Read Infotype in Payroll Schema

Hi SAP Guys,

I'm calculating the tax base amount, I've requirement to reduce the basic salary by $4000 if the employee is married and additional $1000 per every child to reach the tax base. I know these information available in infotype 0002 'personal data' or infotype 0021 '' family Member/Dependents' and that I can use function P0021 or TABLE0021 to access, but what's about the syntax?

Regards,

Mohammad Aly