Rails 与导致 AssociationTypeMismatch 错误的字符串的关联
Rails associations with string causing AssociationTypeMismatch error
我的 DevicePurchase 模型中有以下内容 -
has_one :coupon_code, primary_key: 'coupon_code', foreign_key: 'name'
我正在开发的应用程序通过优惠券的名称（字符串，即 "SummerPromo123"）将 DevicePurchase 与 CouponCode 相关联，而不是想法。我在上面添加的关联看起来有效，但是当我尝试 DevicePurchase.last.update(...) 时，我收到了这个 -
DevicePurchase.last.update(coupon_code: 'yLVDnw')
DevicePurchase Load (2.4ms) SELECT "device_purchases".* FROM "device_purchases" ORDER BY "device_purchases"."id" DESC LIMIT 1
(0.2ms) BEGIN
(0.3ms) ROLLBACK
ActiveRecord::AssociationTypeMismatch: CouponCode(#70224191762780) expected, got String(#70224129222500)
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/associations/association.rb:224:in `raise_on_type_mismatch!'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/associations/has_one_association.rb:25:in `replace'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/associations/singular_association.rb:17:in `writer'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/associations/builder/association.rb:78:in `coupon_code='
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/attribute_assignment.rb:42:in `public_send'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/attribute_assignment.rb:42:in `_assign_attribute'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/attribute_assignment.rb:29:in `block in assign_attributes'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/attribute_assignment.rb:23:in `each'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/attribute_assignment.rb:23:in `assign_attributes'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/persistence.rb:230:in `block in update'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/transactions.rb:330:in `block in with_transaction_returning_status'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/connection_adapters/abstract/database_statements.rb:203:in `block in transaction'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/connection_adapters/abstract/database_statements.rb:211:in `within_new_transaction'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/connection_adapters/abstract/database_statements.rb:203:in `transaction'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/transactions.rb:209:in `transaction'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/transactions.rb:327:in `with_transaction_returning_status'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/persistence.rb:229:in `update'
from (irb):55
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/railties-4.0.12/lib/rails/commands/console.rb:90:in `start'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/railties-4.0.12/lib/rails/commands/console.rb:9:in `start'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/railties-4.0.12/lib/rails/commands.rb:62:in `<top (required)>'
from bin/rails:4:in `require'
from bin/rails:4:in `<main>'2.2.4 :056 >
我在 Whosebug 找到了一些针对该错误的答案，但我认为问题出在我的关联上。
** 更新 **
如果我 运行 DevicePurchase.last.update(coupon_code: CouponCode.last) 我得到以下错误 -
SELECT 1 AS one FROM "coupon_codes" WHERE ("coupon_codes"."name" = 1188 AND "coupon_codes"."id" != 1188) LIMIT 1
PG::UndefinedFunction: ERROR: operator does not exist: text = integer
LINE 1: ...FROM "coupon_codes" WHERE ("coupon_codes"."name" = 1188 AND...
^
HINT: No operator matches the given name and argument type(s). You might need to add explicit type casts.
: SELECT 1 AS one FROM "coupon_codes" WHERE ("coupon_codes"."name" = 1188 AND "coupon_codes"."id" != 1188) LIMIT 1
(0.2ms) ROLLBACK
ActiveRecord::StatementInvalid: PG::UndefinedFunction: ERROR: operator does not exist: text = integer
LINE 1: ...FROM "coupon_codes" WHERE ("coupon_codes"."name" = 1188 AND...
^
HINT: No operator matches the given name and argument type(s). You might need to add explicit type casts.
