Accrual entries journal line type

Hi

The accounting entry for a receipt in purchasing is  expense(charge)  DB to Accrual CR .

When i query the event class Period End Accrual i see for  both the seeded journal line types Accrual and charge SIDE is mentioned as 'DEBIT'

Should JTL charge not be DEBIT and Accrual CREDIT ?

In this case as both the JLT are of DEBIT type how is the system generating accounting entry as Expense DB to Accrual CR?

Thanks
AJ