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  2. Cardinality (data modeling) - Wikipedia

    en.wikipedia.org/wiki/Cardinality_(data_modeling)

    For example, consider a database of electronic health records. Such a database could contain tables like the following: A doctor table with information about physicians. A patient table for medical subjects undergoing treatment. An appointment table with an entry for each hospital visit. Natural relationships exist between these entities:

  3. Clinical Document Architecture - Wikipedia

    en.wikipedia.org/wiki/Clinical_Document_Architecture

    CDA can hold any kind of clinical information that would be included in a patient's medical record; examples include: [1] Discharge summary (following inpatient care) History & physical; Specialist reports, such as those for medical imaging or pathology

  4. Cardinality (SQL statements) - Wikipedia

    en.wikipedia.org/wiki/Cardinality_(SQL_statements)

    High-cardinality refers to columns with values that are very uncommon or unique. High-cardinality column values are typically identification numbers, email addresses, or user names. An example of a data table column with high-cardinality would be a USERS table with a column named USER_ID. This column would contain unique values of 1-n. Each ...

  5. One-to-many (data model) - Wikipedia

    en.wikipedia.org/wiki/One-to-many_(data_model)

    In systems analysis, a one-to-many relationship is a type of cardinality that refers to the relationship between two entities (see also entity–relationship model). For example, take a car and an owner of the car. The car can only be owned by one owner at a time or not owned at all, and an owner could own zero, one, or multiple cars.

  6. Count-distinct problem - Wikipedia

    en.wikipedia.org/wiki/Count-distinct_problem

    In computer science, the count-distinct problem [1] (also known in applied mathematics as the cardinality estimation problem) is the problem of finding the number of distinct elements in a data stream with repeated elements. This is a well-known problem with numerous applications.

  7. Cardinality - Wikipedia

    en.wikipedia.org/wiki/Cardinality

    The picture shows an example f and the corresponding T; red: n∈f(n)\T, blue:n∈T\f(n). While the cardinality of a finite set is simply comparable to its number of elements, extending the notion to infinite sets usually starts with defining the notion of comparison of arbitrary sets (some of which are possibly infinite).

  8. Bitmap index - Wikipedia

    en.wikipedia.org/wiki/Bitmap_index

    A bitmap index is a special kind of database index that uses bitmaps.. Bitmap indexes have traditionally been considered to work well for low-cardinality columns, which have a modest number of distinct values, either absolutely, or relative to the number of records that contain the data.

  9. One-to-one (data model) - Wikipedia

    en.wikipedia.org/wiki/One-to-one_(data_model)

    A country has only one capital city, and a capital city is the capital of only one country. (Not valid for some countries).. In systems analysis, a one-to-one relationship is a type of cardinality that refers to the relationship between two entities (see also entity–relationship model) A and B in which one element of A may only be linked to one element of B, and vice versa.