write/query in start_badi syntax

hi,

*START_BADI DAPP

DESTINATION_APP=u201DPLANNING5u201D

RENAME_DIM="P_ACCT=P2_ACCT"

ADD_DIM = "INTCO=I_NONE"

WRITE=OFF

QUERY=OFF

*END_BADI

in above syntax, what is significance of query(on/off) and write(on/off)? why recommend method off for write parameter?

thanks,