Best Practices for Data Modeling
with Ellie

Core elements of modeling with Ellie revolve around entities that form your Bussines Glossary, the word dictionary for the whole organization, and Conceptual Models, high level designs that capture a slice of reality and it's relationship with the data.

You can then use this knowledge to create an accurate technical implementation, by using Logical Models, and/or, sharing this metadata with other technical tools through Integrations and Ellie's open API.

Here are the key things to keep in mind!

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Conceptual Modeling Tips


How to identify entities?

The 4 Core Principles

#1: Entities are singular nouns
Not “Customers” but “Customer”; not “Condition Monitoring” but “Condition Measurement”

#2: Entities exist in the real world business
People, places, events, physical objects – not database tables, reports, or files

#3: Entities are countable
Always ask, “can I say I have x number of these?” and avoid abstractions like “Staff” or “Analytics”

#4: Attributes are not entities
“Customer name” is not an entity: it tells you something about the Customer, so it’s an attribute for that


Define entities as nouns, relationships as verbs

Find the story behind your model

A Data Model should always describe something in the real world that can also be described as a narrative: “A customer books an appointment in a bank office...”

Entities are usually the nouns of the story
Customer, Appointment, Bank

Relationships between entities are the verbs that describe the association
Customer books an appointment

Define your relationships with the correct verbs
Avoid meaningless words: “relates to”, “linked with”

Note that different verbs = different relationships
Customer books an appointment, but also customer cancels an appointment


Take advantage of entity types

Use colors to add extra meaning

• Ellie has predefined “entity types” that you can use

• You can also create custom entity types for your organization

• Shown as different colours of entities on the model canvas

• Use the entity types to make your model more easily readable

• Often they also help you figure out what’s missing: e.g. transactions can hardly exist by themselves, so who or what is doing something there?


Use subtypes and supertypes

Add layers to your entities

• Subtype-supertype structure is a very powerful pattern for modeling

• It allows you to define commonalities and distinctions between kinds of a thing

• Click and drag an entity inside another entity to “lock” them into a subtype structure


Create separate domain and use case models

It’s often wise to create two kinds of models in your Ellie

• Model an area of business or a process to understand core terminology and to get the big picture -> “domain model”

• Model the data need of a project or a use case, defining the scope about which you need data to accomplish your goals -> “use case model”

Remember that copying models is easy: use your domain models as the starting point of your use case models to make things easier!


Use collections to organize your models

Create Collections in Ellie’s Model List view to organize your models

A Collection is like a bucket for your models

A model can belong to any number of Collections

Useful ways to set up your Collections:
 1.  By business area (Consumer goods, Chemicals, Services...)
 2. By organizational unit (Sales, Finance, HR...)
 3. By model purpose (Enterprise-level domain models, DW-related  models...)

Logical Modeling tips:


Create Logical Models for implementation design

Technical implementation models

• Some use cases might work best with a specific model structure, such as a Dimensional Model - design these as Logical Models in Ellie!

• Keep the Conceptual Model as a model of your business scope

• Consider technical requirements and details such as key attributes in the Logical Mode


Link logical entities with the Ellie Glossary

Ensure continuous linkage between your logical models and business terms.

• Entities in a Logical Model can be linked with one or more Glossary items

• Use this to keep track of what your logical structures mean: “this table is about…

• For highly denormalized structures, consider listing all the Glossary items that your entity has data about - multiple links are possible!

• When using complex naming conventions for technical reasons, using Glossary links helps other people to understand what your model contains

Business Glossary tips:


Write understandable entity descriptions

Make sure to define your entities!

Entities in Ellie are reusable; if someone else later uses the entity you created, they need to know what it means

Aim for a short, clear definition in simple business language

Good pattern for entity description:
1.  Definition in max. 2 sentences
2. Some examples from real life to make it more concrete
3. Add examples of important special cases, if they exist.

Library customer

“A customer is an owner of a library card who can borrow books from our library. Customers are natural persons such as John Smith and Erin Example. A customer can also be an employee of the library. Underaged children who use their parents’ cards are not considered separate customers."


Check how entities are being used across models

Explore the big picture of your entity relationships

• You will find a lot of information from the Relationships tab when viewing an entity

• All models in which the entity is used are listed here

•Ellie also automatically lists all relationships that the entity has to other entities across all models

• Use this view to find out what others have done with the same entity, and what you could possibly reuse in your own model


Avoid technical names

Remember that it’s a Business Glossary!

• Avoid technical names, use terms like Customer, Sales Order etc., and avoid technicals terms such as CSD_0123, BSEG, BKPF, etc.

• Your entities should be real-life things from the business, not technical objects

• Avoid naming your entities after database tables or using system-specific terminology



Forward-engineering workflow

Use Ellie knowledge with other tools

• Capture business requirements & scope in Ellie

• Export models from Ellie and import them to technical data engineering tools to create/generate physical models and structures

• Use Ellie’s Model Export API or file-based exports to catch model metadata from Ellie

• Consider tools such as WhereScape, VaultSpeed, or Datavault Builder, which have their own integrations with Ellie built in!


Synchronize Ellie’s Glossary with external sources

Maintain your context across the tools

• Use Ellie’s Glossary API endpoints to read information from Ellie’s Glossary - even for individual entities

• Write back information such as technical implementation details to make it easily accessible from Ellie API Documentation

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