protected function isExists(array $value)
    {

        // validate fields by exist in tables

        foreach ($value as $table => $fields) {

            // load model metaData

            if ($this->isModel($table) === true) {
                $model = (new Manager())->load($table, new $table);

                // check fields of table

                $this->validColumns($model->getModelsMetaData(), $fields, $table, $model);

                // setup clear used tables
                $columnDefines = (new $table)->getReadConnection()->describeColumns($model->getSource());

                // add using tables with model alias
                $this->fields['tables'][$model->getSource()] = $table;

                // checking columns & fields

                foreach ($columnDefines as $column) {

                    if (in_array($column->getName(), $fields) === true) {
                        $this->validTypes($column);

                        // add column to table collection
                        $this->fields[$this->cast][$model->getSource()][$column->getName()] = $column->getType();
                    }
                }
            }
        }

        return true;
    }