[PDO]②①--主键查询

 /** 根据主键查找记录
     * @param $tabName
     * @param $priId
     * @param string $fields
     * @return mixed
     */
    public static function findById($tabName, $priId, $fields = '*')
    {
        $sql = 'SELECT %s FROM %s WHERE id=%d;';
        return self::getRow(sprintf($sql, self::parseFields($fields), $tabName, $priId));
    }

    /**
     * 解析字段
     * @param $fields
     * @return string
     */
    public static function parseFields($fields)
    {
        if (is_array($fields)) {
            array_walk($fields, array('PdoMySQL', 'addSpecilChar'));
            $fieldsStr = implode(',', $fields);
        } else if (is_string($fields) && !empty($fields)) {
            if (strpos($fields, '^') === false) {
                //0==false 0:position
                $fields = explode(',', $fields);
                array_walk($fields, array('PdoMySQL', 'addSpecilChar'));
                $fieldsStr = implode(',', $fields);
            } else {
                $fieldsStr = $fields;
            }
        } else {
            $fieldsStr = '*';
        }
        return $fieldsStr;

    }

    /**
     * 通过反引号引用字段
     * @param $value
     */
    public static function addSpecilChar(&$value)
    {
        if ($value == '*' || strpos($value, '.') !== false || strpos($value, '^') !== false) {
            //不用做处理

        } elseif (strpos($value, '^') === false) {
            //$value = '^' . trim($value) . '^';
            $value = '' . trim($value) . '';
        }

    }

PdoMYSQL.class.php

 DB_HOST,
                'username' => DB_USER,
                'password' => DB_PWD,
                'database' => DB_NAME,
                'hostport' => DB_PORT,
                'dsn' => DB_TYPE . ":host=" . DB_HOST . ";dbname=" . DB_NAME);
        }
        if (empty($dbConfig['hostname']))
            self::throw_exception('没有定义数据库配置，请先定义');
        self::$config = $dbConfig;
        if (empty(self::$config['params']))
            self::$config['params'] = array();
        if (!isset(self::$link)) {
            $configs = self::$config;
            if (self::$pconnect) {
                //开启长连接，添加到配置数组中
                $configs['params'][constant("PDO::ATTR_PERSISTENT")] = true;
            }
            try {
                self::$link = new PDO($configs['dsn'], $configs['username'], $configs['password'], $configs['params']);
            } catch (PDOException $e) {
                self::throw_exception($e->getMessage());
            }
            if (!self::$link) {
                self::throw_exception('PDO连接错误');
                return false;
            }
            self::$link->exec('SET NAMES ' . DB_CHARSET);
            self::$dbVersion = self::$link->getAttribute(constant("PDO::ATTR_SERVER_VERSION"));
            self::$connected = true;
            unset($configs);
        }
    }

    /**得到所有记录
     * @param null $sql
     * @return mixed
     */
    public static function getAll($sql = null)
    {
        if ($sql != null) {
            self::query($sql);
        }
        $result = self::$PDOStatement->fetchAll(constant("PDO::FETCH_ASSOC"));
        return $result;
    }

    /**
     * 得到结果集的一条记录
     * @param null $sql
     * @return mixed
     */
    public static function getRow($sql = null)
    {
        if ($sql != null) {
            self::query($sql);
        }
        $result = self::$PDOStatement->fetch(constant("PDO::FETCH_ASSOC"));
        return $result;
    }


    /** 根据主键查找记录
     * @param $tabName
     * @param $priId
     * @param string $fields
     * @return mixed
     */
    public static function findById($tabName, $priId, $fields = '*')
    {
        $sql = 'SELECT %s FROM %s WHERE id=%d;';
        return self::getRow(sprintf($sql, self::parseFields($fields), $tabName, $priId));
    }

    /**
     * 解析字段
     * @param $fields
     * @return string
     */
    public static function parseFields($fields)
    {
        if (is_array($fields)) {
            array_walk($fields, array('PdoMySQL', 'addSpecilChar'));
            $fieldsStr = implode(',', $fields);
        } else if (is_string($fields) && !empty($fields)) {
            if (strpos($fields, '^') === false) {
                //0==false 0:position
                $fields = explode(',', $fields);
                array_walk($fields, array('PdoMySQL', 'addSpecilChar'));
                $fieldsStr = implode(',', $fields);
            } else {
                $fieldsStr = $fields;
            }
        } else {
            $fieldsStr = '*';
        }
        return $fieldsStr;

    }

    /**
     * 通过反引号引用字段
     * @param $value
     */
    public static function addSpecilChar(&$value)
    {
        if ($value == '*' || strpos($value, '.') !== false || strpos($value, '^') !== false) {
            //不用做处理

        } elseif (strpos($value, '^') === false) {
            //$value = '^' . trim($value) . '^';
            $value = '' . trim($value) . '';
        }

    }


    /**执行增删改操作，返回受影响的记录的条数
     * @param null $sql
     * @return bool|int
     */
    public static function execute($sql = null)
    {
        $link = self::$link;
        if (!$link) return false;
        self::$queryStr = $sql;
        if (!empty(self::$PDOStatement)) self::free();
        $result = $link->exec(self::$queryStr);
        self::haveErrorThrowException();
        if ($result) {
            self::$lastInsertId = $link->lastInsertId();
            self::$numRows = $result;
            return self::$numRows;
        } else {
            return false;
        }
    }


    /**
     * 释放结果集
     */
    public static function free()
    {
        self::$PDOStatement = null;
    }

    public static function query($sql = '')
    {
        $link = self::$link;
        if (!$link) return false;
        //判断之前是否有结果集，如果有，释放结果集
        if (!empty(self::$PDOStatement)) self::free();
        self::$queryStr = $sql;
        self::$PDOStatement = $link->prepare(self::$queryStr);
        $res = self::$PDOStatement->execute();
        self::haveErrorThrowException();
        return $res;
    }

    public static function haveErrorThrowException()
    {
        $obj = empty(self::$PDOStatement) ? self::$link : self::$PDOStatement;
        $arrError = $obj->errorInfo();
        /**
         * Array
         * (
         * [0] => 42S02
         * [1] => 1146
         * [2] => Table 'test.user1' doesn't exist
         * )
         */
//        print_r($arrError);
        if ($arrError[0] != '00000') {
            self::$error = 'SQLSTATE ' . $arrError[0] . 'SQL Error: ' . $arrError[2] . '
Error SQL: ' . self::$queryStr;
            self::throw_exception(self::$error);
            return false;
        }
        if (self::$queryStr == '') {
            self::throw_exception('没有执行SQL语句');
            return false;
        }
    }

    /**
     * 自定义错误处理
     * @param $errMsg
     */
    public
    static function throw_exception($errMsg)
    {
        echo '

        ' . $errMsg . '
';
    }

}

require_once 'config.php';
$PdoMySQL = new PdoMYSQL();

//$tabName = 'user';
//$priId = '3';
//print_r($PdoMySQL::findById($tabName, $priId));

$tabName = 'user';
$priId = '14';
//$fields = 'username,email';
$fields = array('username', 'email');
print_r($PdoMySQL::findById($tabName, $priId, $fields));

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