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    Intelligent approach to automated star-schema construction using a knowledge base
    (2021-11-15)
    Sanprasit, Non
    ;
    Jampachaisri, Katechan
    ;
    Titijaroonroj, Taravichet
    ;
    Kesorn, Kraisak
    Most data-warehouse construction processes are performed manually by experts, which is laborious, time-consuming, and prone to error. Furthermore, special knowledge is required to design complex multidimensional models, such as a star schema. This predicament has motivated computer scientists to propose automation techniques to generate such models. For this reason, we present a new strategy that incorporates knowledge-based models into a framework, named the Semantic-based Star-schema Designer, that assists the automation of star schema construction. Our models provide reasoning capabilities needed by star schema designs, including those that can disambiguate heterogeneous terms, detect appropriate data types and attribute sizes, and organize data hierarchies to support online analytical processes. We also propose strategies to overcome the uncertainty arising when attribute names are not available in the data source. The names of unknown attributes are thus predicted using an arithmetic coding technique to infer column names. Our system also generates star schema from semi-structured data (e.g., comma-separated-value files and spreadsheets), which do not provide primary keys, foreign keys, or relationship cardinalities between tables. Our framework facilitates star schema construction and their relationship information without human intervention using homegrown algorithms. Experiments demonstrate that our technique predicts column names and data types that enable the effective generation of star schema better than baseline approaches.
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    A semantic approach to automated design and construction of star schemas
    (2021-07-12)
    Sanprasit, Non
    ;
    Titijaroonroj, Taravichet
    ;
    Kesorn, Kraisak
    Designing a star schema is a complex and time-consuming process requiring an expert to perform several tasks such as denormalization, dimension design, and construction of fact tables. This study presents a method to automatically design and generate star schema models, or so-called multidimensional models. We first introduce a method to incorporate a novel knowledge-based framework to enable an automation system to construct dimensional and fact tables as well as measures, which are the key elements of star schema models. The proposed framework provides a capability of column name identification using the arithmetic coding approach and measures identification using a natural language processing framework (NLP), resulting in dimensions and fact tables being constructed automatically without human intervention. Although the current version of our system is limited to reading data from semi-structured datasets such as CSV files and spreadsheets, the experimental results demonstrate that our framework can generate a star schema effectively, and can support online analytical processing (OLAP) operations. The experimental results show that our method is superior to other conventional approaches, achieving 96.67% accuracy for numerical data, higher than any of the prior models used for comparison.
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    Extract transfer load considerations of temporal data sources to data warehouses
    (2019-01-01)
    Phungtua-Eng, Thanapol
    ;
    Chittayasothorn, Suphamit
    Data warehouses are databases which store integrated enterprise-level information from information system data sources across the organization. These data sources may employ different database management systems, use different data formats, and use different value coding standards. Integrated data availability at the enterprise level from such diverse data sources requires transfers from transactional data sources, transforms them to the standard format, and loads them into the data warehouse. This process is known as the Extract Transform Load (ETL) process. At present, temporal databases which support validtime are available and temporal extensions to SQL are standard features since SQL 2011. The challenge is the temporal feature of temporal databases is different from the time dimension of conventional data warehouses. Thus specialized ETL procedures are required in the case that temporal databases are used as the data sources of data warehouses. In this paper, ETL process considerations for temporal databases sources are presented.