在Ruby on Rails框架中,rails db:create命令用于创建开发和测试数据库。如果这个命令成功执行,但随后出现了错误,可能是由以下几个原因造成的: 基础概念 数据库创建:rails db:create会根据config/database.yml文件中的配置来创建开发和测试数据库。 错误类型:可能出现的错误包括但不限于数据库连接错误、权限问题、数据...
rails db:create错误 今天用rails连接mysql后,rake db:create出现这个错误 Couldn't create database for {"adapter"=>"mysql2", "encoding"=>"utf8", "pool"=>5, "username"=>"root", "password"=>nil, "socket"=>"/var/run/mysqld/mysqld.sock", "database"=>"myblog_test"} rake aborted! G...
rake db:create # Create the database defined in config/database.yml for the current RAILS_ENV rake db:create:all # Create all the local databases defined in config/database.yml rake db:drop # Drops the database for the current RAILS_ENV rake db:drop:all # Drops all the local databases...
rake db:schema:dump # Create a db/schema.rb file that can be portably used against any DB supported by AR rake db:schema:load # Load a schema.rb file into the database rake db:sessions:clear # Clear the sessions table rake db:sessions:create # Creates a sessions migration for use wit...
原因是少安装了东西或者环境变量不正确 执行: $gem install execjs $gem install therubyracer $sudo apt-get install nodejs 正在读取软件包列表... 完成 正在分析软件包的依赖关系树 正在读取状态信息... 完成 将会安装下列额外的软件包: libc-ares2 libev4 libv8-3.8.9.20 ...
本指南只针对 Discourse 开发环境的配置，如果你需要在生产环境中安装 Discourse ，请访问页面：Install ...
Previously, `rails db:create`, `rails db:drop`, and `rails db:migrate` were the only rails tasks that could operate on a single database. For example: ``` rails db:create rails db:create:primary rails db:create:animals rails db:drop rails db:drop:primary rails db:drop:an...
rails db:migrate//迁移(暂时理解为生成一张对应的据表) 在rubymine自带的终端 开启调试 bin/rails c 输入: 创建 # 直接创建一条数据在对应的表中,并且保存模型名.create(字段名:'...',...)# new 方法实例化一个新对象,但不保存:# 例子:user=User.newuser.name="David"user.occupation="Code Artist"#...
DB=catalog rails db:create Create a migration DB=catalog rails generate migration add_name_to_products Run migrations DB=catalog rails db:migrate Rollback DB=catalog rails db:rollback Models Also works for models DB=catalog rails generate model Product ...
# 生成迁移文件rails g migration CreateJoinTableCustomerProduct customer product# 迁移rails db:migrate# 版本回滚rails db:rollbackstep=1 这里在学习的时候,遇到一个东西,困惑了半天,那就是外键,外键用于两个表之间一对多关系。一个用户能写多篇文章,所以 article model belongs_to,而 user model has_many。