backend-api/app/extra/basic/Dao.php

<?php

namespace app\extra\basic;

abstract class Dao
{
    /**
     * @var Model 模型单例实例
     */
    protected $modelInstance = null;

    /**
     * 获取当前模型
     * @return string
     */
    abstract protected function setModel(): string;

    /**
     * 获取模型（单例，避免重复实例化）
     * @return Model
     */
    protected function getModel()
    {
        if ($this->modelInstance === null) {
            $modelClass = $this->setModel();
            $this->modelInstance = new $modelClass();
        }
        return $this->modelInstance;
    }

    /**
     * 根据条件获取一条数据
     * @param array $where
     * @param string|null $field
     * @param array $with
     * @return array|Model|null
     * @throws \think\db\exception\DataNotFoundException
     * @throws \think\db\exception\DbException
     * @throws \think\db\exception\ModelNotFoundException
     */
    public function getOne(array $where, ?string $field = '*')
    {
        return $this->getModel()->where($where)->field($field)->findOrEmpty();
    }

    /**
     * @param array $where
     * @param string $field
     */
    public function selectWhere(array $where, string $field = '*')
    {
        return $this->getModel()->where($where)->field($field)->select();
    }

    /**
     * 读取数据条数
     * @param array $where
     * @return int
     */
    public function count(array $where = []): int
    {
        return $this->getModel()->where($where)->count();
    }


    /**
     * 更新数据
     * @param int|string|array $id
     * @param array $data
     * @param string|null $key
     * @return mixed
     */
    public function update($id, array $data, ?string $key = null)
    {
        if (is_array($id)) {
            $where = $id;
        } else {
            $where = [is_null($key) ? $this->getModel()->getPk() : $key => $id];
        }
        $data['updated_at'] = date('Y-m-d H:i:s');
        return $this->getModel()->where($where)->update($data);
    }

    /**
     * 插入数据
     * @param array $data
     * @return mixed
     */
    public function save(array $data)
    {
        $data['created_at'] = date('Y-m-d H:i:s');
        return $this->getModel()->create($data);
    }

    /**
     * 插入数据
     * @param array $data
     * @return mixed
     */
    public function saveAll(array $data)
    {
        $data['created_at'] = date('Y-m-d H:i:s');
        return $this->getModel()->insertAll($data);
    }

    /**
     * 求和
     * @param array $where
     * @param string $field
     * @param bool $search
     * @return float
     */
    public function sum(array $where, string $field)
    {
        return $this->getModel()->where($where)->sum($field);
    }

    /**
     * 某个字段累加某个数值
     * @param string $field
     * @param int $num
     */
    public function incField(array $where, string $field, $num = 1)
    {
        return $this->getModel()->where($where)->inc($field, $num)->update();
    }

    /**
     * 某个字段累加某个数值
     * @param string $field
     * @param int $num
     */
    public function decField(array $where, string $field, $num = 1)
    {
        return $this->getModel()->where($where)->dec($field, $num)->update();
    }
}