1、清空表：修复带外键无自增列的表清空报错

Tools/UI/wEmptyTable.cs

@@ -103,10 +103,13 @@ namespace Tools.UI
                     }
                     catch (Exception)
                     {
-                        //外键表，需要删除数据，然后重置自增主键
+                        //外键表，需要删除数据，如有自增列则重置自增
                         var foreign_sql = $@"
                             DELETE FROM {table}
-                            DBCC CHECKIDENT('{table}',RESEED,0)";
+                            IF EXISTS(SELECT 1 FROM sys.columns WHERE OBJECT_ID = OBJECT_ID('PurchaseDocTree') AND is_identity=1)
+                            BEGIN
+	                            DBCC CHECKIDENT('{table}',RESEED,0)
+                            END";
                         this._db.ExecNonSql(foreign_sql);
                         this.EmptyLog.Add(foreign_sql.Trim());
                     }