Quick start guide for MongoDB schema design in Moon Modeler.
The following text explains how to design a new database structure for MongoDB.
This article is divided into the following sections:
- New project
- MongoDB schema design – collections
- MongoDB schema design – documents
- Embedded documents vs References
- Code generation
1. New Project
To create a new project in Moon Modeler click the New item on the toolbar. A new modal form opens. Select MongoDB project type and click Create a new project. A new project is created and you can start modeling your database structure.
2. Design collections
Start adding new objects to your diagram, you can add the following MongoDB specific items to your design: Collections, Documents, References, Views, Functions, and Other objects. To add new MongoDB collection to your design, click the Collection item on the toolbar and then click the main diagram area.
A new graphical representative appears in the diagram. You can edit MongoDB collection properties via the Right Side panel, where all necessary settings can be easily specified. There is no need to confirm changes, all modifications are stored to the model automatically. In case you make a mistake, use UNDO to revert the changes back to the previous state.
If you prefer modal dialogs, double click an item on the diagram or open popup and choose Edit:
A modal form opens and you can navigate to an appropriate section by clicking a particular tab on the form. One of the advantages of using modal forms is the possibility to use the larger area for e.g. fields definition, for the specification of before and after scripts sections and so on.
MongoDB collection properties
In section Details, collection settings can be specified. For example caped collection, validation level, etc.
In section Fields, you can add new fields to collections to your MongoDB schema design. Specify new field name, datatype and click Add.
The following abbreviations are used on the form:
ARR – indicates Array.
NN – represents the required field (not null)
Note: Both the settings are also displayed in the graphical representatives in your diagrams.
To access areas where MongoDB field specifics can be modified, click the arrow icon left to the field name. The additional area expands and you can specify validation settings, description and sample data.
3. Design documents
MongoDB documents are objects that can be embedded in collections or other documents.
Example: See collection customer. Field contact contains embedded document contact. And this document contains two fields: addresses and phones. Both the fields are arrays and contain embedded documents address and phone.
To create a new document, click the Document icon on the toolbar and then click the main area.
Embedding documents to collections
To embed the document to a collection, edit the target collection and select the document name from the Datatype selection box.
Collections vs Documents in MongoDB design process
During your design process, you might consider changing the document to a collection or vice versa. In order to avoid manual redefinition, enable or disable the Document switch in properties. This switch allows you to change the document to the collection and let the tool generate MongoDB validation script for the collection.
4. References in MongoDB schema design
References represent links between collections. In the following example, the collection article contains a reference to the collection vendor. In the article collection, only ID is stored. Compare it with the vendor collection where field address contains an embedded document address. Such field contains full data, incl. street, city, zip and country values.
Tip: Lear more about noSQL data modeling
5. Code generation for MongoDB schema design
To preview the validation script for your MongoDB schema design, click the Script tab on the collection detail. Moon Modeler can also generate scripts for the project. To see the full script click the Script item on the main toolbar. A modal form opens and the script is displayed with formatting and syntax highlighting.
To save scripts to files, click Save script, define a location where the output should be stored and finish the action.
Visualization of existing databases
in Moon Modeler you can create a connection to the MongoDB database and use reverse engineering to create a project with an ER diagram. For more information, see Visualization of an existing database.