22,294 research outputs found

    Why is the snowflake schema a good data warehouse design?

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    Database design for data warehouses is based on the notion of the snowflake schema and its important special case, the star schema. The snowflake schema represents a dimensional model which is composed of a central fact table and a set of constituent dimension tables which can be further broken up into subdimension tables. We formalise the concept of a snowflake schema in terms of an acyclic database schema whose join tree satisfies certain structural properties. We then define a normal form for snowflake schemas which captures its intuitive meaning with respect to a set of functional and inclusion dependencies. We show that snowflake schemas in this normal form are independent as well as separable when the relation schemas are pairwise incomparable. This implies that relations in the data warehouse can be updated independently of each other as long as referential integrity is maintained. In addition, we show that a data warehouse in snowflake normal form can be queried by joining the relation over the fact table with the relations over its dimension and subdimension tables. We also examine an information-theoretic interpretation of the snowflake schema and show that the redundancy of the primary key of the fact table is zero

    Bridging the Data Divide: Understanding State Agency and University Research Partnerships within SLDS

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    This report examines this question through an analysis of state agency-university researcher partnerships that exist in State Longitudinal Data Systems (SLDS). Building state agency-university researcher partnerships is an important value of SLDS. To examine state agency-university researcher partnerships within SLDS, our analysis is guided by the following set of questions based on 71 interviews conducted with individuals most directly involved with SLDS efforts in Virginia, Maryland, Texas and Washington. The findings from this analysis suggest that each stateā€™s SLDS organization and governance structure includes university partners in differing ways. In general, stronger partnership efforts are driven by legislative action or executive-level leadership. Regardless of structure, the operation of these partnerships is shaped by the agencyā€™s previous experience and cultural norms surrounding the value and inclusion of university researchers

    Bridging the Data Divide: Understanding State Agency and University Research Partnerships within SLDS

    Get PDF
    This report examines this question through an analysis of state agency-university researcher partnerships that exist in State Longitudinal Data Systems (SLDS). Building state agency-university researcher partnerships is an important value of SLDS. To examine state agency-university researcher partnerships within SLDS, our analysis is guided by the following set of questions based on 71 interviews conducted with individuals most directly involved with SLDS efforts in Virginia, Maryland, Texas and Washington. The findings from this analysis suggest that each stateā€™s SLDS organization and governance structure includes university partners in differing ways. In general, stronger partnership efforts are driven by legislative action or executive-level leadership. Regardless of structure, the operation of these partnerships is shaped by the agencyā€™s previous experience and cultural norms surrounding the value and inclusion of university researchers

    Implementing data-driven decision support system based on independent educational data mart

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    Decision makers in the educational field always seek new technologies and tools, which provide solid, fast answers that can support decision-making process. They need a platform that utilize the studentsā€™ academic data and turn them into knowledge to make the right strategic decisions. In this paper, a roadmap for implementing a data driven decision support system (DSS) is presented based on an educational data mart. The independent data mart is implemented on the studentsā€™ degrees in 8 subjects in a private school (Al-Iskandaria Primary School in Basrah province, Iraq). The DSS implementation roadmap is started from pre-processing paper-based data source and ended with providing three categories of online analytical processing (OLAP) queries (multidimensional OLAP, desktop OLAP and web OLAP). Key performance indicator (KPI) is implemented as an essential part of educational DSS to measure school performance. The static evaluation method shows that the proposed DSS follows the privacy, security and performance aspects with no errors after inspecting the DSS knowledge base. The evaluation shows that the data driven DSS based on independent data mart with KPI, OLAP is one of the best platforms to support short-to-long term academic decisions

    Factors in the Design and Development of a Data Warehouse for Academic Data.

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    Data warehousing is a relatively new field in the realm of information technology, and current research centers primarily around data warehousing in business environments. As new as the field is in these environments, only recently have educational institutions begun to embark on data warehousing projects, and little research has been done regarding the special considerations and characteristics of academic data, and the complexity of analyzing such data. Educational institutions measure success very differently from business-oriented organizations, and the analyses that are meaningful in such environments pose very unique and intricate problems in data warehousing. This research describes the process of developing a data warehouse for a community college, focusing on issues specific to academic data

    TLAD 2011 Proceedings:9th international workshop on teaching, learning and assesment of databases (TLAD)

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    This is the ninth in the series of highly successful international workshops on the Teaching, Learning and Assessment of Databases (TLAD 2011), which once again is held as a workshop of BNCOD 2011 - the 28th British National Conference on Databases. TLAD 2011 is held on the 11th July at Manchester University, just before BNCOD, and hopes to be just as successful as its predecessors.The teaching of databases is central to all Computing Science, Software Engineering, Information Systems and Information Technology courses, and this year, the workshop aims to continue the tradition of bringing together both database teachers and researchers, in order to share good learning, teaching and assessment practice and experience, and further the growing community amongst database academics. As well as attracting academics from the UK community, the workshop has also been successful in attracting academics from the wider international community, through serving on the programme committee, and attending and presenting papers.Due to the healthy number of high quality submissions this year, the workshop will present eight peer reviewed papers. Of these, six will be presented as full papers and two as short papers. These papers cover a number of themes, including: the teaching of data mining and data warehousing, databases and the cloud, and novel uses of technology in teaching and assessment. It is expected that these papers will stimulate discussion at the workshop itself and beyond. This year, the focus on providing a forum for discussion is enhanced through a panel discussion on assessment in database modules, with David Nelson (of the University of Sunderland), Al Monger (of Southampton Solent University) and Charles Boisvert (of Sheffield Hallam University) as the expert panel
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