Wordpress 附件字段保存格式为什么是这样的？

Question

在 wordpress 中附件跟文章保存在同一张表里，但是附件的所有信息是按照下面的格式保存，为什么是这种格式？另外这种格式是怎么来的？a:5:{s:5:"width";i:800;s:6:"height";i:600;s:4:"file";s:15:"laravelsite.png";s:5:"sizes";a:4:{s:9:"thumbnail";a:4:{s:4:"file";s:23:"laravelsite-150x150.png";s:5:"width";i:150;s:6:"height";i:150;s:9:"mime-type";s:9:"image/png";}s:6:"medium";a:4:{s:4:"file";s:23:"laravelsite-300x225.png";s:5:"width";i:300;s:6:"height";i:225;s:9:"mime-type";s:9:"image/png";}s:12:"medium_large";a:4:{s:4:"file";s:23:"laravelsite-768x576.png";s:5:"width";i:768;s:6:"height";i:576;s:9:"mime-type";s:9:"image/png";}s:14:"post-thumbnail";a:4:{s:4:"file";s:23:"laravelsite-800x510.png";s:5:"width";i:800;s:6:"height";i:510;s:9:"mime-type";s:9:"image/png";}}s:10:"image_meta";a:12:{s:8:"aperture";s:1:"0";s:6:"credit";s:0:"";s:6:"camera";s:0:"";s:7:"caption";s:0:"";s:17:"created_timestamp";s:1:"0";s:9:"copyright";s:0:"";s:12:"focal_length";s:1:"0";s:3:"iso";s:1:"0";s:13:"shutter_speed";s:1:"0";s:5:"title";s:0:"";s:11:"orientation";s:1:"0";s:8:"keywords";a:0:{}}}

Answer 1

数组序列化后的结果