mysql> create table zhangdan(ipn char(255),toipn char(255),starttime datetime,en dtime datetime,fee doublPRIMARY KEYe,primary key(ipn,toipn,starttime)); ERROR 1071: Specified key was too long. Max key length is 500 会有这个错误,怎么回事?
mysql> create table zhangdan(ipn char(255),toipn char(255),starttime datetime,en dtime datetime,fee double,primary key(ipn,toipn,starttime)); ERROR 1071: Specified key was too long. Max key length is 500 会有这个错误,怎么回事?
alter table 表名 add constraint 主键名 primary key (字段1,字段2,...);
mysql> create table zhangdan(ipn char(255) not null,toipn char(255) not null,sta rttime datetime,endtime datetime,fee double); Query OK, 0 rows affected (0.07 sec)mysql> alter table zhangdan add primary key(ipn,toipn,starttime); ERROR 1071: Specified key was too long. Max key length is 500 mysql> 这样也不行~~ 郁闷了~~~
ipn char(255),toipn char(255),starttime datetime提示很清楚啊!这三个字段的长度加起来起码520个字节,mysql提示你最长就500个字节!ERROR 1071: Specified key was too long. Max key length is 500
dtime datetime,fee doublPRIMARY KEYe,primary key(ipn,toipn,starttime));
ERROR 1071: Specified key was too long. Max key length is 500
会有这个错误,怎么回事?
dtime datetime,fee double,primary key(ipn,toipn,starttime));
ERROR 1071: Specified key was too long. Max key length is 500
会有这个错误,怎么回事?
rttime datetime,endtime datetime,fee double);
Query OK, 0 rows affected (0.07 sec)mysql> alter table zhangdan add primary key(ipn,toipn,starttime);
ERROR 1071: Specified key was too long. Max key length is 500
mysql>
这样也不行~~
郁闷了~~~