add a deletion strategy for sequel

database_cleaner.gemspec

@@ -87,6 +87,7 @@ Gem::Specification.new do |s|
     "lib/database_cleaner/redis/base.rb",
     "lib/database_cleaner/redis/truncation.rb",
     "lib/database_cleaner/sequel/base.rb",
+    "lib/database_cleaner/sequel/deletion.rb",
     "lib/database_cleaner/sequel/transaction.rb",
     "lib/database_cleaner/sequel/truncation.rb",
     "spec/database_cleaner/active_record/base_spec.rb",

lib/database_cleaner/sequel/base.rb

@@ -2,7 +2,7 @@ require 'database_cleaner/generic/base'
 module DatabaseCleaner
   module Sequel
     def self.available_strategies
-      %w[truncation transaction]
+      %w[truncation transaction deletion]
     end
 
     module Base
@@ -14,7 +14,7 @@ module DatabaseCleaner
 
       def db
         return @db if @db && @db != :default
-        raise "As you have more than one active sequel database you have to specify the one to use manually!" if ::Sequel::DATABASES.count > 1 
+        raise "As you have more than one active sequel database you have to specify the one to use manually!" if ::Sequel::DATABASES.count > 1
         ::Sequel::DATABASES.first || :default
       end
     end

lib/database_cleaner/sequel/deletion.rb

@@ -0,0 +1,33 @@
+require "database_cleaner/sequel/base"
+require "database_cleaner/generic/truncation"
+require "database_cleaner/sequel/truncation"
+
+module DatabaseCleaner::Sequel
+  class Deletion < Truncation
+    def clean
+      db.transaction do
+        case db.database_type
+        when :postgres
+          db.run "SET CONSTRAINTS ALL DEFERRED"
+          tables_to_truncate(db).each do |table|
+            db.run "ALTER TABLE #{::Sequel.lit(table)} DISABLE TRIGGER ALL"
+          end
+        when :mysql
+          db.run "SET FOREIGN_KEY_CHECKS = 0"
+        end
+        each_table do |db, table|
+          db[table].delete
+        end
+      end
+    ensure
+      case db.database_type
+      when :postgres
+        tables_to_truncate(db).each do |table|
+          db.run "ALTER TABLE #{::Sequel.lit(table)} ENABLE TRIGGER ALL"
+        end
+      when :mysql
+        db.run "SET FOREIGN_KEY_CHECKS = 1"
+      end
+    end
+  end
+end