Crow’s foot notation in ER diagram

Use crows foot notation to represent relationships between entities in an entity relational diagram. Entities are connected by lines, and symbols at the beginning or end of the line describe cardinality.

Relationship types and cardinality:

Symbols in crow’s foot notation

A crow’s foot graphics represents “many” or “infinite”.… Read the rest

MongoDB ER diagram graphics

Settings for MongoDB ER diagram graphics can be defined on two levels in Moon Modeler. On a project level and on a selected object level.

Project graphics

Click the MongoDB ER diagram area to make sure no object is selected. Then change the colors in section Graphics. Alternatively, edit Project properties and specify settings on tab Graphics of the modal form.… Read the rest

What is Entity Relationship Diagram (ERD)?

Entity relationship diagram describes the structure of the database. The entity relationship diagram shows entities (tables in relational databases) and relationships between tables that exist in the database. For a good database design, it is very important to have an entity relationship diagram.

In an entity relationship diagram, the basic elements are:

  • Entities (tables)
  • Attributes (table columns)
  • Relationships (relationships between tables)

Why create entity relational diagrams?

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Custom data types

Moon Modeler allows you to define custom data types. If you need to use newly introduced data types, define them in the project settings. Then use these data types in your diagrams.

How to define custom data types?

You can add new data types to your project visually. (Similar to defining TAGs in various web applications).… Read the rest

Forward engineering

When it comes to forward engineering in Moon Modeler, it’s about generating the resulting script for the selected target platform.

In the case of relational databases such as PostgreSQL, MariaDB, MySQL or SQLite, it is the resulting SQL script. For MongoDB it is possible to generate a schema validation script and for platforms like Mongoose or GraphQL it is schema definition scripts.… Read the rest

Reverse engineering

Reverse engineering means retrieving information about the database structure. It is about finding out what objects exist in the database, such as tables, columns, views, procedures, etc., and what relationships exist between these objects. Based on this information, it is possible to draw an ER diagram in which the relationships can be clearly displayed.… Read the rest

Projects in Moon Modeler

You can save your database structures and schema designs in Moon Modeler into projects.

On the project overview page, you can search projects by name or platform, quickly find the platform for which the project was created, and also view examples on a separate tab.

Projects created in Moon Modeler.

What does the Project contain?

  • List of all objects that exist in the structure
  • Main diagram, in which certain objects can be shown or hidden
  • Additional subdiagrams that are used to visualize a specific group of objects

Creating projects

  • You can create a completely new project and start creating a database design or schema design from scratch
  • It is also possible to load an existing project from a file or from a URL.
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Free ER diagram tool?

Looking for a free ER diagram tool? There are many on the market and Moon Modeler is one of them.
This free ER diagram tool can be used to visually define smaller database structures for relational database systems such as MariaDB, MySQL, PostgreSQL, SQLite, and NoSQL databases such as MongoDB, or object-document mappers such as Mongoose.… Read the rest