Delete record from table via shell script

Question

I have the following code

echo "Please enter your Roll No"
 read -r roll
res_var=`sqlplus -s username/password << EOF
BEGIN
delete from stud_table where roll_no = '$roll'
COMMIT;
END;
/
EOF
`

I wish to delete a record when the user input roll no
Is my above code correct? Iam not getting any error but records are not getting deleted either

Answer 1

1. I think you don't need read - r. Use just read roll
2. Make sure roll_no is not a varachar. if yes, add single quotes to $roll