Product management system — 2

Need product management system.
Core Java and Sql.

Db tables
Product category(id, category)
Product(id, name, categoryid, originalQuantity, availableQuantity, priceperunit)
Sales(id,productid,quantity,totalamount,dateofsale)

All ok and fk established

GUI to add/edit categories,
add products, purchase or
sale where I can search, filter and purchase(add row into sales, update product to set new available quantity, validation before sale to make sure sale quantity is less or equal to a bailable quantity.