Rails数据库配置 #

一、数据库配置文件 #

1.1 配置文件位置 #

text

config/database.yml

1.2 基本配置结构 #

yaml

default: &default
  adapter: postgresql
  encoding: unicode
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>

development:
  <<: *default
  database: myapp_development

test:
  <<: *default
  database: myapp_test

production:
  <<: *default
  database: myapp_production
  username: myapp
  password: <%= ENV['MYAPP_DATABASE_PASSWORD'] %>

二、数据库适配器 #

2.1 PostgreSQL #

yaml

default: &default
  adapter: postgresql
  encoding: unicode
  host: localhost
  port: 5432
  pool: 5
  username: postgres
  password: <%= ENV['DB_PASSWORD'] %>

2.2 MySQL #

yaml

default: &default
  adapter: mysql2
  encoding: utf8mb4
  host: localhost
  port: 3306
  pool: 5
  username: root
  password: <%= ENV['DB_PASSWORD'] %>

2.3 SQLite #

yaml

default: &default
  adapter: sqlite3
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
  timeout: 5000

development:
  <<: *default
  database: storage/development.sqlite3

三、连接池配置 #

3.1 连接池参数 #

yaml

default: &default
  adapter: postgresql
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
  timeout: 5000
  checkout_timeout: 5
  reaping_frequency: 60

3.2 连接池参数说明 #

参数	说明	默认值
pool	连接池大小	5
timeout	获取连接超时时间	5000ms
checkout_timeout	等待连接超时	5s
reaping_frequency	清理断开连接频率	60s

四、多数据库配置 #

4.1 基本多数据库 #

yaml

development:
  primary:
    adapter: postgresql
    database: myapp_development
  replica:
    adapter: postgresql
    database: myapp_replica
    replica: true

4.2 读写分离 #

yaml

production:
  primary:
    adapter: postgresql
    database: myapp_production
    host: primary.example.com
  replica:
    adapter: postgresql
    database: myapp_production
    host: replica.example.com
    replica: true

4.3 使用多数据库 #

ruby

# app/models/application_record.rb
class ApplicationRecord < ActiveRecord::Base
  self.abstract_class = true
  connects_to database: { writing: :primary, reading: :replica }
end

# app/models/user.rb
class User < ApplicationRecord
  # 自动使用主库写入，从库读取
end

# 手动切换数据库
User.connected_to(role: :reading) do
  User.all
end

五、环境变量配置 #

5.1 使用环境变量 #

yaml

production:
  adapter: postgresql
  host: <%= ENV['DB_HOST'] %>
  port: <%= ENV['DB_PORT'] || 5432 %>
  database: <%= ENV['DB_NAME'] %>
  username: <%= ENV['DB_USER'] %>
  password: <%= ENV['DB_PASSWORD'] %>

5.2 .env文件 #

bash

# .env
DB_HOST=localhost
DB_PORT=5432
DB_NAME=myapp_development
DB_USER=postgres
DB_PASSWORD=secret

六、总结 #

6.1 核心要点 #

要点	说明
配置文件	config/database.yml
适配器	PostgreSQL、MySQL、SQLite
连接池	pool、timeout配置
多数据库	读写分离
环境变量	安全存储密码

6.2 下一步 #

现在你已经掌握了数据库配置，接下来让我们学习迁移基础，深入了解Rails的数据库迁移系统！