Created the database class structure
Separated the database as a plugin and added a stock manager project
Test commit
All the table fields now have accessible values
Implemented the methods for creating the data tables
Fixed table creation query text code (now properly contains the comma separator) + minor refactoring
Implemented Insert-Delete-Update method chains for all the tables
Implemented SELECT queries for the Products table
Made the barcode field as UNIQUE
Fixed existing select queries in Products table
Added db data fetch queries and methods for some tables
Fixed barcode select function and added a new search query
Added class documentation and refactored some queries
Initial preparations for the stocks manager module
Added unit tests
Added libraries folder and fixed database code based on unit tests' results
Added more unit tests and fixed insert queries not working
Fixed update queries not working
Fixed delete query bug for the StockHistory data table
Changed the location for the libraries folder