Conceptual data model is a map of key concepts and rules binding these key concepts for a specific business, for a particular audience, that used for databases. Key concepts are both basic and critical to your business. Basic means this term is mentioned many times a day in your organisation in conversation among business people, such as CUSTOMER, EMPLOYEE, PRODUCT, etc.Critical means the business would be very different or non-existent without this key concept. For example, without the concept PRODUCT, your business may become non-existent.
Keys in data modeling
December 26, 2015 / by Rathish Kumar B
In data modeling, we use keys for data retrieval and easy navigation. In this post we are going to discuss about the different keys used in data modeling such as candidate keys, composite keys, primary keys, alternate keys, surrogate keys and foreign keys and their important.
Relationships and Cardinality
December 24, 2015 / by Rathish Kumar B
In real world, entities have relationships with other entities. Relationships define how two entities are associated with each other. The data modeling captures the nature of relationship between two entities. For example, the entity 'Customer' buys the 'Product' and the entity 'Vendor' sells the 'Product'. It captures the rules between these two entities. If two entities are Person and Telephone Number, the relationship may capture the rule "Each Person may have many Telephone Numbers" and "Each Telephone Number must belongs to one Person."
Data fields and domains
December 21, 2015 / by Rathish Kumar B
In previous post we have seen about the entities, in this post let us see about the data fields and domains. Data field is nothing but a column header or label describing instances of an entity. The data field Customer Name describes name of each Customer. The data field Model Number identifies each model.
Entities
December 18, 2015 / by Rathish Kumar B
An entity represents a collection of information about something that the business deems important and worthy of capture. A noun identifies a specific entity. Usually an entity fits into one of several categories - who, what, when, where, why, or how.
Levels of a data model
December 17, 2015 / by Rathish Kumar B
There are three different levels of Data Model, this makes the model either at a very broad and high level conceptual view, or a more detailed logical or physical view.
The levels of different models are given below,
- Conceptual data model (CDM) or Subject area model (SAM).
- Logical data model (LDM).
- Physical Data Model (PDM).
Uses of data model
December 16, 2015 / by Rathish Kumar B
Traditionally, data models are created to ensure that the requirements for a new applications are fully understood and correctly captured before the actual database is created. Usually data models are created during the analysis and designing phases of a project.
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