diff --git a/src/Orchard/Data/Migration/Interpreters/DefaultDataMigrationInterpreter.cs b/src/Orchard/Data/Migration/Interpreters/DefaultDataMigrationInterpreter.cs
index bb0da3d20..68b06d12d 100644
--- a/src/Orchard/Data/Migration/Interpreters/DefaultDataMigrationInterpreter.cs
+++ b/src/Orchard/Data/Migration/Interpreters/DefaultDataMigrationInterpreter.cs
@@ -270,7 +270,9 @@ namespace Orchard.Data.Migration.Interpreters {
 
             var builder = new StringBuilder();
 
-            builder.AppendFormat("alter table {0} drop constraint {1}", _dialectLazy.Value.QuoteForTableName(PrefixTableName(command.SrcTable)), PrefixTableName(command.Name));
+            builder.Append("alter table ")
++                .Append(_dialectLazy.Value.QuoteForTableName(PrefixTableName(command.SrcTable)))
++                .Append(_dialectLazy.Value.GetDropForeignKeyConstraintString(PrefixTableName(command.Name)));
             _sqlStatements.Add(builder.ToString());
 
             RunPendingStatements();
diff --git a/src/Orchard/Data/Migration/Interpreters/MySqlCommandInterpreter.cs b/src/Orchard/Data/Migration/Interpreters/MySqlCommandInterpreter.cs
index df3b1bd3a..33b9de478 100644
--- a/src/Orchard/Data/Migration/Interpreters/MySqlCommandInterpreter.cs
+++ b/src/Orchard/Data/Migration/Interpreters/MySqlCommandInterpreter.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Data;
 using System.Text;
 using NHibernate.Dialect;
@@ -34,6 +35,7 @@ namespace Orchard.Data.Migration.Interpreters {
             builder.AppendFormat("alter table {0} modify column {1} ",
                             _dialectLazy.Value.QuoteForTableName(PrefixTableName(command.TableName)),
                             _dialectLazy.Value.QuoteForColumnName(command.ColumnName));
+            var initLength = builder.Length;
 
             // type
             if (command.DbType != DbType.Object) {
@@ -46,13 +48,31 @@ namespace Orchard.Data.Migration.Interpreters {
             }
 
             // [default value]
+            var builder2 = new StringBuilder();
+
+            builder2.AppendFormat("alter table {0} alter column {1} ",
+                            _dialectLazy.Value.QuoteForTableName(PrefixTableName(command.TableName)),
+                            _dialectLazy.Value.QuoteForColumnName(command.ColumnName));
+            var initLength2 = builder2.Length;
+            
             if (command.Default != null) {
-                builder.Append(" set default ").Append(DefaultDataMigrationInterpreter.ConvertToSqlValue(command.Default)).Append(" ");
+                builder2.Append(" set default ").Append(DefaultDataMigrationInterpreter.ConvertToSqlValue(command.Default)).Append(" ");
             }
 
-            return new [] {
-                builder.ToString()
-            };
+            // result
+            var result = new List<string>();
+
+            if (builder.Length > initLength)
+            {
+                result.Add(builder.ToString());
+            }
+
+            if (builder2.Length > initLength2)
+            {
+                result.Add(builder2.ToString());
+            }
+
+            return result.ToArray();
         }
 
         private string PrefixTableName(string tableName) {