C# Application with multiple .xsd datasets data is removed

Question

I am trying to build a way for me to keep up with serial numbers for multiple items. 1. Accessories, 2 Household, 3 Pistol, 4 Rifle. Pictures of the xsd tables

my starting form simply has 4 buttons Pistol, Rifle, Gun Accessories, and Household items. Clicking on these buttons opens the form. If i click on Household Items, and fill out the form and save, the data saves correctly, and i can go out and back in to this form to view the data, however, if i then click on Pistol and input my information there, and save, then go back into Household Items, the information has been removed. How do i use multiple data sets and retain the date even if the application is closed then reopened?