#Database

Database is a core component of database-type data sources (DataSource). Each database-type data source has a corresponding Database instance, accessible via dataSource.db. The main data source's database instance also has a convenient alias app.db. Familiarizing yourself with db's common methods is fundamental to writing server-side plugins.

#Database Components

A typical Database consists of the following parts:

• Collection: Defines data table structure.
• Model: Corresponds to ORM models (usually managed by Sequelize).
• Repository: Repository layer that encapsulates data access logic, providing higher-level operation methods.
• FieldType: Field types.
• FilterOperator: Operators used for filtering.
• Event: Lifecycle events and database events.

#Usage Timing in Plugins

#Things Suitable for the beforeLoad Stage

At this stage, database operations cannot be performed yet. It is suitable for static class registration or event listening.

• db.registerFieldTypes() - Register custom field types
• db.registerModels() - Register custom model classes
• db.registerRepositories() - Register custom repository classes
• db.registerOperators() - Register custom filter operators
• db.on() - Listen to database-related events

#Things Suitable for the load Stage

At this stage, all preceding class definitions and events have been loaded, so loading data tables won't have missing or omitted dependencies.

• db.defineCollection() - Define new data tables
• db.extendCollection() - Extend existing data table configurations

However, for defining plugin built-in tables, it's more recommended to place them in the ./src/server/collections directory. See Collections.

#Data Operations

Database provides two main ways to access and operate data:

#Operations via Repository

const repo = db.getRepository('users');
const user = await repo.findOne({ filter: { id: 1 } });

The Repository layer is typically used to encapsulate business logic, such as pagination, filtering, permission checks, etc.

#Operations via Model

const UserModel = db.getModel('users');
const user = await UserModel.findByPk(1);

The Model layer directly corresponds to ORM entities, suitable for lower-level database operations.

#Which Stages Allow Database Operations?

#Plugin Lifecycle

#App Events

#Database Events/Hooks

#Related Links

• Collections - Define or extend data table structures with code
• DataSourceManager - Manage multiple data sources and their database instances
• Context - Access the db instance in requests
• Plugin - Plugin class lifecycle, member methods, and the app object
• Event - Application-level and database-level event listening and handling