PG ::错误：错误：关系schema_migrations的权限被拒绝
不知道为什么我遇到这个错误。 我正确设置了postgresql，只是运行了一个迁移，然后rake db：migrate，我得到了标题错误。
这是我的：
database.yml的
development: adapter: postgresql encoding: unicode database: my_blog_development pool: 5 username: my_blog password: test: adapter: postgresql encoding: unicode database: my_blog_test pool: 5 username: my_blog password: production: adapter: postgresql encoding: unicode database: my_blog_production pool: 5 username: my_blog password: 完整错误：
[my_blog]$rake db:migrate rake aborted! PG::Error: ERROR: permission denied for relation schema_migrations : SELECT "schema_migrations".* FROM "schema_migrations" /usr/local/rvm/gems/ruby-2.0.0-p195/gems/activerecord-4.0.0.rc1/lib/active_record/connection_adapters/postgresql_adapter.rb:739:in `exec' /usr/local/rvm/gems/ruby-2.0.0-p195/gems/activerecord-4.0.0.rc1/lib/active_record/connection_adapters/postgresql_adapter.rb:739:in `exec_no_cache' /usr/local/rvm/gems/ruby-2.0.0-p195/gems/activerecord-4.0.0.rc1/lib/active_record/connection_adapters/postgresql/database_statements.rb:138:in `block in exec_query' /usr/local/rvm/gems/ruby-2.0.0-p195/gems/activerecord-4.0.0.rc1/lib/active_record/connection_adapters/abstract_adapter.rb:425:in `block in log' /usr/local/rvm/gems/ruby-2.0.0-p195/gems/activesupport-4.0.0.rc1/lib/active_support/notifications/instrumenter.rb:20:in `instrument' /usr/local/rvm/gems/ruby-2.0.0-p195/gems/activerecord-4.0.0.rc1/lib/active_record/connection_adapters/abstract_adapter.rb:420:in `log' /usr/local/rvm/gems/ruby-2.0.0-p195/gems/activerecord-4.0.0.rc1/lib/active_record/connection_adapters/postgresql/database_statements.rb:137:in `exec_query' /usr/local/rvm/gems/ruby-2.0.0-p195/gems/activerecord-4.0.0.rc1/lib/active_record/connection_adapters/postgresql_adapter.rb:856:in `select' /usr/local/rvm/gems/ruby-2.0.0-p195/gems/activerecord-4.0.0.rc1/lib/active_record/connection_adapters/abstract/database_statements.rb:24:in `select_all' /usr/local/rvm/gems/ruby-2.0.0-p195/gems/activerecord-4.0.0.rc1/lib/active_record/connection_adapters/abstract/query_cache.rb:63:in `select_all' /usr/local/rvm/gems/ruby-2.0.0-p195/gems/activerecord-4.0.0.rc1/lib/active_record/querying.rb:36:in `find_by_sql' /usr/local/rvm/gems/ruby-2.0.0-p195/gems/activerecord-4.0.0.rc1/lib/active_record/relation.rb:561:in `exec_queries' /usr/local/rvm/gems/ruby-2.0.0-p195/gems/activerecord-4.0.0.rc1/lib/active_record/relation.rb:447:in `load' /usr/local/rvm/gems/ruby-2.0.0-p195/gems/activerecord-4.0.0.rc1/lib/active_record/relation.rb:196:in `to_a' /usr/local/rvm/gems/ruby-2.0.0-p195/gems/activerecord-4.0.0.rc1/lib/active_record/relation/delegation.rb:12:in `map' /usr/local/rvm/gems/ruby-2.0.0-p195/gems/activerecord-4.0.0.rc1/lib/active_record/migration.rb:770:in `get_all_versions' /usr/local/rvm/gems/ruby-2.0.0-p195/gems/activerecord-4.0.0.rc1/lib/active_record/migration.rb:928:in `migrated' /usr/local/rvm/gems/ruby-2.0.0-p195/gems/activerecord-4.0.0.rc1/lib/active_record/migration.rb:933:in `ran?' /usr/local/rvm/gems/ruby-2.0.0-p195/gems/activerecord-4.0.0.rc1/lib/active_record/migration.rb:910:in `block in runnable' /usr/local/rvm/gems/ruby-2.0.0-p195/gems/activerecord-4.0.0.rc1/lib/active_record/migration.rb:910:in `reject' /usr/local/rvm/gems/ruby-2.0.0-p195/gems/activerecord-4.0.0.rc1/lib/active_record/migration.rb:910:in `runnable' /usr/local/rvm/gems/ruby-2.0.0-p195/gems/activerecord-4.0.0.rc1/lib/active_record/migration.rb:887:in `migrate' /usr/local/rvm/gems/ruby-2.0.0-p195/gems/activerecord-4.0.0.rc1/lib/active_record/migration.rb:747:in `up' /usr/local/rvm/gems/ruby-2.0.0-p195/gems/activerecord-4.0.0.rc1/lib/active_record/migration.rb:725:in `migrate' /usr/local/rvm/gems/ruby-2.0.0-p195/gems/activerecord-4.0.0.rc1/lib/active_record/railties/databases.rake:42:in `block (2 levels) in ' /usr/local/rvm/gems/ruby-2.0.0-p195@global/gems/rake-10.0.4/lib/rake/task.rb:246:in `call' /usr/local/rvm/gems/ruby-2.0.0-p195@global/gems/rake-10.0.4/lib/rake/task.rb:246:in `block in execute' /usr/local/rvm/gems/ruby-2.0.0-p195@global/gems/rake-10.0.4/lib/rake/task.rb:241:in `each' /usr/local/rvm/gems/ruby-2.0.0-p195@global/gems/rake-10.0.4/lib/rake/task.rb:241:in `execute' /usr/local/rvm/gems/ruby-2.0.0-p195@global/gems/rake-10.0.4/lib/rake/task.rb:184:in `block in invoke_with_call_chain' /usr/local/rvm/gems/ruby-2.0.0-p195@global/gems/rake-10.0.4/lib/rake/task.rb:177:in `invoke_with_call_chain' /usr/local/rvm/gems/ruby-2.0.0-p195@global/gems/rake-10.0.4/lib/rake/task.rb:170:in `invoke' /usr/local/rvm/gems/ruby-2.0.0-p195@global/gems/rake-10.0.4/lib/rake/application.rb:143:in `invoke_task' /usr/local/rvm/gems/ruby-2.0.0-p195@global/gems/rake-10.0.4/lib/rake/application.rb:101:in `block (2 levels) in top_level' /usr/local/rvm/gems/ruby-2.0.0-p195@global/gems/rake-10.0.4/lib/rake/application.rb:101:in `each' /usr/local/rvm/gems/ruby-2.0.0-p195@global/gems/rake-10.0.4/lib/rake/application.rb:101:in `block in top_level' /usr/local/rvm/gems/ruby-2.0.0-p195@global/gems/rake-10.0.4/lib/rake/application.rb:110:in `run_with_threads' /usr/local/rvm/gems/ruby-2.0.0-p195@global/gems/rake-10.0.4/lib/rake/application.rb:95:in `top_level' /usr/local/rvm/gems/ruby-2.0.0-p195@global/gems/rake-10.0.4/lib/rake/application.rb:73:in `block in run' /usr/local/rvm/gems/ruby-2.0.0-p195@global/gems/rake-10.0.4/lib/rake/application.rb:160:in `standard_exception_handling' /usr/local/rvm/gems/ruby-2.0.0-p195@global/gems/rake-10.0.4/lib/rake/application.rb:70:in `run' /usr/local/rvm/gems/ruby-2.0.0-p195/bin/ruby_noexec_wrapper:14:in `eval' /usr/local/rvm/gems/ruby-2.0.0-p195/bin/ruby_noexec_wrapper:14:in `' Tasks: TOP => db:migrate
看起来你没有设置你的psql角色（或者用户，它们在postgres中非常相似）。 另外，我不确定postgres是否会抱怨有一个角色而没有登录密码（因为你必须告诉postgres允许用户/角色登录）
如果您以root数据库用户身份输入psql，则可以通过以下方式很好地设置角色：
create role my_blog with login password '' createdb;
另外，为了方便起见，如果你使用postgres，可能值得安装Postgres应用程序 ，它通常使得不需要密码进入管理员就可以轻松管理postgres，这样可以轻松查看/删除表格你会被困住。 这是一个很好的列表 ， 列出了从psql cli管理postgres的一些命令