Dataform (plugin)

By default permissions students can see all visible views and all entries and can edit their own entries. They cannot manage entries, where 'manage entries' means having permission to update and delete all entries in the activity. I'm still not sure what you are trying to acheive. If you want to prevent students from updating/deleting their own entries you can try preventing the mod/dataform:entryownupdate and mod/dataform:entryowndelete permissions from student role in the activity context. hth