Updating a row in mysql Srpski chatroulette
The REPLACE statement first deletes the record with the same primary key and then inserts the new record.
This function returns the number of deleted records plus the number of inserted records. ON DUPLICATE KEY UPDATE" queries, the return value will be I see that when try to use mysql_affected_rows() with "mysql_pconnect(...)" without link indetifier as param in "mysql_affected_rows()" the result is allways -1.
It returns a simple line which shows the length of time taken to action the query, the status of the query (0= query not actioned, you can set this value for testing, 1=success qry executed successfully, -1= failed, there was a problem with the sql statement) the number of lines affected by that query and the sql statement itself.
I've found this invaluable when trying to tie down large amounts of updates to a table, using this you can easily see where a query was successfully executed and the number of rows are affected, or where there are problems and a statement has failed for example.
You have a REPLACE query on t1 followed by an INSERT query on t2 and expect the second query to fail if there's an attempted insert of a duplicate record.
If you access a column from the table to be updated in an expression, assignments are generally evaluated from left to right. If you omit the WHERE clause, all records in the table will be updated! The WHERE clause specifies which record(s) that should be updated.ON DUPLICATE KEY UPDATE" syntax, on PHP 5.3.29 and mysql_affected_rows() was returning either 2 for updated row, 1 for inserted new row, and also 0, which was not documented, evidently when nothing was inserted. calling mysql_affected_rows(null)is not the same that calling mysql_affected_rows()So, if you have a $link variable that could be null, you must writeif($link) $n=mysql_affected_rows($link);else $n=mysql_affected_rows(); SCENARIO1. You have table t2 linked to table t1 by a CASCADE ON DELETE foreign key.3.t2 has a UNIQUE key so that duplicate records are unacceptable.3.