When.com Web Search

Search results

1. Results From The WOW.Com Content Network

2. Candidate key - Wikipedia

   en.wikipedia.org/wiki/Candidate_key

   A candidate key, or simply a key, ... Keys: An overview of the different types of keys in the RDBMS (Relational Database Management System). ...

3. Superkey - Wikipedia

   en.wikipedia.org/wiki/Superkey

   A candidate key (or minimal superkey) is a superkey that can't be reduced to a simpler superkey by removing an attribute. [ 3 ] For example, in an employee schema with attributes employeeID , name , job , and departmentID , if employeeID values are unique then employeeID combined with any or all of the other attributes can uniquely identify ...

4. 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.

5. 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 ...

6. Relational model - Wikipedia

   en.wikipedia.org/wiki/Relational_model

   Usually one candidate key is chosen to be called the primary key and used in preference over the other candidate keys, which are then called alternate keys. A candidate key is a unique identifier enforcing that no tuple will be duplicated; this would make the relation into something else, namely a bag, by violating the basic definition of a set ...

7. Third normal form - Wikipedia

   en.wikipedia.org/wiki/Third_normal_form

   A database relation (e.g. a database table) is said to meet third normal form standards if all the attributes (e.g. database columns) are functionally dependent on solely a key, except the case of functional dependency whose right hand side is a prime attribute (an attribute which is strictly included into some key).