oracle 中update select 和连接字符串配合使用

update SYS_MDL_DIMSET_ACXMModel b
set f_Srccont =
(select SYS_MDL_DIMSET.f_Srccont || 'useInnrDataSet=0;'
from sinojzxm.SYS_MDL_DIMSET_ACXMModel a
where a.rowid = b.rowid)
where cst_id = 'ZYXMYE0000002'