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Definition
| collection of organized data |
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Term
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Definition
| Database Management System |
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| Database Management System? |
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Definition
| collection of programs that manage database structure and data |
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Definition
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Definition
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Definition
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Definition
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Definition
| collection of related rows |
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Definition
| file dependent on structure |
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Term
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Definition
| data characteristics dependent on structure |
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Definition
| same data different in another location |
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Definition
| data not updated in both locations |
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Definition
| can't add information to one thing because you don't have other information |
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Term
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Definition
| referencing something that doesn't' exist |
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Term
| Data blocks for data modeling |
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Definition
| entity, relationship, attribute, constraint |
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Definition
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Definition
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Definition
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Term
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Definition
| brief and precise description of a policy |
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Term
| data abstraction levels in data modeling: |
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Definition
Highest = External, end user
Conceptual, designer
internal, tables |
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Term
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Definition
| change of the internal model without effecting the conceptual model (change int to string) |
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Term
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Definition
| change in physical model without effecting internal model (change algorithms) |
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Term
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Definition
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Term
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Definition
| unique key in one table referencing a table it's a primary key in |
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Term
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Definition
| any key that uniquely identifies each row |
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Term
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Definition
| a super key without unnecessary attributes |
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Term
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Definition
| composed of more than one atrribute |
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Term
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Definition
| value must be unique and must not be null |
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Term
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Definition
| if value of foreign key is not null, then the value must exist in the table it references |
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Term
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Definition
| selects a group of rows that satisfy the condition |
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Term
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Definition
| selects distinct attributes fro a table |
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Term
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Definition
combines rows from two tables
(union-compatible) |
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Term
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Definition
includes all rows that are in both tables
(union-compatible) |
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Term
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Definition
includes all rows that are in the first table, but not the second
(union-compatible) |
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Term
| PRODUCT (CARTESIAN PRODUCT) |
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Definition
| includes all possible pairs |
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Term
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Definition
| combines related rows from two tables into single table |
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Term
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Definition
| only returns matched rows being joined |
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Term
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Definition
| matched pairs will be retained, any unmatched values in the other table will be left null |
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Term
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Definition
| keeps everything in left table |
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Term
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Definition
| keeps everything in right table |
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Definition
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Term
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Definition
| result of a single attribute table with the values of attribute "a" from the dividend relation rows where the value of "b" in both relations |
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Term
| 2 conditions that must be met before an entity can be classified as weak |
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Definition
| existent dependent and the PK must be derived or partially derived from an entity |
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Term
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Definition
| a relationship only related to ssingle |
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Term
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Definition
| entity whose attribte can be derived |
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Term
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Definition
| bridges a (m:n) relationship |
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