How to find Automatically PurchId Generate method and class

[SatheesKannan]

I created a new Purchase Order It Automatic Generated a PurchId . That PurhId How to generated automatically? Which Method and Class was Used and Where was the Insert method call…,

[kranthi]

it uses number seq form handler class.
\Classes\PurchTableType\numberSeqFormHandlerPurchId

\Classes\PurchTableType\formMethodDataSourceCreate