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

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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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

Import & Visualization of existing SQLite databases

Connection to SQLite database is not classic, so you will not find the option of this database in the connections section. To visualize an existing SQLite database structure, go to the Projects section and import SQLite from a file.

Import file - SQLite

Select the database file. In this example, we will load the chinook.db… Read the rest

SQLite database design

Quick start guide for SQLite database design in Moon Modeler.

  1. New project
  2. Tables and columns
  3. JSON datatypes
  4. Relations and foreign keys
  5. Code generation

1. New project

To create a new project, click New on the toolbar and select the MariaDB project type.

2. Database tables and columns

New database tables can be inserted into projects by clicking Table on the toolbar and then by clicking the main diagram area.… Read the rest

Visualization of existing MySQL databases

All database connections are available in the Connections section. To create a new connection, click the Connections button on the main toolbar, and then click Create New Connection. A new modal form opens. Select MySQL and enter the connection details.

When you are finished, click the Save Connection button.

Database connections

Your new MySQL connection will appear in the list of all database connections.… Read the rest

MySQL database modeling

In Moon Modeler you can easily draw MySQL structures.

Database tables

Database tables are displayed as graphical boxes with all column fields.

JSON

One of the main advantages of Moon Modeler is the possibility to visually display nested structures.
The structures are displayed inside tables and also as separate graphical objects.… Read the rest

Relationships in ER diagrams for MariaDB

To create a new relation between two tables, click Relation on the toolbar and then click parent and child tables in your diagram.

New relation

In this example, click table customer and then table order.

New relation

The new relation line appears in the diagram and column customer_id is added to the child table order automatically.… Read the rest