how to update data by using id in php & mysql i update but data not updated data should be deleted why :     [enter image description here][1]

I share one image that image contain program. i try to update data by using that program but data is not updated in the table but it shows that data is updated successfully but data is not updated. when i try to execute that program  data is deleted.then how can i update data.


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[enter image description here][enter image description here][1]


  [1]: https://i.stack.imgur.com/BJK8r.png