DTM Data Modeler uses basic elements of IDEF1X notation. IDEF1X is a method for designing relational databases.
There are two basic elements of model: entity and relationship. In IDEF1X notation, entities are either independent (also known as parent or master) or dependent (also known as child or detail).
Also, relationships are either identifying or non-identifying.

Any entity must contain one or more attributes. Attributes are properties used to describe an entity. Any attribute must have name and type (data type like integer or char).

A key is a set of attributes that uniquely identify an entity instance. DTM Data Modeler supports primary keys only and every entity has only one primary key. The attributes of the primary key displayed above the horizontal line in the entity box.

The following table describes method elements that can be used with DTM Data Modeler:

Model element	Visual representation
Independent Entity
Dependent Entity
Identifying relationship
Non-identifying relationship, NULL does not allowed
Non-identifying relationship, NULL is allowed
Primary Key