| A | B |
|---|
| primary key | a column or a set of columns that uniquely identifies each row in a table |
| candidate key | a column or a combination of columns that could serve as a tables primary key |
| foriegn key | a column or a combination of columns that refers to a primary key in the same table or another table |
| data integrity (constraints) | define the relationally correct state for a database and is used to ensure that users can perfrom only those operations that leave the database in a correct, consistent state |
| entity integrity | a primary key must be unique, and no part of the primary key can be null |
| referential integrity | a foriegn key must match an existing primary key value (or else be null) |
| column integrity | a column must contain only values consistent with the defined data format of the column |
| user defined integrity | the data stored in a database must comply with the erules of the business |
| relational database | collection of objects or relations, set of operators to act on those relations, and data integrity for accuracy and consistency |
| row | a entry in a table consisting of values for each appropriate column |
| column | an implementation of an attribute or relationship in a table |
