PHP把数组转换为JSON字符串存到数据库中

<?php
/**PHP把数组转换为JSON字符串**/
$arr = [10,'Tom',true, '2015-10-15'];
//echo $arr;
echo json_encode($arr);//编码为JSON字符串
$arr = ['eid'=>10,'ename'=>'Tom','isMarried'=>true, 'birthday'=>'2015-10-15'];
//echo $arr;
echo json_encode($arr);//编码为JSON字符串
//结论：索引数组会被json_encode转换为JSON数组，关联数组会被json_encode转换为JSON对象
 ?>

结果如下
[10,"Tom",true,"2015-10-15"]
{"eid":10,"ename":"Tom","isMarried":true,"birthday":"2015-10-15"}

示例：

$order = ['eid'=>10,'ename'=>'Tom','isMarried'=>true, 'birthday'=>'2015-10-15'];
		$str = json_encode($order);
		$logOrder = [];
		$logOrder['orderId'] = 100;
		$logOrder['orderStatus'] = 0;
		$logOrder['logContent'] = "$str";
		$logOrder['logType'] = 0;
		$logOrder['logTime'] = time();
		Db::name('log_order')->insert($logOrder);