Normally, errors occurs for data-change statements (such as
INSERT
or
UPDATE
) that would violate
primary-key, unique-key, or foreign-key constraints. If you
are using a transactional storage engine such as
InnoDB
, MySQL automatically rolls back the
statement. If you are using a nontransactional storage engine,
MySQL stops processing the statement at the row for which the
error occurred and leaves any remaining rows unprocessed.
MySQL supports an IGNORE
keyword for
INSERT
,
UPDATE
, and so forth. If you
use it, MySQL ignores primary-key or unique-key violations and
continues processing with the next row. See the section for
the statement that you are using (Section 12.2.5, “INSERT
Syntax”,
Section 12.2.12, “UPDATE
Syntax”, and so forth).
You can get information about the number of rows actually
inserted or updated with the
mysql_info()
C API function.
You can also use the SHOW
WARNINGS
statement. See
Section 21.9.3.35, “mysql_info()
”, and
Section 12.4.5.41, “SHOW WARNINGS
Syntax”.
Currently, only InnoDB
tables support
foreign keys. See
Section 13.6.4.4, “FOREIGN KEY
Constraints”.
User Comments
Quick Example of ignoring a unique key
Here is our table:
CREATE TABLE `file_names` (
`id` int(11) NOT NULL auto_increment,
`file_name` text NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `file_name` (`file_name`(200))
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=4 ;
Here is our query
INSERT IGNORE INTO `its_streamingdata`.`file_names` (`id` ,
`file_name`) VALUES (NULL , 'a'), (NULL , 'a')
The table now contains one row with a filename of 'a'
HTH
Hamy
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