构建自个儿的PHP框架-实现Model类(3)

程序员文章站 2022-05-11 16:50:36

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构建自己的PHP框架--实现Model类(3)

在之前的博客中，我们实现并完善了Model类的findOne方法，下面我们来实现其中的其他方法。

先来看findAll方法，这个方法和findOne很相似。

    public static function findOne($condition = null)    {        $sql = 'select * from ' . static::tableName();        $params = [];        // 判空        if (!empty($condition)) {            $sql .= ' where ';            $params = array_values($condition);            $keys = [];            foreach ($condition as $key => $value) {                array_push($keys, "$key = ?");            }            $sql .= implode(' and ', $keys);        }        $stmt = static::getDb()->prepare($sql);        $rs = $stmt->execute($params);        $models = [];        if ($rs) {            // 直接获取出所有符合条件的            $rows = $stmt->fetchAll(PDO::FETCH_ASSOC);            foreach ($rows as $row) {                if (!empty($row)) {                    $model = new static();                    foreach ($row as $rowKey => $rowValue) {                        $model->$rowKey = $rowValue;                    }                    array_push($models, $model);                }            }        }        return null;    }

你会发现有findOne和findAll方法很相似，明显可以将公共的部分抽出来，然后我们就多了如下两个方法：

    /**     * Build a sql where part     * @param mixed $condition a set of column values     * @return string     */    public static function buildWhere($condition, $params = null)    {        if (is_null($params)) {            $params = [];        }        $where = '';        if (!empty($condition)) {            $where .= ' where ';            $keys = [];            foreach ($condition as $key => $value) {                array_push($keys, "$key = ?");                array_push($params, $value);            }            $where .= implode(' and ', $keys);        }        return [$where, $params];    }    /**     * Convert array to model     * @param  mixed $row the row data from database     */    public static function arr2Model($row)    {        $model = new static();        foreach ($row as $rowKey => $rowValue) {            $model->$rowKey = $rowValue;        }        return $model;    }

分别是构建sql中where部分的方法和将查找到的Array转换成Model的方法。大家会奇怪第一个方法中为什么需要params参数和返回值，其实这个为了之后的updateAll方法的使用。其实这个地方跟适合使用引用传值。

这样我们的findOne和findAll就便成了如下内容：

    /**     * Returns a single model instance by a primary key or an array of column values.     *     * ```php     * // find the first customer whose age is 30 and whose status is 1     * $customer = Customer::findOne(['age' => 30, 'status' => 1]);     * ```     *     * @param mixed $condition a set of column values     * @return static|null Model instance matching the condition, or null if nothing matches.     */    public static function findOne($condition = null)    {        list($where, $params) = static::buildWhere($condition);        $sql = 'select * from ' . static::tableName() . $where;        $stmt = static::getDb()->prepare($sql);        $rs = $stmt->execute($params);        if ($rs) {            $row = $stmt->fetch(PDO::FETCH_ASSOC);            if (!empty($row)) {                return static::arr2Model($row);            }        }        return null;    }    /**     * Returns a list of models that match the specified primary key value(s) or a set of column values.     *     *  ```php     * // find customers whose age is 30 and whose status is 1     * $customers = Customer::findAll(['age' => 30, 'status' => 1]);     * ```     *     * @param mixed $condition a set of column values     * @return array an array of Model instance, or an empty array if nothing matches.     */    public static function findAll($condition = null)    {        list($where, $params) = static::buildWhere($condition);        $sql = 'select * from ' . static::tableName() . $where;        $stmt = static::getDb()->prepare($sql);        $rs = $stmt->execute($params);        $models = [];        if ($rs) {            $rows = $stmt->fetchAll(PDO::FETCH_ASSOC);            foreach ($rows as $row) {                if (!empty($row)) {                    $model = static::arr2Model($row);                    array_push($models, $model);                }            }        }        return $models;    }

剩下的updateAll/deleteAll/insert/update和delete方法就不一一详细说明了，直接给出代码。其基本思想都是一致的，都是按照规则拼接SQL语句。