好的，问题是，您得到的关联名称和列名称相同。因此，当您尝试 DevicePurchase.last.update(coupon_code: 'yLVDnw') 时，Rails 认为您将传递给它一个 CouponCode 对象，而不是您现在拥有的 "string" 值。这就是你得到错误的原因。但是如果你像下面这样重命名关联，你应该没问题：
has_one :coupon,
primary_key: 'coupon_code',
foreign_key: 'name',
class_name: 'CouponCode'
我的 DevicePurchase 模型中有以下内容 -
has_one :coupon_code, primary_key: 'coupon_code', foreign_key: 'name'
我正在开发的应用程序通过优惠券的名称（字符串，即 "SummerPromo123"）将 DevicePurchase 与 CouponCode 相关联，而不是想法。我在上面添加的关联看起来有效，但是当我尝试 DevicePurchase.last.update(...) 时，我收到了这个 -
DevicePurchase.last.update(coupon_code: 'yLVDnw')
DevicePurchase Load (2.4ms) SELECT "device_purchases".* FROM "device_purchases" ORDER BY "device_purchases"."id" DESC LIMIT 1
(0.2ms) BEGIN
(0.3ms) ROLLBACK
ActiveRecord::AssociationTypeMismatch: CouponCode(#70224191762780) expected, got String(#70224129222500)
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/associations/association.rb:224:in `raise_on_type_mismatch!'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/associations/has_one_association.rb:25:in `replace'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/associations/singular_association.rb:17:in `writer'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/associations/builder/association.rb:78:in `coupon_code='
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/attribute_assignment.rb:42:in `public_send'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/attribute_assignment.rb:42:in `_assign_attribute'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/attribute_assignment.rb:29:in `block in assign_attributes'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/attribute_assignment.rb:23:in `each'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/attribute_assignment.rb:23:in `assign_attributes'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/persistence.rb:230:in `block in update'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/transactions.rb:330:in `block in with_transaction_returning_status'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/connection_adapters/abstract/database_statements.rb:203:in `block in transaction'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/connection_adapters/abstract/database_statements.rb:211:in `within_new_transaction'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/connection_adapters/abstract/database_statements.rb:203:in `transaction'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/transactions.rb:209:in `transaction'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/transactions.rb:327:in `with_transaction_returning_status'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/activerecord-4.0.12/lib/active_record/persistence.rb:229:in `update'
from (irb):55
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/railties-4.0.12/lib/rails/commands/console.rb:90:in `start'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/railties-4.0.12/lib/rails/commands/console.rb:9:in `start'
from /Users/ryangrush/.rvm/gems/ruby-2.2.4@myautobrain/gems/railties-4.0.12/lib/rails/commands.rb:62:in `<top (required)>'
from bin/rails:4:in `require'
from bin/rails:4:in `<main>'2.2.4 :056 >
我在 Whosebug 找到了一些针对该错误的答案，但我认为问题出在我的关联上。
** 更新 **
如果我 运行 DevicePurchase.last.update(coupon_code: CouponCode.last) 我得到以下错误 -
SELECT 1 AS one FROM "coupon_codes" WHERE ("coupon_codes"."name" = 1188 AND "coupon_codes"."id" != 1188) LIMIT 1
PG::UndefinedFunction: ERROR: operator does not exist: text = integer
LINE 1: ...FROM "coupon_codes" WHERE ("coupon_codes"."name" = 1188 AND...
^
HINT: No operator matches the given name and argument type(s). You might need to add explicit type casts.
: SELECT 1 AS one FROM "coupon_codes" WHERE ("coupon_codes"."name" = 1188 AND "coupon_codes"."id" != 1188) LIMIT 1
(0.2ms) ROLLBACK
ActiveRecord::StatementInvalid: PG::UndefinedFunction: ERROR: operator does not exist: text = integer
LINE 1: ...FROM "coupon_codes" WHERE ("coupon_codes"."name" = 1188 AND...
^
HINT: No operator matches the given name and argument type(s). You might need to add explicit type casts.
好的，问题是，您得到的关联名称和列名称相同。因此，当您尝试 DevicePurchase.last.update(coupon_code: 'yLVDnw') 时，Rails 认为您将传递给它一个 CouponCode 对象，而不是您现在拥有的 "string" 值。这就是你得到错误的原因。但是如果你像下面这样重命名关联，你应该没问题：
has_one :coupon,
primary_key: 'coupon_code',
foreign_key: 'name',
class_name: 'CouponCode'