Create temp table in a for loop in php update#
I have a full login system which allows for users to login and manage their respective family members who are entering the show.Īt the moment I have an update statement which can be run by the Admin to reset all previous entrant contestant numbers from the previous years, I agree this is quite straight forward and consists of The only piece missing is how do you know who the active entrants are? You can end the loop when the number of affected rows is zero, meaning that the WHERE clause finding active entrants that have a zero entry number no longer matched any row(s). To assign new numbers, you would either a) have a form that submits the starting number, or b) if continuing the numbering for newly added entrants after you have already assigned some numbers, get the current MAX() value + 1, to be used and incremented in a loop where an UPDATE query, with an ORDER BY term, if you want the numbing to be applied to the rows in some particular order (date of registration, alphabetically by name, by class/division, …), and a LIMIT 1 term, assigns the current value to active entrants that have a zero entry number. To reset all the values to zero, just execute an UPDATE query setting the entry number column to a zero. Since this is apparently web based, do you currently have a user authentication/login system so that you can control who can cause these activities to be executed? If anyone can help please?īoth tasks are fairly simple.
Create temp table in a for loop in php how to#
It would loop until no entrants without an entry number is reached but how to construct this sort of looping array is where I need some advice and guidance. I believe a looping array which looks for each entrant with valid entries and then inserts the next number in the sequence to the entrant number. I have a script which resets all of the contestant numbers to 0 but how to get it to increment from a start number and update each entrant is where I am really stuck and I am looking for advice on the best way to do it. At the moment we conduct this operation manually however I am sure there is some way of doing but I am at a loss as where to start.
The entrant (contestant number) is a separate field against the Entrant Details.Īs you mention, conducting an update without a where statement is usually taboo and this is probably where I cannot find much reference material on how I can achieve this. Yes the table with the entrants has its own key which is used to relate to the family and to the actual classes entered. I need to be able to set the starting number and then assign the number to each active entrant as this years contestant number.Īny help and guidance in how I can achieve this will be appreciated. I am looking for a PHP/MySQL script I can use to insert a new contestant number which creates an incrementing number for each contestant who has entries this year. I am looking at creating a PHP/MySQL script which I can run which will set ALL entrants entry number (contestant number) to 0. However if they have entered the previous year they will still have the contestant number from the previous year. The online system I have built works well apart from two things I an stuck on and need some help please.Īt the moment each new entrant contestant number is set to 0. We usually have between 150 and 200 entrants over 190 classes in 12 divisions with around 1100 entries.Īgainst each entrant we need to create a unique entrant number as their contestant number for the coming year. We like to change the contestant number each year to avoid the possibility of cheating. The database holds user details with entrant details along with the divisions and classes each entrant wishes to enter for the coming year. For example, one could think that creating a temporary table one time and then loop on that table with cursors several times is an optimization – but that’s not the case.I have a MySQL database which holds the records for an annual Horticulture and Craft exhibition. But one should certainly be aware of this behavior. I am not complaining, and I don’t even know if this behavior can be changed. MySQL > SHOW STATUS LIKE 'Created_tmp_tables' SELECT id FROM t WHERE 0 LIMIT 0 FOR UPDATE Id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY SELECT FROM a temporary table: you are reading from a temporary tables, yes, but an internal temporary table is created anyway.Ī quick example: CREATE TEMPORARY TABLE t.FOR UPDATE: An exclusive lock is created, yes, but you still read data from a temporary table. However, in some cases one does not expect a temporary table to be created: In MariaDB and MySQL, cursors create a temporary table.ĭoes this statement deserve a whole blog post? Apparently not.
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