Ruby on rails 重命名了一个表，我收到了错误

我将一个表命名为Types，并意识到它是一个保留字，所以我将其重命名为“Category”

现在，当我尝试执行ActiveRecord查询时，出现以下错误：

PG::UndefinedTable: ERROR:  relation "categories" does not exist
LINE 5:                WHERE a.attrelid = '"categories"'::regclass
                                          ^
:               SELECT a.attname, format_type(a.atttypid, a.atttypmod),
                     pg_get_expr(d.adbin, d.adrelid), a.attnotnull, a.atttypid, a.atttypmod
                FROM pg_attribute a LEFT JOIN pg_attrdef d
                  ON a.attrelid = d.adrelid AND a.attnum = d.adnum
               WHERE a.attrelid = '"categories"'::regclass
                 AND a.attnum > 0 AND NOT a.attisdropped
               ORDER BY a.attnum

我已经回顾了我所有的代码，并更改了所有的关系名称、模型、控制器等…但我不知道这个错误是从哪里来的。或者它意味着什么。这是我的category.rb：

class Category < ActiveRecord::Base
has_many :projects

end

下面是我在用户模型中尝试做的事情，因为我希望代码能够按照当前的_user.contributions _by _category阅读

此外，在我的项目模型中，我有：

class Project < ActiveRecord::Base
    belongs_to :user, :foreign_key => 'user_id'
    belongs_to :category, :foreign_key => 'category_id' #should change this to a has one association
    has_many :users
    has_many :payments
    has_many :updates
    has_many :comments
    has_one :imapct 

....

end

这是我的模式：

ActiveRecord::Schema.define(version: 20150930040619) do

  # These are extensions that must be enabled in order to support this database
  enable_extension "plpgsql"

  create_table "categories", force: :cascade do |t|
    t.string "category_type"
  end

  create_table "comments", force: :cascade do |t|
    t.text     "content"
    t.integer  "user_id"
    t.integer  "project_id"
    t.datetime "created_at"
    t.datetime "updated_at"
  end

  create_table "entrepreneurs", force: :cascade do |t|
    t.string   "first_name"
    t.string   "last_name"
    t.string   "password_digest"
    t.text     "about"
    t.string   "location"
    t.integer  "age"
    t.float    "repayment_rate"
    t.integer  "project_id"
    t.datetime "created_at"
    t.datetime "updated_at"
  end

  create_table "impacts", force: :cascade do |t|
    t.integer  "ppl_hired",            default: 0
    t.integer  "ppl_schooled",         default: 0
    t.integer  "improved_housing",     default: 0
    t.integer  "improved_nourishment", default: 0
    t.integer  "improved_medical",     default: 0
    t.integer  "community_resource",   default: 0
    t.integer  "project_id"
    t.datetime "created_at"
    t.datetime "updated_at"
  end

  create_table "payments", force: :cascade do |t|
    t.string   "first_name"
    t.string   "last_name"
    t.float    "amount"
    t.integer  "cc_num"
    t.integer  "exp_month"
    t.integer  "exp_year"
    t.integer  "cvs"
    t.integer  "user_id"
    t.integer  "project_id"
    t.datetime "created_at"
    t.datetime "updated_at"
    t.text     "comments"
  end

  create_table "projects", force: :cascade do |t|
    t.string   "name"
    t.text     "url"
    t.text     "description"
    t.float    "money_needed",     default: 0.0
    t.float    "money_raised",     default: 0.0
    t.float    "interest_offered", default: 0.0
    t.datetime "end_date"
    t.integer  "category_id"
    t.integer  "user_id"
    t.datetime "created_at"
    t.datetime "updated_at"
  end

  create_table "update_comments", force: :cascade do |t|
  end

  create_table "updates", force: :cascade do |t|
    t.text    "content"
    t.string  "url"
    t.integer "project_id"
    t.string  "date"
  end

  create_table "users", force: :cascade do |t|
    t.string   "first_name"
    t.string   "last_name"
    t.string   "user_name"
    t.string   "password_digest"
    t.string   "impact"
    t.text     "pic_url"
    t.text     "quote"
    t.integer  "payment_id"
    t.integer  "project_id"
    t.datetime "created_at"
    t.datetime "updated_at"
    t.boolean  "admin"
  end

