A real world problem usually contains groups of entity types that are similar. For example, consider a company that has hundreds of customers. All of the customers are entities. These customer entities share the same properties, but each entity will have its own values for the properties. Such similar entities define an entity type, which is a set of entities with the same properties.
ER Models and C/SIDE
When you implement the abstract ER model in C/SIDE, you transform all the abstract elements in your model into concrete representations. Each entity type corresponds to a table in C/SIDE and each of the entity’s properties corresponds to a field in the table.
The following table summarizes how basic ER model concepts relate to C/SIDE concepts.
| ER model concept | Corresponding concept in C/SIDE |
|---|---|
|
An entity type |
A table |
|
An entity |
A record |
|
A property |
A field |