    /**     * Updates models using the provided attribute values and conditions.     * For example, to change the status to be 2 for all customers whose status is 1:     *     * ~~~     * Customer::updateAll(['status' => 1], ['status' => '2']);     * ~~~     *     * @param array $attributes attribute values (name-value pairs) to be saved for the model.     * @param array $condition the condition that matches the models that should get updated.     * An empty condition will match all models.     * @return integer the number of rows updated     */    public static function updateAll($condition, $attributes)    {        $sql = 'update ' . static::tableName();        $params = [];        if (!empty($attributes)) {            $sql .= ' set ';            $params = array_values($attributes);            $keys = [];            foreach ($attributes as $key => $value) {                array_push($keys, "$key = ?");            }            $sql .= implode(' , ', $keys);        }        list($where, $params) = static::buildWhere($condition, $params);        $sql .= $where;        $stmt = static::getDb()->prepare($sql);        $execResult = $stmt->execute($params);        if ($execResult) {            // 获取更新的行数            $execResult = $stmt->rowCount();        }        return $execResult;    }    /**     * Deletes models using the provided conditions.     * WARNING: If you do not specify any condition, this method will delete ALL rows in the table.     *     * For example, to delete all customers whose status is 3:     *     * ~~~     * Customer::deleteAll([status = 3]);     * ~~~     *     * @param array $condition the condition that matches the models that should get deleted.     * An empty condition will match all models.     * @return integer the number of rows deleted     */    public static function deleteAll($condition)    {        list($where, $params) = static::buildWhere($condition);        $sql = 'delete from ' . static::tableName() . $where;        $stmt = static::getDb()->prepare($sql);        $execResult = $stmt->execute($params);        if ($execResult) {            // 获取删除的行数            $execResult = $stmt->rowCount();        }        return $execResult;    }    /**     * Inserts the model into the database using the attribute values of this record.     *     * Usage example:     *     * ```php     * $customer = new Customer;     * $customer->name = $name;     * $customer->email = $email;     * $customer->insert();     * ```     *     * @return boolean whether the model is inserted successfully.     */    public function insert()    {        $sql = 'insert into ' . static::tableName();        $params = [];        $keys = [];        foreach ($this as $key => $value) {            array_push($keys, $key);            array_push($params, $value);        }        // 构建由？组成的数组，其个数与参数相等数相同        $holders = array_fill(0, count($keys), '?');        $sql .= ' (' . implode(' , ', $keys) . ') values ( ' . implode(' , ', $holders) . ')';        $stmt = static::getDb()->prepare($sql);        $execResult = $stmt->execute($params);        // 将一些自增值赋回Model中        $primaryKeys = static::primaryKey();        foreach ($primaryKeys as $name) {            // Get the primary key            $lastId = static::getDb()->lastInsertId($name);            $this->$name = (int) $lastId;        }        return $execResult;    }    /**     * Saves the changes to this model into the database.     *     * Usage example:     *     * ```php     * $customer = Customer::findOne(['id' => $id]);     * $customer->name = $name;     * $customer->email = $email;     * $customer->update();     * ```     *     * @return integer|boolean the number of rows affected.     * Note that it is possible that the number of rows affected is 0, even though the     * update execution is successful.     */    public function update()    {        $primaryKeys = static::primaryKey();        $condition = [];        foreach ($primaryKeys as $name) {            $condition[$name] = isset($this->$name) ? $this->$name : null;        }        $attributes = [];        foreach ($this as $key => $value) {            if (!in_array($key, $primaryKeys, true)) {                $attributes[$key] = $value;            }        }        return static::updateAll($condition, $attributes) !== false;    }    /**     * Deletes the model from the database.     *     * @return integer|boolean the number of rows deleted.     * Note that it is possible that the number of rows deleted is 0, even though the deletion execution is successful.     */    public function delete()    {        $primaryKeys = static::primaryKey();        $condition = [];        foreach ($primaryKeys as $name) {            $condition[$name] = isset($this->$name) ? $this->$name : null;        }        return static::deleteAll($condition) !== false;    }