construct for end-users or must go through database “gurus.” 2. Even standard reports require considerable effort and detail knowledge of the database. 3. Data is not integrated or is inconsistent across sources. 4. Changes in data values or in data sources cannot be handled gracefully. 5. The structure of the data does not mirror business processes or business rules. 6. The data model limits which BI tools can be used. 7. There is no system for maintaining change history or collecting metadata. 8. Disk space is wasted on redundant values. 9. Users who might benefit from the data don’t use it. 10.Maintenance is tedious and ad hoc. 2 Advantages of Dimensional Data Modeling Part 1 3 Part 1 - Data Model Overview •What is data modeling and why is it important? •Three common data models: de-normalized (SAS data sets) normalized dimensional model •Benefits of the dimensional model 4 What is data modeling? • The generalized logical relationship among tables • Usually reflected in the physical structure of the tables • Not tied to any particular product or DBMS • A critical design consideration 5 Why is data modeling important? •Allows you to optimize performance •Allows you to minimize costs •Facilitates system documentation and maintenance • The dimensional data model is the foundation of a well designed data mart or data warehouse 6 Common data models Three general data models we will review: De-normalized Expected by many SAS procedures Normalized Often used in transaction based systems such as order entry Dimensional Often used in data warehouse systems and systems subject to ad hoc queries.
    [Show full text]
  • Bio-Ontologies Submission Template
    Relational to RDF mapping using D2R for translational research in neuroscience Rudi Verbeeck*1, Tim Schultz2, Laurent Alquier3 and Susie Stephens4 Johnson & Johnson Pharmaceutical Research and Development 1 Turnhoutseweg 30, Beerse, Belgium; 2 Welch & McKean Roads, Spring House, PA, United States; 3 1000 Route 202, Rari- tan, NJ, United States and 4 145 King of Prussia Road, Radnor, PA, United States ABSTRACT Relational database technology has been developed as an Motivation: To support translational research and external approach for managing and integrating data in a highly innovation, we are evaluating the potential of the semantic available, secure and scalable architecture. With this ap- web to integrate data from discovery research through to the proach, all metadata is embedded or implicit in the applica- clinical environment. This paper describes our experiences tion or metadata schema itself, which results in performant in mapping relational databases to RDF for data sets relating queries. However, this architecture makes it difficult to to neuroscience. share data across a large organization where different data- Implementation: We describe how classes were identified base schemata and applications are being used. in the original data sets and mapped to RDF, and how con- Semantic web offers a promising approach to interconnect nections were made to public ontologies. Special attention databases across an organization, since the technology was was paid to the mapping of experimental measures to RDF designed to function within the distributed environment of and how it was impacted by the relational schemata. the web. Resource Description Framework (RDF) and Web Results: Mapping from relational databases to RDF can Ontology Language (OWL) are the two main semantic web benefit from techniques borrowed from dimensional model- standard recommendations.
    [Show full text]
  • Round-Trip Database Support Gives ER/Studio Data Architect Users The
    Round-trip database support gives ER/Studio Data Architect users the power to easily reverse-engineer, compare and merge, and visually document data assets residing in diverse locations from data centers to mobile platforms. You’ll leverage Enterprise data as corporate asset more effectively and can be rest assured that compliance is supported for business standards and mandatory regulations—essential factors in an organizational data governance program. Automate and scale your data modeling “We had to use a tool like Visio and do everything by hand before. We’re talking about thousands of tables with subsequent relationships. Now ER/Studio automates the most time consuming tasks.” - Jason Soroko, Business Architect at Entrust Uncover your database inconsistencies “Embarcadero tools detected inconsistencies we didn’t even know existed in our systems, saving us from problems down the road.” - U.S. Bancorp Piper Jaffray The Challenge of Fully Leveraging Enterprise Data This all-too-common scenario forces non-compliance with business standards and mandatory regulations, As organizations grow and data proliferates, ad hoc systems for while preventing business executives from the benefit of storing, analyzing, and utilizing that data start to appear and incorporating all essential data in to their decision-making are generally located near to the business unit that needs it. This process. Data management professionals face three distinct practice results in disparately located databases storing different challenges: versions and formats of the same data and an enterprise that will suffer from multiple views and instances of a single data • Reduce duplication and risk associated with multiple data capture and storage environments point.
