Rails模型选择字段

debugcn 发表于 Dev

moddayjob

我是Rails的新手。在Django中，模型字段有一个choices选项，如下所示：

class Student(models.Model):
    FRESHMAN = 'FR'
    SOPHOMORE = 'SO'
    JUNIOR = 'JR'
    SENIOR = 'SR'
    GRADUATE = 'GR'
    YEAR_IN_SCHOOL_CHOICES = [
        (FRESHMAN, 'Freshman'),
        (SOPHOMORE, 'Sophomore'),
        (JUNIOR, 'Junior'),
        (SENIOR, 'Senior'),
        (GRADUATE, 'Graduate'),
    ]
    year_in_school = models.CharField(
        max_length=2,
        choices=YEAR_IN_SCHOOL_CHOICES,
        default=FRESHMAN,
    )

在Rails中实现相同目标的方法是什么？就我而言，我想要一个activity可以包含值的字段to-read, reading, read, not-finished, reading_again。提前致谢

杜莫兹（ThéoDumez）

您好，您可以在模型中添加验证：

class Student < ApplicationRecord
  validates :activity, inclusion: { in: ["to-read", "reading", "read", "not-finished", "reading_again"],
    message: "%{value} is not a valid activity" }
end

选择必须放在表单视图中，如下所示：

<%= form_with model: @student, class: "" do |f| %>
  <%= select_tag(:activity,
    options_for_select(["to-read", "reading", "read", "not-finished", "reading_again"], @student.activity) %>
  <%= f.submit "Create" %>
<% end %>

在数据库模式中，您应该具有：

create_table "students", force: :cascade do |t|
  t.string "activity"
  t.datetime "created_at", precision: 6, null: false
  t.datetime "updated_at", precision: 6, null: false
end

不要忘记：如果您的数据库架构不正确，则必须进行迁移，而不能直接编辑您的schema.rb：https : //guides.rubyonrails.org/active_record_migrations.html

希望这个问题的答案

最好，Théo

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