Logical Data Modeling - Entity Integrity (Uniqueness|No Duplicate|Distinct)

Entity integrity concerns the concept of uniqueness (also called no duplicate)

Uniqueness is enforced with:

• primary key
• unique key (on a column or indice)

Entity integrity is an integrity rule which states that every table must have a primary key and that the column or columns chosen to be the primary key should be unique and not null.

Asserting uniqueness of the entities within a data set implies that no:

• entity
• or relation between entity

exists more than once within the data set.

This attribute can be monitored two ways :

• As a static assessment, it implies applying duplicate analysis to the data set to determine if duplicate records exist
• As an ongoing monitoring process, it implies providing an identity matching and resolution service at the time of record creation to locate exact or potential matching records.

The entity integrity is a data quality metrics.