JSON保存在数据库中并使用JQuery加载

I create a huge JSON-Object and save it in my database. But when I load the "string" and echo it in PHP, I can't access the JSON Object in JQuery. Do I have to consider something if I want to save my JSON Object in a MySQL Database (when I just create the Array and then echo it with "echo json_encode($arr);" it works fine, but I need to save the Object for caching).I create a huge JSON-Object and save it in my d