| Term | Definition |
|---|
| relational model | uses a N-ary relation between attribute sets to model entity set |
| relation instance | a table with a column for each attribute which is atomic; each row represents an entity |
| relation schema | relation name followed by a parenthesized list of attribute names with associated domains followed by constraints |
| database schema | collection of relation schemas |
| type constraint | value in column must be of corresponding data type |
| data atomicity | single value in each column |
| key constraint | any relation or table has at most one row for some combination of values of key attributes |
| foreign key | an attribute of a relation which serves as a primary key of another relation |
| candidate key | a minimal set of attributes which is a key |
| superkey | any key including a set of all attributes of a relation |
| functional dependency | a set of attributes x which uniquely determines a set of Y attributes |
| determinant | left side of a functional dependency |
| anomaly | an error or inconsistency due to redundant data resulting from insertion, update or deletion |
| binary relation | a relation between two entity sets |
| cardinality constraint | a bound on the number of times an instance of an entity can be related to an instance of another entity |
| composite key | a key consisting of more than one attribute |
| relational database | a database consisting of relations (tables) |
| 1st normal form | every attribute is atomic |
| partial dependency | a functional dependency in which non-key attributes are functionally dependent on part but not all of the primary key attributes |
| 2nd normal form | no partial dependencies |
| transitive dependency | an attribute that does not depend on the key of the table |
| 3rd Normal form | no transitive dependencies |
| Boyce Codd Normal Form | a relation in which every determinant is a candidate key |
| foreign key constraint | there is a tuple or row of the primary key table with same value as value of foreign key |
Combine with other sets
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