为什么 Postgresql 使用 Geokit 会失败？

Question

我刚刚开始使用 Geokit 和 Rails 来开发我的应用程序 建筑。我已经对我的记录进行了地理编码，但是当我去的时候 进入控制台看看我能用它做什么，结果爆炸了 添加以下内容： user 是一个用户对象，其中包含我的 lat 和 lng 数据库

>> 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？不幸的是谷歌并不多 当我尝试搜索错误消息时提供帮助...

Answer 1

在迁移过程中，您可能将restaurant.lat 和restaurants.lng 创建为字符串（字符不同），而它们应该是浮点数。 Postgres 不会为你投射它。改变列类型就可以了。