Data models are visual representations of components that are important to the business which includes its people, places, things, and business transactions and their relationships.
They are used in numerous business analysis such as elicitation, requirements analysis and design, support implementation and continuous improvement.
There are many forms of data models, which include:
- Conceptual data model: this is used to show how the organization views its information. It can be used to help set up a standardized terminology describing the business information and the relationships between that information.
- Logical data model: this includes rules to maintain the integrity of the data and its relationships. It is usually connected to the design of a solution.
- Physical data model: this is used to define how a database is physically organized. It prevents problems associated with performance, concurrency, and security.
There are some elements of data models which are:
1. Entity or Class: An entity could represent a tangible asset such as a building, a cost center such as marketing or a particular service being offered by the organization.
In the context of class diagram, entities are called classes, which has functions that define its capabilities such as creating a new customer account.
2. Attribute: An attribute is some information about an entity, such as name, description and its allowable values. They can be defined in a data dictionary and specified through business rules.
3. Relationship or Association: Entities are related to one another in a data model. Details of these relationships are defined so that they are properly understood.
These details include the cardinality which is the minimum and maximum number of occurrences to which an entity may be related. The cardinality values may be zero, one, and many. for example, every employee is related to one cost center area, but a cost center may be related to zero, one, or many employees.
4. Diagrams: Diagrams can be used to show entities, attributes, and relationships in both the data and class models.
These diagrams are known as an entity-relationship diagram (ERD) in data models while in class model, they are called a class diagram.
5. Metadata: Metadata describes important information about the data models such as when the entities were created.
Data models has both its strengths and limitations, which include:
Strengths
- It can be used to describe standardized terminologies used by both domain subject matter experts and implementation subject matter experts.
- It ensures that the logical design accurately represents what the business need.
- It gives a consistent approach to analyzing and documenting data and its relationships.
- It may expose new requirements or inconsistencies.
Limitations
- It may be too technical for the stakeholders.
- It may be quite complex and difficult for the stakeholders to understand.