| Term | Definition |
|---|
| Can't be broken down | Simple Atomic Attribute |
| Can be broken down | Composite Attribute |
| Can take on one value for a given entity instance | Single Valued Attribute |
| May take on more than one value for a given entity instance | Multi Valued Attribute |
| Can be calculated from related attribute values | Derived Attribute |
| An attribute that uniquely identifies a record | Primary key |
| A primary key that consists of a combination of attributes | Composite key |
| An attribute in one table that matches the primary key of another table | Foreign key |
| An attribute or combination of attributes that could have served as a primary key, but was not selected to be the primary key | Candidate key |
| A table identifier that is created by the data modeler | Surrogate key |
| When all of the rows of a database table are uniquely identified | Entity integrity |
| When all the foreign keys in one table either match the primary key values in the related table or are null (empty) | Referential integrity |
| A meaningful association between entity types | Relationship |
| One record | Entity instance |
| Whole table | Entity type |
| A record in one entity is related to a maximum of one record in another entity | 1:1 |
| A record in one entity is related to a maximum of many records in another entity | 1:M |
| Individual records on each side of a relationship can be related to many records on the other side of the relationship | M:N |
| The number of entity types that participate in a relationship | Degree |
| A relationship between the instances of a single entity type | Unary (or reflexive) |
| A relationship between the instances of two entity types | Binary |
| A simultaneous relationship among the instances of many entity types | Ternary |
| The relationship between a weak entity type and its owner is called | Identifying relationship |
Combine with other sets
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