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

About

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.

Monitoring

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.

You can find duplicate records with the use of an Cryptography - Hash

The entity integrity is a data quality metrics.