Ruby Datamapper .count始终返回0

Question

每当我尝试从datamapper计算返回的记录时，它总是返回0，无论是否有用户。

User.count(:username=>params[:username])

class User
  include DataMapper::Resource

  property :id,  Serial
  property :username,  String, unique_index: true, required: true, length: 3..32
  property :password,  String, required: true, length: 5..64
  property :email,  String, unique_index: true, required: true, format: :email_address

end

Answer 1

您可以在控制台中尝试User.all(:username=>params[:username])吗？ 然后尝试

那个ENV的

User.count(:username=>params[:username])