Rails, db_structure_dump, and Oracle

cwilliams — Thu, 30 Jun 2005 19:56:00 +0000

I use Ruby on Rails at work with an Oracle 10g database. The problem is that I have a couple new people who are supposed to begin helping with the project and would like to set up development databases. When I was using MySQL this was easy, I used the db_structure_dump task in rake and gave them the output file.

I tried to do the same with Oracle, but apparently the task and adapters aren’t set up for this. So after some looking around the web I came up with my own solution – to implement structure_dump in the oci_adapter. So if anyone needs this, here’s the quick and very dirty code. It could use some loving and cleaning before it gets submitted as a patch.

Add the following method to the OciAdapter class in active_record/connection_adapters/oci_adapter.rb:

def structure_dump
  select_all("select table_name from user_tables") .inject("") do |structure, table|
    string = "CREATE TABLE #{table.to_a.first.last} (\n "
    array = select_all("select column_name, data_type, data_length, data_precision,
       data_scale, data_default, nullable from all_tab_columns where table_name =
       '#{table.to_a.first.last}' order by column_id")
    
    array.collect! do |hash|
      tmp = "#{hash['column_name']} #{hash['data_type']}"	      
      if hash['data_type'] =='NUMBER' and !hash['data_precision'].nil?
        tmp << "(#{hash['data_precision'].to_i}"
        tmp << ",#{hash['data_scale'].to_i})" if !hash['data_scale'].nil?
        tmp << ')'
      elsif hash['data_type'].include?('CHAR')
        tmp << "(#{hash['data_length'].to_i})"  
      end	      
      tmp << " DEFAULT #{hash['data_default']}" if !hash['data_default'].nil?
      tmp << ' NOT NULL' if hash['nullable'] ="=" 'N'
      tmp	      
    end
    array.uniq!
    array.delete_if {|item| item.nil?}
    string << array.join(",\n ")
    string << ");\n\n"
    structure << string
  end
end

…And add “oci” to the case statement in the Rakefile:

desc "Dump the database structure to a SQL file"
task :db_structure_dump => :environment do
  abcs = ActiveRecord::Base.configurations
  case abcs[RAILS_ENV]["adapter"] 
    when "mysql", "oci"
      ActiveRecord::Base.establish_connection(abcs[RAILS_ENV])

"Rails, db_structure_dump, and Oracle" by Chris

Tue, 12 Jul 2005 12:53:23 +0000

It's been submitted as a patch now. Hopefully we'll see it in 1.0

"Rails, db_structure_dump, and Oracle" by Zsombor

Tue, 05 Jul 2005 07:59:05 +0000

Good work! How about submitting it as a a patch to rails trunk?

"Rails, db_structure_dump, and Oracle" by mcd

Fri, 01 Jul 2005 16:14:29 +0000

Good work. I'm in a learning path with Oracle and have been tracking Rails as a MVC framework so you post is a great tutorial for me w.r.t. Oracle SQL strategies AND a clue just how powerful Rails might be with such functionality embedded in the DB connector code. The Ruby syntax is just starting to become parsable for me. It looks clean and highly effective for a programmer that has mastered the tools. I'll be back for more insights and inspiration. Keep the code-based posts coming.

Late to the Party: Rails, db_structure_dump, and Oracle

Rails, db_structure_dump, and Oracle

"Rails, db_structure_dump, and Oracle" by Chris

"Rails, db_structure_dump, and Oracle" by Zsombor

"Rails, db_structure_dump, and Oracle" by mcd