Ruby Datamapper .count始终返回0

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

你可以在控制台中尝试User.all(:username=>params[:username])然后试试

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