How does one SELECT, INSERT, UPDATE and DELETE data from OraTCL?

Look at this example:

set connect scott/tiger@orcl
set lda [oralogon $connect]
set cur [oraopen $lda]
set sql {select tname from tab}

orasql $cur $sql
set row [orafetch $cur]
while {$oramsg(rc) == 0} {
	puts $row
	set row [orafetch $cur]
}

oraclose $cur
oralogoff $lda