How to do math operations with model fields or expressions in Agile Toolkit
问题 atk4.2.1 I have this model: class Model_Cargo extends Model_Table { public $table='cargo'; function init(){ parent::init(); $this->hasOne('Alumno'); $this->hasOne('Plan'); $this->addField('fecha')->type('date'); $this->addField('fechaCreacion')->type('date'); $this->addField('fechaVencimiento')->type('date'); $this->addField('name'); $this->addField('monto')->type('money'); $this->addField('cancelado')->type('boolean')->defaultValue(false); $this->hasMany('Abono'); $this->addExpression(