導軌和字符串協會造成AssociationTypeMismatch錯誤

我已經在我的DevicePurchase模型如下 -導軌和字符串協會造成AssociationTypeMismatch錯誤

has_one :coupon_code, primary_key: 'coupon_code', foreign_key: 'name'

的應用IM在聯營合作與優惠券的名稱（字符串，即「SummerPromo123」）一COUPONCODE一個DevicePurchase而不是這個想法。我在上面添加的關聯看起來是工作，但是當我試圖DevicePurchase.last.update(...)我收到此 -

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/[email protected]/gems/activerecord-4.0.12/lib/active_record/associations/association.rb:224:in `raise_on_type_mismatch!' 
    from /Users/ryangrush/.rvm/gems/[email protected]/gems/activerecord-4.0.12/lib/active_record/associations/has_one_association.rb:25:in `replace' 
    from /Users/ryangrush/.rvm/gems/[email protected]/gems/activerecord-4.0.12/lib/active_record/associations/singular_association.rb:17:in `writer' 
    from /Users/ryangrush/.rvm/gems/[email protected]/gems/activerecord-4.0.12/lib/active_record/associations/builder/association.rb:78:in `coupon_code=' 
    from /Users/ryangrush/.rvm/gems/[email protected]/gems/activerecord-4.0.12/lib/active_record/attribute_assignment.rb:42:in `public_send' 
    from /Users/ryangrush/.rvm/gems/[email protected]/gems/activerecord-4.0.12/lib/active_record/attribute_assignment.rb:42:in `_assign_attribute' 
    from /Users/ryangrush/.rvm/gems/[email protected]/gems/activerecord-4.0.12/lib/active_record/attribute_assignment.rb:29:in `block in assign_attributes' 
    from /Users/ryangrush/.rvm/gems/[email protected]/gems/activerecord-4.0.12/lib/active_record/attribute_assignment.rb:23:in `each' 
    from /Users/ryangrush/.rvm/gems/[email protected]/gems/activerecord-4.0.12/lib/active_record/attribute_assignment.rb:23:in `assign_attributes' 
    from /Users/ryangrush/.rvm/gems/[email protected]/gems/activerecord-4.0.12/lib/active_record/persistence.rb:230:in `block in update' 
    from /Users/ryangrush/.rvm/gems/[email protected]/gems/activerecord-4.0.12/lib/active_record/transactions.rb:330:in `block in with_transaction_returning_status' 
    from /Users/ryangrush/.rvm/gems/[email protected]/gems/activerecord-4.0.12/lib/active_record/connection_adapters/abstract/database_statements.rb:203:in `block in transaction' 
    from /Users/ryangrush/.rvm/gems/[email protected]/gems/activerecord-4.0.12/lib/active_record/connection_adapters/abstract/database_statements.rb:211:in `within_new_transaction' 
    from /Users/ryangrush/.rvm/gems/[email protected]/gems/activerecord-4.0.12/lib/active_record/connection_adapters/abstract/database_statements.rb:203:in `transaction' 
    from /Users/ryangrush/.rvm/gems/[email protected]/gems/activerecord-4.0.12/lib/active_record/transactions.rb:209:in `transaction' 
    from /Users/ryangrush/.rvm/gems/[email protected]/gems/activerecord-4.0.12/lib/active_record/transactions.rb:327:in `with_transaction_returning_status' 
    from /Users/ryangrush/.rvm/gems/[email protected]/gems/activerecord-4.0.12/lib/active_record/persistence.rb:229:in `update' 
    from (irb):55 
    from /Users/ryangrush/.rvm/gems/[email protected]/gems/railties-4.0.12/lib/rails/commands/console.rb:90:in `start' 
    from /Users/ryangrush/.rvm/gems/[email protected]/gems/railties-4.0.12/lib/rails/commands/console.rb:9:in `start' 
    from /Users/ryangrush/.rvm/gems/[email protected]/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 >

我發現這個錯誤幾個StackOverflow的答案，但我認爲這個問題是與我聯繫。

**更新**

如果我跑DevicePurchase.last.update(coupon_code: CouponCode.last)我碰到下面的錯誤 -

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.

來源

2016-08-04 Ryan Grush

顯示引發錯誤的完整代碼。該代碼將幫助我們幫助你。：D –

確定它現在更新。 –

嘗試'DevicePurchase.last.update（coupon_code：Coupon.find_by_name（'yLVDnw'））'..我的意思是給它的實際'Coupon'對象..告訴我 –

確定的問題是，你有關聯的名字和列名相同。所以，當你嘗試DevicePurchase.last.update(coupon_code: 'yLVDnw')時，Rails認爲你會傳遞一個CouponCode對象，而不是像現在這樣的「string」值。這就是你得到的錯誤的原因。但是，如果您重新命名下面的關聯，則應該沒問題：

has_one :coupon, 
    primary_key: 'coupon_code', 
    foreign_key: 'name', 
    class_name: 'CouponCode'

來源

2016-08-04 21:33:25

那個作品，謝謝！ –

導軌和字符串協會造成AssociationTypeMismatch錯誤

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