---

数据库的状态如何？试着运行rakedb:resetwill！重置做什么？根据rails文档，rake db:reset任务将删除数据库并重新设置。这在功能上等同于rake db:drop db:setup.：我得到了一个名称错误：未初始化的常量Typecategories肯定是您想要命名表的名称。回滚迁移，更正迁移中的表名，然后重新迁移。还要确保您的db/seeds.rb和代码空间中的所有其他文件没有其他类型的引用。

class Project < ActiveRecord::Base
    belongs_to :user, :foreign_key => 'user_id'
    belongs_to :category, :foreign_key => 'category_id' #should change this to a has one association
    has_many :users
    has_many :payments
    has_many :updates
    has_many :comments
    has_one :imapct 

....

end

   List of relations
 Schema |       Name        | Type  |    Owner    
--------+-------------------+-------+-------------
 public | categories        | table | seinnaidess
 public | comments          | table | seinnaidess
 public | entrepreneurs     | table | seinnaidess
 public | impacts           | table | seinnaidess
 public | payments          | table | seinnaidess
 public | projects          | table | seinnaidess
 public | schema_migrations | table | seinnaidess
 public | update_comments   | table | seinnaidess
 public | updates           | table | seinnaidess
 public | users             | table | seinnaidess

ActiveRecord::Schema.define(version: 20150930040619) do

  # These are extensions that must be enabled in order to support this database
  enable_extension "plpgsql"

  create_table "categories", force: :cascade do |t|
    t.string "category_type"
  end

  create_table "comments", force: :cascade do |t|
    t.text     "content"
    t.integer  "user_id"
    t.integer  "project_id"
    t.datetime "created_at"
    t.datetime "updated_at"
  end

  create_table "entrepreneurs", force: :cascade do |t|
    t.string   "first_name"
    t.string   "last_name"
    t.string   "password_digest"
    t.text     "about"
    t.string   "location"
    t.integer  "age"
    t.float    "repayment_rate"
    t.integer  "project_id"
    t.datetime "created_at"
    t.datetime "updated_at"
  end

  create_table "impacts", force: :cascade do |t|
    t.integer  "ppl_hired",            default: 0
    t.integer  "ppl_schooled",         default: 0
    t.integer  "improved_housing",     default: 0
    t.integer  "improved_nourishment", default: 0
    t.integer  "improved_medical",     default: 0
    t.integer  "community_resource",   default: 0
    t.integer  "project_id"
    t.datetime "created_at"
    t.datetime "updated_at"
  end

  create_table "payments", force: :cascade do |t|
    t.string   "first_name"
    t.string   "last_name"
    t.float    "amount"
    t.integer  "cc_num"
    t.integer  "exp_month"
    t.integer  "exp_year"
    t.integer  "cvs"
    t.integer  "user_id"
    t.integer  "project_id"
    t.datetime "created_at"
    t.datetime "updated_at"
    t.text     "comments"
  end

  create_table "projects", force: :cascade do |t|
    t.string   "name"
    t.text     "url"
    t.text     "description"
    t.float    "money_needed",     default: 0.0
    t.float    "money_raised",     default: 0.0
    t.float    "interest_offered", default: 0.0
    t.datetime "end_date"
    t.integer  "category_id"
    t.integer  "user_id"
    t.datetime "created_at"
    t.datetime "updated_at"
  end

  create_table "update_comments", force: :cascade do |t|
  end

  create_table "updates", force: :cascade do |t|
    t.text    "content"
    t.string  "url"
    t.integer "project_id"
    t.string  "date"
  end

  create_table "users", force: :cascade do |t|
    t.string   "first_name"
    t.string   "last_name"
    t.string   "user_name"
    t.string   "password_digest"
    t.string   "impact"
    t.text     "pic_url"
    t.text     "quote"
    t.integer  "payment_id"
    t.integer  "project_id"
    t.datetime "created_at"
    t.datetime "updated_at"
    t.boolean  "admin"
  end