小编Mik*_*ski的帖子

我正在尝试将.hex文件上传到Arduino.通过IDE上传代码没有任何问题(如眨眼示例或其他任何内容).端口和板是正确的.

因此,当我尝试上传时出现问题

avrdude -pm328p -carduino -P/dev/tty.usbmodemfd121 -b57600 -D -Uflash:w:grbl_v0_8c_atmega328p_16mhz_9600.hex -v -v -v -v

avrdude: Version 6.1, compiled on Mar 23 2014 at 04:42:55
     Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
     Copyright (c) 2007-2014 Joerg Wunsch

     System wide configuration file is "/usr/local/Cellar/avrdude/6.1/etc/avrdude.conf"
     User configuration file is "/Users/Mikhail/.avrduderc"
     User configuration file does not exist or is not a regular file, skipping

     Using Port                    : /dev/tty.usbmodemfd121
     Using Programmer              : arduino
     Overriding Baud Rate          : 57600
avrdude: Send: 0 [30]   [20] 
avrdude: Send: 0 [30] …

我有一个从.xslx文件导入一些数据的应用程序.它适用于单个文件和多个文件.我将file_field_tag功能用于这些目的.但由于我有子文件夹,我想允许用户选择特定文件夹来处理其中的所有文件,包括子文件夹.据我所知,file_field_tag没有任何可能性.

我怎么处理它？

我有一个 Rails 应用程序，最初使用 SQLite3 创建。现在我需要将它与所有数据一起移动到 PostgreSQL。

我尝试按照“如何从 SQLite 迁移到 PostgreSQL (Rails) ”中的建议使用：

sqlite3 development.db .dump | psql dbname username

就我而言，它是：

sqlite3 development.sqlite3 .dump | psql dev_db deployer

我得到了这个：

ERROR:  syntax error at or near "PRAGMA"
LINE 1: PRAGMA foreign_keys=OFF;
    ^
BEGIN
ERROR:  syntax error at or near "AUTOINCREMENT"
LINE 1: CREATE TABLE "people" ("id" INTEGER PRIMARY KEY AUTOINCREMEN...

那些只是 SQL 实现的差异吗？我该如何解决这个问题？

我尝试将我的应用程序从Rails 4迁移到Rails 5这是我的迁移:

class AddRevealedIdsToUser < ActiveRecord::Migration[5.0]
  def change
    add_column :users, :revealed_ids, :text, default: []
  end
end

和型号:

serialize :revealed_ids

它在Rails 4中运行得很好,现在我有一个错误:

== 20160416214334 AddRevealedIdsToUser: migrating =============================
-- add_column(:users, :revealed_ids, :text, {:default=>[]})
rails aborted!
StandardError: An error has occurred, this and all later migrations canceled:

can't quote Array
/usr/local/lib/ruby/gems/2.3.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/quoting.rb:177:in `_quote'
/usr/local/lib/ruby/gems/2.3.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/postgresql/quoting.rb:96:in `_quote'

怎么解决？

我有这个字符串,我需要转换为哈希:

str = '{:gender=>{:content=>"male"}, :names=>[{:first=>"Atair", :last=>"Goron"}], :addresses=>[{:country=>"GB", :state=>"ENG", :city=>"London"}], :emails=>[{:address=>"agoron@keolis.com", :address_md5=>"971b2fd0b83c900a5ca62c91dab80dd9"}, {:address=>"atair.godon.75@facebook.com", :address_md5=>"a0d958c1396300a344356d57b6836f9e"}], :jobs=>[{:title=>"Chief Executive Officer", :organization=>"Kolis UK and Eire"}, {:title=>"Deputy Managing Director", :organization=>"Kolis UK", :date_range=>{:start=>"2008-04-01", :end=>"2010-04-01"}}, {:title=>"Project Director", :organization=>"Keolis UK", :date_range=>{:start=>"2004-04-01", :end=>"2008-04-01"}}, {:title=>"Strategic Planning Director", :organization=>"Eurostar", :date_range=>{:start=>"2002-04-01", :end=>"2004-04-01"}}, {:title=>"Commercial Director, Business Markets", :organization=>"Eurostar", :date_range=>{:start=>"1999-11-01", :end=>"2002-04-01"}}, {:title=>"Brand Manager", :organization=>"Eurostar", :date_range=>{:start=>"1998-06-01", :end=>"1999-11-01"}}, {:title=>"Business Forecasting Manager", :organization=>"Eurostar", :date_range=>{:start=>"1997-08-01", :end=>"1998-06-01"}}, {:title=>"Principal Consultant", :organization=>"Steer Davies Gleave", :date_range=>{:start=>"1995-04-01", :end=>"1997-08-01"}}, {:title=>"Transport Consultant", :organization=>"Sir Alexander Gibb and Part", :date_range=>{:start=>"1990-01-01", :end=>"1995-12-31"}}], :educations=>[{:school=>"U. of London"}, {:school=>"University College London, U. …

假设我的网站有三个表格:

class Group < ActiveRecord::Base
  has_many :items
end

class Item < ActiveRecord::Base
  has_many :urls
  belongs_to :group, touch: true
end

class Url < ActiveRecord::Base
  belongs_to :item
end

因此,我需要获取在group1中按项目名称排序的Ulrs列表.

类似的问题是如何获取按组名称排序的Url的完整列表,然后按项目名称排序.

使用sort_by方法创建几个简单循环不是问题,但是如果没有它们可能有任何优雅的方法吗？似乎.where和.order方法不支持关联.

在我的项目中,我必须将我的Rails应用程序连接到具有只读访问权限的旧MySQL服务器(v4).我在那里有第三方应用程序.不幸的是我无法改变这种情况.问题是,当我尝试连接那里时,我得到一个例外:

ActionController:Variable 'sql_mode' can't be set to the value of 'STRICT_ALL_TABLES'

这是我的database.yml文件

development:
  adapter: mysql2
  encoding: utf8
  database: td
  pool: 5
  username: user
  password: password
  host: 10.12.12.12

我可以使用任何数据库客户端连接到此数据库,但不能使用Rails应用程序.怎么解决？