int 数字类型
class int(object):
"""
int(x=0) -> int or long
int(x, base=10) -> int or long
Convert a number or string to an integer, or return 0 if no arguments
are given. If x is floating point, the conversion truncates towards zero.
mysql字符类型默认是不区分大小写的，即select * from t where name=’AAA’与=’aaa’没区别，以下是测试的例子
(rootlocalhost)[hello]> create table test1(id int, name varchar(10));
(rootlocalhost)[hello]> insert into test1 values(1,'aaa'),(2,'AAA'),(3,'bbb'),(4,'BbB');
(rootlocalh
