Database Reference
In-Depth Information
These are, of course, generic guidelines that will need to be tried and tested on every
domainindividuallytomakesurethatitisanappropriateit.However,fornow,
let's look at the following diagram:
An Entity-Relationship diagram
Asyoucanseefromtheprecedingigure,ERdiagramshavetheadvantageofat
least attempting to capture the business domain in a real-world model. However,
they suffer from quite a few disadvantages too. Despite being visually very similar
to graph visualizations, ER diagrams immediately demonstrate the shortcomings of
the relational model to capture a rich domain. Although they allow relationships to
be named (something that graph databases fully embrace, but relational stores do
not),ERdiagramsallowonlysingle,undirected,namedbutotherwiseunqualiied
relationshipsbetweenentities.Inthisrespect,therelationalmodelisapooritfor
real-world domains where relationships between entities are numerous, semantically
rich, and diverse. The labeled property graph, as we have seen previously,
allowsforamuchricherdescriptionofthedomain,speciicallywithregardto
the relationships between the entities—which will be multiple, directed, and
qualiiedthroughproperties.
The problem of relational ER modeling becomes even worse when we take the
ER diagram to an actual system and are faced with serious limitations. Let's take
a look at how one of the relational model's fundamental problems becomes
apparent when we take the diagram to a test in a real-world implementation.
