How to know if DB exists from within Rake task

问题:

How do i find out if the database exists from within a rake task?

that is, i'd like to do something like:

  task :drop_and_create => :environment do     Rails.env = "development"     if (db_exists?)       Rake::Task["db:drop"].invoke     end     Rake::Task["db:create"].invoke     #more stuff...   end 

how do i write the db_exists? condition?

回答1:

How about instead doing a begin/rescue:

task :drop_and_create => :environment do     Rails.env = "development"     if (db_exists?)     begin       Rake::Task["db:drop"].invoke      rescue Exception => e       logger.debug("Error:#{e}")     Rake::Task["db:create"].invoke     #more stuff...   end 

回答2:

  task :drop_and_create => :environment do     Rails.env = "development"     Rake::Task["db:reset"].invoke     #more stuff...   end 

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