以下猴子补丁解决了模式转储器（Rails 3.2）的 FULLTEXT 索引问题和数据库引擎选项。你可以把它放在config/initializers/（例如schema_dumper_monkeypatch.rb）：
module ActiveRecord
class SchemaDumper
def table(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"
# Add table engine
res = @connection.execute "SHOW TABLE STATUS LIKE '#{table}'"
engine = res.first[res.fields.index("Engine")] rescue nil
tbl.print ", :options => 'ENGINE=#{engine}'" if engine
res = nil # Free the result
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/].any? { |e| e.match(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] & column_specs.map{ |k| k.keys }.flatten
# 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(table, stream)
if (indexes = @connection.indexes(table)).any?
add_index_statements = indexes.map do |index|
if index.name =~ /fulltext/i
" execute \"CREATE FULLTEXT INDEX #{index.name} ON #{index.table} (#{index.columns.join(',')})\""
elsif index.name =~ /spatial/i
" execute \"CREATE SPATIAL INDEX #{index.name} ON #{index.table} (#{index.columns.join(',')})\""
else
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
end
stream.puts add_index_statements.sort.join("\n")
stream.puts
end
end
end
end