CODEWITHSUNDEEP
database
Smple_V
Smple_V

Reputation: 868

Difference between Data models

Need a brief difference between network model, relational model,entity set model like why and when can each one be used?

I have looked into various resources but there needs to be a brief and concise idea about the said topic

Upvotes: 0

Views: 359

Answers (2)

reaanb
reaanb

Reputation: 10065

In graph terms, the relational model is an undirected n-ary graph in which the nodes are values and the edges are rows. Logically, tables represent predicates and rows represent propositions about entities which are represented as values of a domain. Edges are joined to form paths and processed in sets.

The entity-relationship model is also an undirected n-ary graph in which some tables represent sets of nodes and other tables represent sets of edges. It's a "semantic framework" built on top of the relational model, and while it offers a seemingly simpler and richer structure than the pure relational model, it's actually more complicated and less expressive. It's usually queried and processed using relational mechanisms.

The network data model is a directed binary graph in which the nodes are rows and the edges are pointers. Unlike relational models it's usually processed imperatively and edges are navigated to get to related nodes. It makes a hard distinction between attributes and relationships (unlike ER in which attributes are binary relationships).

I'm not very familiar with the entity set model and haven't seen it in the field. Did you perhaps mean the entity-relationship model? For more on the entity set model, see Data structures and accessing in data-base systems.

Different data models exist since people have different concepts of how best to organize, manipulate and access data. The relational model is the only one that has been proven equivalent to first-order logic. While knowledge of these models are invaluable in understanding data, we don't get to choose models freely, but must choose among software systems that tend to implement a mish-mash of models and features.

Upvotes: 1

janos97
janos97

Reputation: 51

A quick google search shows some pretty decent explanations.

If this is not what you're asking, please clarify the question.

Upvotes: 0

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