Updates

SqlTable.cs

@@ -7,7 +7,7 @@ namespace DbMigrate {
         public string TableName { get; set; }
         public string CreateTableSql { get; set; }
         public string OriginalSql { get; set; }
-        public Dictionary<string, string> Columns { get; set; }
+        public ColumnCollection Columns { get; set; }
         public Dictionary<string, string> Indexes { get; set; }
         public Dictionary<string, string> Triggers { get; set; }
 
@@ -24,7 +24,7 @@ namespace DbMigrate {
         }
 
         private void initTable() {
-            Columns = new Dictionary<string, string>();
+            Columns = new ColumnCollection();
             Indexes = new Dictionary<string, string>();
             Triggers = new Dictionary<string, string>();
             CreateTableSql = "";
@@ -54,15 +54,11 @@ namespace DbMigrate {
         }
 
         public string[] GetColumnNames() {
-            return Columns.Keys.ToArray();
-        }
-
-        public string[] GetColumns() {
-            return Columns.Values.ToArray();
+            return Columns.GetColumnNames();
         }
 
         public bool HasColumn(string columnName) {
-            return Columns.ContainsKey(columnName);
+            return Columns.Contains(columnName);
         }
 
         public string[] GetTriggerNames() {