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  2. Candidate key - Wikipedia

    en.wikipedia.org/wiki/Candidate_key

    The columns in a candidate key are called prime attributes, [3] and a column that does not occur in any candidate key is called a non-prime attribute. Every relation without NULL values will have at least one candidate key: Since there cannot be duplicate rows, the set of all columns is a superkey, and if that isn't minimal, some subset of that ...

  3. Database normalization - Wikipedia

    en.wikipedia.org/wiki/Database_normalization

    To conform to 2NF and remove duplicates, every non-candidate-key attribute must depend on the whole candidate key, not just part of it. To normalize this table, make {Title} a (simple) candidate key (the primary key) so that every non-candidate-key attribute depends on the whole candidate key, and remove Price into a separate table so that its ...

  4. Composite key - Wikipedia

    en.wikipedia.org/wiki/Composite_key

    In database design, a composite key is a candidate key that consists of two or more attributes, [1] [2] [3] (table columns) that together uniquely identify an entity occurrence (table row). A compound key is a composite key for which each attribute that makes up the key is a foreign key in its own right.

  5. Foreign key - Wikipedia

    en.wikipedia.org/wiki/Foreign_key

    A foreign key is a set of attributes in a table that refers to the primary key of another table, linking these two tables. In the context of relational databases, a foreign key is subject to an inclusion dependency constraint that the tuples consisting of the foreign key attributes in one relation, R, must also exist in some other (not necessarily distinct) relation, S; furthermore that those ...

  6. Second normal form - Wikipedia

    en.wikipedia.org/wiki/Second_normal_form

    There is a multi-attribute unique identifier/candidate key: "Manufacturer" and "Model". {Manufacturer country} is functionally dependent (predictable) on {Manufacturer}. {Manufacturer} is a proper subset of the {Manufacturer, Model} candidate key. {Manufacturer country} is not part of a candidate key, so it is a non-prime attribute.

  7. How tall is Donald Trump? What's Kamala Harris' racial ... - AOL

    www.aol.com/tall-donald-trump-whats-kamala...

    Presidential candidate Kamala Harris and Donald Trump will go head to head for the first time in a debate Tuesday night where Americans will hear each candidate's views on various topics and policies.

  8. Unique key - Wikipedia

    en.wikipedia.org/wiki/Unique_key

    In relational database management systems, a unique key is a candidate key. All the candidate keys of a relation can uniquely identify the records of the relation, but only one of them is used as the primary key of the relation. The remaining candidate keys are called unique keys because they can uniquely identify a record in a relation.

  9. 'Landman' Star Billy Bob Thornton Makes Rare Appearance With ...

    www.aol.com/landman-star-billy-bob-thornton...

    Last night, he attended the Paramount Golden Globe Nominee Celebration at Cipriani Beverly Hills.