#Main vs External Databases

The differences between main databases and external databases in NocoBase are primarily reflected in four aspects: database type support, collection type support, field type support, and backup and migration capabilities.

#1. Database Type Support

For more details, see: Data Source Manager

#Database Types

Database Type	Main Database Support	External Database Support
PostgreSQL	✅	✅
MySQL	✅	✅
MariaDB	✅	✅
KingbaseES	✅	✅
MSSQL	❌	✅
Oracle	❌	✅

#Collection Management

Collection Management	Main Database Support	External Database Support
Basic Management	✅	✅
Visual Management	✅	❌

#2. Collection Type Support

For more details, see: Collections

Collection Type	Main Database	External Database	Description
General	✅	✅	Basic collection
View	✅	✅	Data source view
Inheritance	✅	❌	Supports data model inheritance, master data source only
File	✅	❌	Supports file uploads, master data source only
Comment	✅	❌	Built-in comment system, master data source only
Calendar	✅	❌	Collection for calendar views
Expression	✅	❌	Supports formula calculations
Tree	✅	❌	For tree structure data modeling
SQL	✅	❌	Collection defined through SQL
External Connection	✅	❌	Connection collection for external data sources, limited functionality

#3. Field Type Support

For more details, see: Collection Fields

#Basic Types

Field Type	Main Database	External Database
Single Line Text	✅	✅
Long Text	✅	✅
Phone	✅	✅
Email	✅	✅
URL	✅	✅
Integer	✅	✅
Number	✅	✅
Percentage	✅	✅
Password	✅	✅
Color	✅	✅
Icon	✅	✅

#Choice Types

Field Type	Main Database	External Database
Checkbox	✅	✅
Single select	✅	✅
Multiple Select	✅	✅
Radio Group	✅	✅
Checkbox group	✅	✅
China region	✅	❌

#Media Types

Field Type	Main Database	External Database
Media	✅	✅
Markdown	✅	✅
Markdown(Vditor)	✅	✅
Rich Text	✅	✅
Attachment(Association)	✅	❌
Attachment(URL)	✅	✅

#Date & Time Types

Field Type	Main Database	External Database
Datetime(with time zone)	✅	✅
Datetime(without time zone)	✅	✅
Unix timestamp	✅	✅
Date(without time)	✅	✅
Time	✅	✅

#Geometric Types

Field Type	Main Database	External Database
Point	✅	✅
Line	✅	✅
Circle	✅	✅
Polygon	✅	✅

#Advanced Types

Field Type	Main Database	External Database
UUID	✅	✅
Nano ID	✅	✅
Sort	✅	✅
Formula	✅	✅
Sequence	✅	✅
JSON	✅	✅
Collection selector	✅	❌
Encryption	✅	✅

#System Info Fields

Field Type	Main Database	External Database
Created at	✅	✅
Last updated at	✅	✅
Created by	✅	❌
Last updated by	✅	❌
Table OID	✅	❌

#Association Types

Field Type	Main Database	External Database
One-to-one	✅	✅
One-to-many	✅	✅
Many-to-one	✅	✅
Many-to-many	✅	✅
Many-to-many (array)	✅	✅

#4. Backup and Migration Support Comparison

Feature	Main Database	External Database
Backup & Restore	✅	❌ (User managed)
Migration Management	✅	❌ (User managed)

#Summary Comparison

Comparison Item	Main Database	External Database
Database Types	PostgreSQL, MySQL, MariaDB, KingbaseES	PostgreSQL, MySQL, MariaDB, MSSQL, Oracle, KingbaseES
Collection Type Support	All collection types	Only general and view collections
Field Type Support	All field types	All field types except attachment fields
Backup & Migration	Built-in support	User managed

#Recommendations

• If you are using NocoBase to build a new business system, please use the main database, which will allow you to use NocoBase's complete functionality.
• If you are using NocoBase to connect to other systems' databases for basic CRUD operations, then use external databases.