    [Show full text]
  • Query Optimizing for On-Line Analytical Processing Adventures in the Land of Heuristics
    Aalto University School of Science Master's Programme in Computer, Communication and Information Sciences Jonas Berg Query Optimizing for On-line Analytical Processing Adventures in the land of heuristics Master's Thesis Espoo, May 22, 2017 Supervisor: Professor Eljas Soisalon-Soininen Advisors: Jarkko Miettinen M.Sc. (Tech.) Marko Nikula M.Sc. (Tech) Aalto University School of Science Master's Programme in Computer, Communication and In- ABSTRACT OF formation Sciences MASTER'S THESIS Author: Jonas Berg Title: Query Optimizing for On-line Analytical Processing { Adventures in the land of heuristics Date: May 22, 2017 Pages: vii + 71 Major: Computer Science Code: SCI3042 Supervisor: Professor Eljas Soisalon-Soininen Advisors: Jarkko Miettinen M.Sc. (Tech.) Marko Nikula M.Sc. (Tech) Newer database technologies, such as in-memory databases, have largely forgone query optimization. In this thesis, we presented a use case for query optimization for an in-memory column-store database management system used for both on- line analytical processing and on-line transaction processing. To date, the system in question has used a na¨ıve query optimizer for deciding on join order. We went through related literature on the history and evolution of database technology, focusing on query optimization. Based on this, we analyzed the current system and presented improvements for its query processing abilities. We implemented a new query optimizer and experimented with it, seeing how it performed on several queries, concluding that it is a successful improvement
    [Show full text]
  • Data Modeling Immersion 3NF DV & Dimensional
    Course Description Modeling: Operational, Data Warehousing & Data Marts Operational DW DMs GENESEE ACADEMY, LLC 2013 Course Developed by: Hans Hultgren DATA MODELING IMMERSION Modeling: Operational, Data Warehousing & Data Marts Overview Data Modeling is the process of database design. As with most design processes, data modeling is both an art and a science. Art: in that it is a creative process whereby we analyze, design and model specific solutions based on unique requirements. Science: in that we apply modeling approaches, methodologies and specific modeling patterns based on the constraints, variables and performance characteristics of the database we are creating. Our operational systems (core business applications), our data warehouse, and our data marts each have very different constraints, variables and performance characteristics. This course teaches data modeling and covers the main data modeling techniques related to each of these three major architectural layers. In this class you will learn data modeling using the normalized (3NF) modeling approach for operational systems, the ensemble data vault modeling approach for the data warehouse, and the dimensional (Star Schema) modeling approach for data marts. This is a two (2) day course delivered in the classroom. 1/1/2013 | DATA MODELING IMMERSION 1 Course Description This course covers the core principles of data modeling through lectures and hands-on labs and exercises. Providing a solid overview of current techniques for modeling operational systems, data warehouses, and data marts. In covering these areas, the course considers data modeling and design using normalized data modeling 3rd Normal Form for Operational Systems, Ensemble Data Vault modeling for the Data Warehouse, and Dimensional modeling (Star Schema) for Data Marts.
    [Show full text]
  • Readings in Database Systems, 5Th Edition (2015)
    Readings in Database Systems Fifth Edition edited by Peter Bailis Joseph M. Hellerstein Michael Stonebraker Readings in Database Systems Fifth Edition (2015) edited by Peter Bailis, Joseph M. Hellerstein, and Michael Stonebraker Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://www.redbook.io/ Contents Preface 3 Background Introduced by Michael Stonebraker 4 Traditional RDBMS Systems Introduced by Michael Stonebraker 6 Techniques Everyone Should Know Introduced by Peter Bailis 8 New DBMS Architectures Introduced by Michael Stonebraker 12 Large-Scale Dataflow Engines Introduced by Peter Bailis 14 Weak Isolation and Distribution Introduced by Peter Bailis 18 Query Optimization Introduced by Joe Hellerstein 22 Interactive Analytics Introduced by Joe Hellerstein 25 Languages Introduced by Joe Hellerstein 29 Web Data Introduced by Peter Bailis 33 A Biased Take on a Moving Target: Complex Analytics by Michael Stonebraker 35 A Biased Take on a Moving Target: Data Integration by Michael Stonebraker 40 List of All Readings 44 References 46 2 Readings in Database Systems, 5th Edition (2015) Introduction In the ten years since the previous edition of Read- Third, each selection is a primary source. There are ings in Database Systems, the field of data management good surveys on many of the topics in this collection, has exploded. Database and data-intensive systems to- which we reference in commentaries. However, read- day operate over unprecedented volumes of data, fueled ing primary sources provides historical context, gives in large part by the rise of “Big Data” and massive de- the reader exposure to the thinking that shaped influen- creases in the cost of storage and computation.
