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  2. Dummy data - Wikipedia

    en.wikipedia.org/wiki/Dummy_data

    Dummy data can be used as a placeholder for both testing and operational purposes. For testing, dummy data can also be used as stubs or pad to avoid software testing issues by ensuring that all variables and data fields are occupied. In operational use, dummy data may be transmitted for OPSEC purposes. Dummy data must be rigorously evaluated ...

  3. Star schema - Wikipedia

    en.wikipedia.org/wiki/Star_schema

    Employee dimension tables describe employees, such as sales people Range dimension tables describe ranges of time, dollar values or other measurable quantities to simplify reporting Dimension tables are generally assigned a surrogate primary key , usually a single-column integer data type, mapped to the combination of dimension attributes that ...

  4. Hierarchical database model - Wikipedia

    en.wikipedia.org/wiki/Hierarchical_database_model

    If the "child" data type were different, it would be in a different table, but there would still be a foreign key referencing the EmpNo column of the employees table. This simple model is commonly known as the adjacency list model and was introduced by Dr. Edgar F. Codd after initial criticisms surfaced that the relational model could not model ...

  5. Dummy variable (statistics) - Wikipedia

    en.wikipedia.org/wiki/Dummy_variable_(statistics)

    In the panel data fixed effects estimator dummies are created for each of the units in cross-sectional data (e.g. firms or countries) or periods in a pooled time-series. However in such regressions either the constant term has to be removed, or one of the dummies removed making this the base category against which the others are assessed, for ...

  6. Sentinel value - Wikipedia

    en.wikipedia.org/wiki/Sentinel_value

    The sentinel value is a form of in-band data that makes it possible to detect the end of the data when no out-of-band data (such as an explicit size indication) is provided. The value should be selected in such a way that it is guaranteed to be distinct from all legal data values since otherwise, the presence of such values would prematurely ...

  7. Continuous or discrete variable - Wikipedia

    en.wikipedia.org/wiki/Continuous_or_discrete...

    A variable of this type is called a dummy variable. If the dependent variable is a dummy variable, then logistic regression or probit regression is commonly employed. In the case of regression analysis, a dummy variable can be used to represent subgroups of the sample in a study (e.g. the value 0 corresponding to a constituent of the control ...

  8. Industry standard data model - Wikipedia

    en.wikipedia.org/wiki/Industry_standard_data_model

    An industry standard data model, or simply standard data model, is a data model that is widely used in a particular industry. The use of standard data models makes the exchange of information easier and faster because it allows heterogeneous organizations to share an agreed vocabulary, semantics, format, and quality standard for data.

  9. Dimension (data warehouse) - Wikipedia

    en.wikipedia.org/wiki/Dimension_(data_warehouse)

    A common data warehouse example involves sales as the measure, with customer and product as dimensions. In each sale a customer buys a product. The data can be sliced by removing all customers except for a group under study, and then diced by grouping by product. A dimensional data element is similar to a categorical variable in statistics.