>>>> 2013/03/15 12:43 -0300, Marcus Vinicius >>>> Does anyone knows the author of this:
http://grimoire.ca/mysql/choose-something-else Title: "Do Not Pass This Way Again" <<<<<<<< Not I --but, as to automatic type-conversion, I find me in agreement with the author. When I first began to use MySQL I was dismayed at all the automatic conversion, some of it decidedly unintuitive, and this one is a good example of particular badness: mysql> select 0 = 'banana'; +--------------+ | 0 = 'banana' | +--------------+ | 1 | +--------------+ 1 row in set, 1 warning (0.03 sec) mysql> show warnings; +---------+------+--------------------------------------------+ | Level | Code | Message | +---------+------+--------------------------------------------+ | Warning | 1292 | Truncated incorrect DOUBLE value: 'banana' | +---------+------+--------------------------------------------+ 1 row in set (0.00 sec) This definitly is an error to show, not let be a warning. All those 0-values on saving into the table, .... The developers seem deeply loath to report error. When the table is not transactional, yes, there is some reason for it, but a not transactional table is not a full partner in database. When the table is transactional, to report error is the way to go, although a big LOAD DATA be aborted, not to make the user learn about all those 0-values. He makes a point that had not come to me, that type-security somewhat depends on SQL_MODE, which belongs to the connection. It is, quite rightly, stored in saved program code, but not in any table. At least these affect table behavior, ALLOW_INVALID_DATES NO_AUTO_CREATE_USER (administrational security!) NO_AUTO_VALUE_ON_ZERO NO_ZERO_DATE NO_ZERO_IN_DATE PAD_CHAR_TO_FULL_LENGTH (well, maybe not this one) STRICT_ALL_TABLES STRICT_TRANS_TABLES , and they belong in the table, even as those that affect parsing & compiling belong in saved code, not only in the connection. MySQL s own types, ENUM and SET, which have both string & integer manifestation, are not well handled. Try this (version 5.5): create temporary table v (m set ('a','b')); insert into v value (1),(2),('a'),('b'),('b,a'),(null); select m,if( m is not null, m, 21) + 1 from v; select m,ifnull( m, 21) + 1 from v; -- no warning, either (and the numeric context is DOUBLE!) What about these? select m,if( m is not null, m, 21) from v; select m,ifnull( m, 21) from v; I feel that the numeric constant sets the context to numeric--the IF[NULL] s own context is indeterminate--, but not that happens. -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql
