engineering

Structured entity relationship model

Structured entity relationship model is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Structured entity relationship model rather than just read about it. In short: The SERM (structured entity relationship model) is an extension of the ERM that is commonly used for data modeling. It was first proposed by Prof.

Key takeaways

Structured entity relationship model belongs to engineering; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Structured entity relationship model to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Structured entity relationship model from memory before moving on to harder problems.

Reference excerpt

The SERM (structured entity relationship model) is an extension of the ERM that is commonly used for data modeling. It was first proposed by Prof. Dr. Elmar J. Sinz in 1988. The SERM is commonly used in the SAP world for data modeling.

Aims structuring of large schemes visualization of existence dependency avoidance of inconsistencies avoidance of unnecessary relationship types

SERM symbols

SERM example

The entities customer and article are independent. Every order relates to exactly one customer. Orders without customers are illegal. Customers without any orders are legal, because they are independent entities. Every order relates to at least one order item. Every order item relates to exactly one order. Every invoice relates to exactly one customer. Invoices without customers are illegal. Customers without any invoice are legal. Every invoice relates to at least one invoice line item. Every invoice line item relates to exactly one order item. This example, like any valid SERM scheme, is already in the third normal form.

References

Illustrations

Structured entity relationship model illustration

Worked examples

Example 1 — a first encounter with Structured entity relationship model

Start with the simplest possible case. Write down what Structured entity relationship model claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Structured entity relationship model before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Structured entity relationship model ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Structured entity relationship model

In research: Structured entity relationship model appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Structured entity relationship model in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Structured entity relationship model is common in secondary-school and first-year university syllabi. It links to neighbouring topics Data modeling, Diagrams, Modeling languages, so understanding it makes those chapters shorter.
In everyday life: Look for Structured entity relationship model outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Structured entity relationship model in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Structured entity relationship model means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Structured entity relationship model out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Structured entity relationship model in simple terms?

The SERM (structured entity relationship model) is an extension of the ERM that is commonly used for data modeling. It was first proposed by Prof.

Why does Structured entity relationship model matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Structured entity relationship model?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Structured entity relationship model.