Logical Data Modeling - Primary Key (Id, Name)

About

A Primary Key is a key that identify indefinitely uniquely an element:

A real primary key is immutable as it should identify the entity for ever.

Note that if the data is:

the data will change in some time and are not truly good candidate for a real primary key.

That's why the primary key should be generated (surrogate key)

The less, the beter has a primary key is used everywhere:

Generally a primary key is stored via a traditional 4-byte index value.

A numeric primary key is called an id

A textual primary key is called a name

A entity key is a key that:

identify uniquely a single entity
doesn't change over time. If the primary key has a chance – however remote – of changing, well, then it is NOT the primary key.
define, in dimensional modeling, the lowest level of an entity

This is one or a group of attributes such that the relationship between the entity set and the attribute value sets has a one-to-one cardinality.

There are two fundamental types of primary keys:

Relational database: Relational Data Modeling - Primary key
Code: map where the key is the primary key (other implementation may be possible)