think\Model::save PHP Method

    public function save($data = [], $where = [], $sequence = null)
    {
        if (!empty($data)) {
            // 数据自动验证
            if (!$this->validateData($data)) {
                return false;
            }
            // 数据对象赋值
            foreach ($data as $key => $value) {
                $this->setAttr($key, $value, $data);
            }
            if (!empty($where)) {
                $this->isUpdate = true;
            }
        }
        // 检测字段
        if (!empty($this->field)) {
            foreach ($this->data as $key => $val) {
                if (!in_array($key, $this->field)) {
                    unset($this->data[$key]);
                }
            }
        }
        // 数据自动完成
        $this->autoCompleteData($this->auto);
        // 自动写入更新时间
        if ($this->autoWriteTimestamp && $this->updateTime) {
            $this->setAttr($this->updateTime, null);
        }
        // 事件回调
        if (false === $this->trigger('before_write', $this)) {
            return false;
        }
        if ($this->isUpdate) {
            // 自动更新
            $this->autoCompleteData($this->update);
            // 事件回调
            if (false === $this->trigger('before_update', $this)) {
                return false;
            }
            // 去除没有更新的字段
            $data = [];
            foreach ($this->data as $key => $val) {
                if (in_array($key, $this->change) || $this->isPk($key)) {
                    $data[$key] = $val;
                }
            }
            if (!empty($this->readonly)) {
                // 只读字段不允许更新
                foreach ($this->readonly as $key => $field) {
                    if (isset($data[$field])) {
                        unset($data[$field]);
                    }
                }
            }
            if (empty($where) && !empty($this->updateWhere)) {
                $where = $this->updateWhere;
            }
            $pk = $this->getPk();
            if (is_string($pk) && isset($data[$pk])) {
                if (!isset($where[$pk])) {
                    unset($where);
                    $where[$pk] = $data[$pk];
                }
                unset($data[$pk]);
            }
            $result = $this->db()->where($where)->update($data);
            // 清空change
            $this->change = [];
            // 更新回调
            $this->trigger('after_update', $this);
        } else {
            // 自动写入
            $this->autoCompleteData($this->insert);
            // 自动写入创建时间
            if ($this->autoWriteTimestamp && $this->createTime) {
                $this->setAttr($this->createTime, null);
            }
            if (false === $this->trigger('before_insert', $this)) {
                return false;
            }
            $result = $this->db()->insert($this->data);
            // 获取自动增长主键
            if ($result) {
                $insertId = $this->db()->getLastInsID($sequence);
                $pk = $this->getPk();
                if (is_string($pk) && $insertId) {
                    $this->data[$pk] = $insertId;
                }
            }
            // 标记为更新
            $this->isUpdate = true;
            // 清空change
            $this->change = [];
            // 新增回调
            $this->trigger('after_insert', $this);
        }
        // 写入回调
        $this->trigger('after_write', $this);
        return $result;
    }

 public function add()
 {
     $this->startTrans();
     //>>1.检查用户提交过来的数据如果为默认值, 将其他的默认去掉
     if (isset($this->data['is_default'])) {
         $result = $this->where(array('member_id' => UID))->setField('is_default', 0);
         if ($result === false) {
             $this->rollback();
             return false;
         }
     }
     if (!empty($this->data['id'])) {
         $id = $this->data['id'];
         //>>1.更新
         $result = parent::save();
         //使用this->data中的数据进行更新
         if ($result === false) {
             $this->rollback();
             return false;
         }
     } else {
         //>>2.保存
         $id = parent::add();
         //
         if ($id === false) {
             $this->rollback();
             return false;
         }
     }
     $this->commit();
     //>>3.根据id再从数据库中获取一行数据
     $row = $this->find($id);
     //>>4.返回这一行数据
     return $row;
 }