    [Show full text]
  • Star Snowflake Galaxy Schema
    Star Snowflake Galaxy Schema Bloody Maynard chivvies some kitchener after reversed Adrian underlies penumbral. Crural and unsatisfactory Cat empty hydroponicallyalmost darkling, that though Whitby Hobart walk-outs instigate his hismesocarps. witchcraft overweighs. Disrupted and Londony Hayward arranging so Data Warehouse Schemas Oracle Development. Star schemas are a typical dimensional modeling construct their star schema captures a blank business process data not numeric measures within a Fact table. What three different types of schemas? What his star schema and snowflake schema with example? Fact constellation Orange Campus Africa. A claim-based Data Integration Framework for E. Q6 Fact constellation is smart good alternative to prop a Galaxy Schema b Snowflake schema c Star Schema d None of the comprehensive Answer c Star Schema. Dimension model and starsnowflake schema of blood. Connecting Fact Tables Data Warehousing BI and legitimate Science. Why OLAP is Denormalized? Tell us about your google to understand the heart: minimum and the above has better performance you with access a galaxy schema is the olap cube data from. Snowflake Schema in same Warehouse Model GeeksforGeeks. Galaxy schema contains many fact tables with what common. Senior developers insisting modelling in Power Bi should be. The Tableau Data Model Tableau Tableau Help. Unified schema and mature usually resides at my single site. Star and snowflake schemas are actually most popular multidimensional data models used for a single warehouse The crucial difference between Star schema and. Or Galaxy schema which actually contains multiple Star andor. As collection of stars hence called galaxy schema or that constellation. Star schema A state table usage the middle connected to defeat set the dimension tables Snowflake schema A refinement of star schema where some dimensional hierarchy.
    [Show full text]
  • Bigdimetl with Nosql Database
    Open Archive Toulouse Archive Ouverte OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible This is an author’s version published in: http://oatao.univ-toulouse.fr/24712 Official URL DOI : https://doi.org/10.1016/j.procs.2018.08.014 To cite this version: Mallek, Hana and Ghozzi, Faiza and Teste, Olivier and Gargouri, Faiez BigDimETL with NoSQL Database. (2018) In: 22nd International Conference on Knowledge-Based and Intelligent Information & Engineering Systems (KES 2018), 3 September 2018 - 5 September 2018 (Belgrade, Serbia). Any correspondence concerning this service should be sent to the repository administrator: [email protected] BigDimETL with NoSQL Database Hana Mallek1*, Faiza Ghozzi1, Olivier Teste2, Faiez Gargouri1 1MIRACL Laboratory, Institute of Computer Science and Multimedia Sfax, BP 1030, Tunisia 2Université de Toulouse, IRIT 5505, 118 Route de Narbonne, 31062 Toulouse, France Abstract In the last decade, we have witnessed an explosion of data volume available on the Web. This is due to the rapid technological advances with the availability of smart devices and social networks such as Twitter, Facebook, Instagram, etc. Hence, the concept of Big Data was created to face this constant increase. In this context, many domains should take in consideration this growth of data, especially, the Business Intelligence (BI) domain. Where, it is full of important knowledge that is crucial for effective decision making. However, new problems and challenges have appeared for the Decision Support System that must be addressed. Accordingly, the purpose of this paper is to adapt Extract-Transform-Load (ETL) processes with Big Data technologies, in order to support decision-making and knowledge discovery.
    [Show full text]