How to Read the Conceptual Diagram

This page explains how to understand the conceptual ER diagram of the data model.

The diagram shows:

the main types of things we describe (boxes)
and how they are connected (lines)

It is only a visual guide.

No technical knowledge is required.

Boxes

Each box represents one type of thing in our research.

Examples:

HeritageObject
Person
Organization
Place
DigitalAsset
ResearchChapter

Think of a box simply as:

a category of information

Lines

Lines show relationships between boxes.

They answer questions like:

Who is connected to what?
Which source documents which object?
Where is something located?

A line means:

these two things are related

One and many

Some relations are:

one-to-one
one-to-many
many-to-many

Instead of technical words, we use simple language.

One-to-many

One item can be linked to several others.

Example:

one Place → many DigitalAssets
one HeritageObject → many DigitalAssets
one ResearchChapter → many HeritageObjects

Meaning:

One thing can have multiple related items.

Many-to-one

The same relation seen from the other side.

Example:

many DigitalAssets → one Place

Meaning:

Several sources can describe the same place.

Many-to-many

Both sides can have several connections.

Example:

many Persons ↔ many HeritageObjects
many Organizations ↔ many HeritageObjects

Meaning:

A person can be involved in several objects, and each object can involve several persons.

Meaning of the main relations

Below are the most important relations in the diagram, expressed in everyday language.

HeritageObject — DigitalAsset

"documented by"

A HeritageObject can be documented by many DigitalAssets.

Person — HeritageObject

"involved in"

Persons are linked with a role (architect, director, teacher, etc.).

Organization — HeritageObject

"responsible for"

Organizations may own, manage, or operate objects.

Place — HeritageObject

"located at"

Objects exist somewhere geographically.

Place — DigitalAsset

"describes"

Sources may directly document a place (map, postcard, photo).

ResearchChapter — HeritageObject

"discussed in"

Chapters group objects into parts of the story.

Symbols used in the diagram

Some diagrams use small symbols at the ends of lines to show “one” or “many”.

The exact drawing may vary slightly, but the meaning is always the same.

Symbol	Meaning	Example
(single line)	one	one Place
< or crow’s foot	many	many DigitalAssets
—<	one-to-many	one Place → many DigitalAssets
>—<	many-to-many	many Persons ↔ many HeritageObjects
—\|	one-to-one	one item linked to exactly one other

Important note

The diagram is conceptual.

It explains meaning only.

It does not show technical database details.

In one sentence

Boxes show types of things. Lines show how those things are connected. Symbols show whether there is one or many.