Term
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Definition
| a named two-dimensional table of data |
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Term
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Definition
| an attribute or combination of attributes that uniquely identifies each row in a relation |
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Term
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Definition
| a primary key that consists of more than one attribute |
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Term
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Definition
| an attribute in a relation that serves as the primary key of another relation in the same database |
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Term
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Definition
| a value that may be assigned to an attribute when no other value applies or when the applicable value is unknown |
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Term
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Definition
| a rule that states that no primary key attribute (or component of a primary key attribute) may be null |
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Term
| referential integrity rule |
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Definition
| a rule that states that either each foreign key value must match a primary key value in another relation or the foreign key value must be null |
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Term
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Definition
| a relation that contains minimal redundancy and allows users to insert, modify, and delete the rows in a table without errors or inconsistencies |
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Term
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Definition
| an error or inconsistency that may result when a user attempts to update a table that contains redundant data (three types: insertion, deletion, modification) |
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Term
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Definition
| a serial number or other system-assigned primary key for a relation |
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Term
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Definition
| a foreign key in a relation that references the primary key values of the same relation |
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Term
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Definition
| the process of decomposing relations with anomalies to produce smaller, well structured relations |
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Term
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Definition
| a state of a relation that requires that certain rules regarding relationships between attributes (or functional dependencies) are satisfied |
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Term
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Definition
| a constraint between two attributes in which the value of one attribute is determined by the value of another attribute |
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Term
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Definition
| the attribute on the left side of the arrow in the functional dependency |
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Term
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Definition
| an attribute, or combination of attributes, that uniquely identifies a row in a relation |
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Term
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Definition
| a relation that has a primary key and in which there are no repeating groups |
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Term
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Definition
| a relation in first normal form in which every nonkey attribute is fully functionally dependent on the primary key |
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Term
| partial functional dependency |
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Definition
| a functional dependency in which one or more nonkey attributes are functionally dependent on part (but not all) of the primary key |
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Term
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Definition
| a relation that is in second normal form and has no transitive dependencies |
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Term
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Definition
| a functional dependency between a primary key and one or more nonkey attributes that are dependent on the primary key via another nonkey attribute |
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Term
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Definition
| an alternative name used for an attribute |
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Term
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Definition
| an attribute that may have more than one meaning |
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Term
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Definition
| two (or more) attributes that have different names but the same meaning |
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Term
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Definition
| a primary key whose value is unique across all relations |
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