我在Codeanywhere工作了一个新项目（我是Ruby的新手），但当我尝试使用def repeat(string, a = 1)
a.times.map { string }.join(" ")
end
时，我遇到了这个错误：
"rake db : migrate"在此之前我使用捆绑更新，之后什么也没有，当我放“rake-T”时，db Migartion正在执行任务，当我尝试使用--trace时，传递相同的内容。
我之前尝试使用rake aborted!
Don't know how to build task ':' (see --tasks)
/home/cabox/.rvm/gems/ruby-2.1.2/gems/rake-12.0.0/exe/rake:27:in `<top (required)>'
(See full trace by running task with --trace)
并且同样的事情发生了
`耙子流产！
rake db:migrate有谁知道如何解决这个问题？
在迁移文件中我有：
SyntaxError:
/home/cabox/workspace/blog/db/migrate/20170103233409_create_posts.rb:5: syntax error, unexpected ':'
/home/cabox/.rvm/gems/ruby-2.1.2/gems/activesupport-4.1.6/lib/active_support/dependencies.rb:247:in `require'
/home/cabox/.rvm/gems/ruby-2.1.2/gems/activesupport-4.1.6/lib/active_support/dependencies.rb:247:in `block in require'
/home/cabox/.rvm/gems/ruby-2.1.2/gems/activesupport-4.1.6/lib/active_support/dependencies.rb:232:in `load_dependency'
/home/cabox/.rvm/gems/ruby-2.1.2/gems/activesupport-4.1.6/lib/active_support/dependencies.rb:247:in `require'
/home/cabox/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.6/lib/active_record/migration.rb:761:in `load_migration'
/home/cabox/.rvm/gems/ruby-2.1.2/gems/activerecord- 4.1.6/lib/active_record/migration.rb:757:in `migration'
/home/cabox/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.6/lib/active_record/migration.rb:752:in `disable_ddl_transaction'
/home/cabox/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.6/lib/active_record/migration.rb:1044:in `use_transaction?'
/home/cabox/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.6/lib/active_record/migration.rb:1036:in `ddl_transaction'
/home/cabox/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.6/lib/active_record/migration.rb:990:in `execute_migration_in_transaction'
/home/cabox/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.6/lib/active_record/migration.rb:952:in `block in migrate'
/home/cabox/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.6/lib/active_record/migration.rb:948:in `each'
/home/cabox/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.6/lib/active_record/migration.rb:948:in `migrate'
/home/cabox/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.6/lib/active_record/migration.rb:807:in `up'
/home/cabox/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.6/lib/active_record/migration.rb:785:in `migrate'
/home/cabox/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.6/lib/active_record/railties/databases.rake:34:in `block (2 levels) in <top (required)>'
/home/cabox/.rvm/gems/ruby-2.1.2/gems/rake-12.0.0/exe/rake:27:in `<top (required)>'
Tasks: TOP => db:migrate
(See full trace by running task with --trace)` >
答案 0 :(得分：5)
我很确定发生了什么，当你输入它时，你正在那里插入一个空格。它必须是
rake db:migrate
不
rake db : migrate
当运行命令时出现拼写错误或其他类型的输入错误时，该错误消息非常常见。
您的迁移也有拼写错误，应该是
class CreatePosts < ActiveRecord::Migration
def change
create_table :posts do |t|
t.string :title
t.text :body
t.timestamps
end
end
end
答案 1 :(得分：1)
Rake是一个软件任务管理工具，与其他系统中的Make等类似
通用语法是
rake namesapce:task
在你的情况下，它是
rake db:migrate
答案 2 :(得分：-1)
如果要再次重建数据库，请尝试执行rake db:reset。它为你做了4件事
rake db:drop
rake db:create
rake db:migrate
rake db:seed