A monkey patch for Rails to fix SchemaDumper to not include table_name_prefix. Will probably be fixed in Rails soon, but needed this now. Based on PR: https://github.com/kennyj/rails/commit/211dcdeaa922c74ac20d274308fb5d41ad490194

active_record.rb

# config/initializers/active_record.rb
# Loads the monkey patch.

require 'active_record'
require 'active_record/schema_dumper'
require 'schema_dumper'

ActiveRecord::SchemaDumper.class_eval do
  include Nepco::SchemaDumper
end

schema.rb

# lib/schema_dumper.rb

module Nepco
  module SchemaDumper

    def self.included(base)
      base.alias_method_chain :table, :prefix_removed
      base.alias_method_chain :indexes, :prefix_removed
    end
    
    def table_with_prefix_removed(table, stream)
      columns = @connection.columns(table)
      begin
        tbl = StringIO.new

        # first dump primary key column
        if @connection.respond_to?(:pk_and_sequence_for)
          pk, _ = @connection.pk_and_sequence_for(table)
        elsif @connection.respond_to?(:primary_key)
          pk = @connection.primary_key(table)
        end

        tbl.print "  create_table #{remove_prefix_and_suffix(table).inspect}"
        if columns.detect { |c| c.name == pk }
          if pk != 'id'
            tbl.print %Q(, :primary_key => "#{pk}")
          end
        else
          tbl.print ", :id => false"
        end
        tbl.print ", :force => true"
        tbl.puts " do |t|"

        # then dump all non-primary key columns
        column_specs = columns.map do |column|
          raise StandardError, "Unknown type '#{column.sql_type}' for column '#{column.name}'" if @types[column.type].nil?
          next if column.name == pk
          spec = {}
          spec[:name]      = column.name.inspect

          # AR has an optimization which handles zero-scale decimals as integers. This
          # code ensures that the dumper still dumps the column as a decimal.
          spec[:type]      = if column.type == :integer && /^(numeric|decimal)/ =~ column.sql_type
                               'decimal'
                             else
                               column.type.to_s
                             end
          spec[:limit]     = column.limit.inspect if column.limit != @types[column.type][:limit] && spec[:type] != 'decimal'
          spec[:precision] = column.precision.inspect if column.precision
          spec[:scale]     = column.scale.inspect if column.scale
          spec[:null]      = 'false' unless column.null
          spec[:default]   = default_string(column.default) if column.has_default?
          (spec.keys - [:name, :type]).each{ |k| spec[k].insert(0, "#{k.inspect} => ")}
          spec
        end.compact

        # find all migration keys used in this table
        keys = [:name, :limit, :precision, :scale, :default, :null]

        # figure out the lengths for each column based on above keys
        lengths = keys.map { |key|
          column_specs.map { |spec|
            spec[key] ? spec[key].length + 2 : 0
          }.max
        }

        # the string we're going to sprintf our values against, with standardized column widths
        format_string = lengths.map{ |len| "%-#{len}s" }

        # find the max length for the 'type' column, which is special
        type_length = column_specs.map{ |column| column[:type].length }.max

        # add column type definition to our format string
        format_string.unshift "    t.%-#{type_length}s "

        format_string *= ''

        column_specs.each do |colspec|
          values = keys.zip(lengths).map{ |key, len| colspec.key?(key) ? colspec[key] + ", " : " " * len }
          values.unshift colspec[:type]
          tbl.print((format_string % values).gsub(/,\s*$/, ''))
          tbl.puts
        end

        tbl.puts "  end"
        tbl.puts

        indexes(table, tbl)

        tbl.rewind
        stream.print tbl.read
      rescue => e
        stream.puts "# Could not dump table #{table.inspect} because of following #{e.class}"
        stream.puts "#   #{e.message}"
        stream.puts
      end

      stream
    end

    def indexes_with_prefix_removed(table, stream)
      if (indexes = @connection.indexes(table)).any?
        add_index_statements = indexes.map do |index|
          statement_parts = [
            ('add_index ' + remove_prefix_and_suffix(index.table).inspect),
            index.columns.inspect,
            (':name => ' + index.name.inspect),
          ]
          statement_parts << ':unique => true' if index.unique

          index_lengths = (index.lengths || []).compact
          statement_parts << (':length => ' + Hash[index.columns.zip(index.lengths)].inspect) unless index_lengths.empty?

          index_orders = (index.orders || {})
          statement_parts << (':order => ' + index.orders.inspect) unless index_orders.empty?

          '  ' + statement_parts.join(', ')
        end

        stream.puts add_index_statements.sort.join("\n")
        stream.puts
      end
    end

    def remove_prefix_and_suffix(table)
      table.gsub(/^(#{ActiveRecord::Base.table_name_prefix})(.+)(#{ActiveRecord::Base.table_name_suffix})$/,  "\\2")
    end

  end
  
end