Syncing with iTunes - Song Deleted from iPhone stays in iTunes PC Library

[M_W]

Up until now I've always manually managed the songs on my iPhone by dragging them from my PC library to my iPhone. I figured I'd give the sync feature a try, thinking that it would be nice to have any changes I make on my iPhone reflect to my PC, and vice-versa. I enabled syncing for my entire music library, hit the sync button, and everything copied over. I decided to test it out by deleting a song on my iPhone and seeing if it would be deleted from my PC. The song stayed on my PC, so I tried it the other way around by deleting a song from my PC. This time, the song I deleted from my PC got deleted from my iPhone.
So it appears that deleted songs only sync from PC to iPhone.

I don't understand the reasoning behind this.
Is this how it's supposed to work, or is there a setting I can turn on to allow full syncing both ways?

 

[Shirasaki]

Yup. That’s how iTunes syncing works: one way trip, Apple ‘s favorite. Been there long time ago.

Some third party apps in Mac and windows could achieve two-way syncing. One of them I used before is iExplorer. But two-way syncing is a bit buggy. I only use that app to fix my broken iTunes library on device.

 

[M_W]

Yup. That’s how iTunes syncing works: one way trip, Apple ‘s favorite. Been there long time ago.

Some third party apps in Mac and windows could achieve two-way syncing. One of them I used before is iExplorer. But two-way syncing is a bit buggy. I only use that app to fix my broken iTunes library on device.

Ah, oh well. Thanks for the reply.

 

[BrianBaughn]

It's like that so that you can control the storage usage on your iOS device without deleting the "master" copy from your PC's iTunes library.

If you have an Apple Music subscription you can control what is downloaded to your device as well as what is in your library on all devices.