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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 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
|
 |
| Primary Key |
 |
|