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  2. Snowflake schema - Wikipedia

    en.wikipedia.org/wiki/Snowflake_schema

    The snowflake schema is represented by centralized fact tables which are connected to multiple dimensions. "Snowflaking" is a method of normalizing the dimension tables in a star schema. When it is completely normalized along all the dimension tables, the resultant structure resembles a snowflake with the fact table in the middle. The principle ...

  3. Help:Introduction to tables with Wiki Markup/3 - Wikipedia

    en.wikipedia.org/wiki/Help:Introduction_to...

    To add an extra row into a table, you'll need to insert an extra row break and the same number of new cells as are in the other rows. The easiest way to do this in practice, is to duplicate an existing row by copying and pasting the markup. It's then just a matter of editing the cell contents.

  4. Early-arriving fact - Wikipedia

    en.wikipedia.org/wiki/Early-arriving_fact

    In the data warehouse practice of extract, transform, load (ETL), an early fact or early-arriving fact, [1] also known as late-arriving dimension or late-arriving data, [2] denotes the detection of a dimensional natural key during fact table source loading, prior to the assignment of a corresponding primary key or surrogate key in the dimension table.

  5. Relational database - Wikipedia

    en.wikipedia.org/wiki/Relational_database

    Each row in a table has its own unique key. Rows in a table can be linked to rows in other tables by adding a column for the unique key of the linked row (such columns are known as foreign keys). Codd showed that data relationships of arbitrary complexity can be represented by a simple set of concepts. [2]

  6. Extract, transform, load - Wikipedia

    en.wikipedia.org/wiki/Extract,_transform,_load

    Splitting a column into multiple columns (e.g., converting a comma-separated list, specified as a string in one column, into individual values in different columns) Disaggregating repeating columns; Looking up and validating the relevant data from tables or referential files

  7. Dimension (data warehouse) - Wikipedia

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

    Type 3 (Add new attribute): A new column is created for a new value. History is limited to the number of columns designated for storing historical data. Type 4 (Add history table): One table keeps the current value, while the history is saved in a second table. Type 5 (Combined Approach 1 + 4): Combination of type 1 and type 4. History is ...

  8. Online analytical processing - Wikipedia

    en.wikipedia.org/wiki/Online_analytical_processing

    The cube metadata is typically created from a star schema or snowflake schema or fact constellation of tables in a relational database. Measures are derived from the records in the fact table and dimensions are derived from the dimension tables. Each measure can be thought of as having a set of labels, or meta-data associated with it.

  9. Fact table - Wikipedia

    en.wikipedia.org/wiki/Fact_table

    It is located at the center of a star schema or a snowflake schema surrounded by dimension tables. Where multiple fact tables are used, these are arranged as a fact constellation schema. A fact table typically has two types of columns: those that contain facts and those that are a foreign key to dimension tables. The primary key of a fact table ...