为什么Postgresql会像Geokit这样失败？

Question

我刚刚开始使用Rails为我正在构建的应用程序玩geokit.我的记录得到了地理编码,但是当我进入控制台看看我能用它做什么时它会爆炸以下内容:用户是我的数据库中带有lat和lng的用户对象

>> Restaurant.find(:all, :origin => user) 

  Restaurant Load (0.0ms)   PGError: ERROR: operator does not exist: 
numeric - character varying 
LINE 1: ...*, SQRT(POW(111.1819*(-33.872517-restauran... 
 ^ 
HINT: No operator matches the given name and argument type(s). You 
might need to add explicit type casts. 
: SELECT *, SQRT(POW(111.1819*(-33.872517-restaurants.lat),2)+ 
 POW(76.7136337302943*(151.205536-restaurants.lng),2)) 
 AS distance FROM "restaurants" 
ActiveRecord::StatementInvalid: PGError: ERROR:  operator does not 
exist: numeric - character varying 
LINE 1: ...*,                   SQRT(POW(111.1819*(-33.872517- 
restauran... 
                                                             ^ 
HINT:  No operator matches the given name and argument type(s). You 
might need to add explicit type casts. 
: SELECT *,                   SQRT(POW(111.1819*(-33.872517- 
restaurants.lat),2)+ 
                  POW(76.7136337302943*(151.205536-restaurants.lng), 
2)) 
 AS distance FROM "restaurants" 
        from /Users/chris/projects/mine/lunchdecider/vendor/rails/ 
activerecord/lib/active_record/connection_adapters/abstract_adapter.rb: 
212:in `log' 
        from /Users/chris/projects/mine/lunchdecider/vendor/rails/ 
activerecord/lib/active_record/connection_adapters/ 
postgresql_adapter.rb:538:in `execute' 
        from /Users/chris/projects/mine/lunchdecider/vendor/rails/ 
activerecord/lib/active_record/connection_adapters/ 
postgresql_adapter.rb:1019:in `select_raw' 
        from /Users/chris/projects/mine/lunchdecider/vendor/rails/ 
activerecord/lib/active_record/connection_adapters/ 
postgresql_adapter.rb:1006:in `select' 
        from /Users/chris/projects/mine/lunchdecider/vendor/rails/ 
activerecord/lib/active_record/connection_adapters/abstract/ 
database_statements.rb:7:in `select_all_without_query_cache' 
        from /Users/chris/projects/mine/lunchdecider/vendor/rails/ 
activerecord/lib/active_record/connection_adapters/abstract/ 
query_cache.rb:62:in `select_all' 
        from /Users/chris/projects/mine/lunchdecider/vendor/rails/ 
activerecord/lib/active_record/base.rb:661:in `find_by_sql' 
        from /Users/chris/projects/mine/lunchdecider/vendor/rails/ 
activerecord/lib/active_record/base.rb:1548:in `find_every' 
        from /Users/chris/projects/mine/lunchdecider/vendor/rails/ 
activerecord/lib/active_record/base.rb:615:in `find' 
        from /Users/chris/projects/mine/lunchdecider/vendor/plugins/geokit- 
rails/lib/geokit-rails/acts_as_mappable.rb:138:in `find' 
        from (irb):10 

有什么想法可以解决这个问题吗？遗憾的是,当我尝试搜索我的错误消息时谷歌帮助不大...

Answer 1

在您的迁移中,您可能创建了restaurants.lat和restaurants.lng作为字符串(字符变化),而它们应该是浮点数.Postgres不会为你投这个.改变列类型你应该没问题.