怎么将这段插入数据的代码改成修改数据的代码?
sinto="insert into userinfo (username,password,question,ask,name,email,phone,fax,address,sex,age,education,employment,occupation,income,companyname,homepage,province,companysize)"
sinto=sinto&"values ('"
sinto=sinto&username&"','"
sinto=sinto&password&"','"
sinto=sinto&question&"','"
sinto=sinto&ask&"','"
sinto=sinto&name&"','"
sinto=sinto&email&"','"
sinto=sinto&phone&"','"
sinto=sinto&fax&"','"
sinto=sinto&address&"','"
sinto=sinto&sex&"','"
sinto=sinto&age&"','"
sinto=sinto&education&"','"
sinto=sinto&employment&"','"
sinto=sinto&occupation&"','"
sinto=sinto&income&"','"
sinto=sinto&companyname&"','"
sinto=sinto&homepage&"','"
sinto=sinto&province&"','"
sinto=sinto&companysize&"')"
my.execute(sinto) %>