I have a database containing messages with an "id" column in integer auto increment. Classical. But I would like to create a "visual" id based on this integer id. This is what I want :
A0001
A0002
[...]
A9999
B0001
B0002
[etc]
The ideal would be to generate automatically (in MYSQL) this messageId based on the integer id. I can also generate this id in PHP. But how ? The difficulty is that we have to check the last id in database to calculate what letter prefix the visual id.
Can you help me to generate this ? In MYSQL if it possible directly or in PHP?
You could use the following, but it is only good for numbers from 0 to 249999 (A0000 - Z9999)
select concat(char(ord('A')+round(ID / 10000)),ID % 10000) from ...
To convert back from a visual ID you can use the following:
select ord(VISUAL_ID)-ord('A')+mid(VISUAL_ID,2)
have you considered using hex? Why not to write OxA001 it's still integer if you do A001 then it's string and no AUTO INCREMENT is possible.
But if you want really to do it in mysql the only way would be using TRIGGERS.
You have 2 options you can create insert AFTER or BEFORE Insert statement and in this trigger you should update the value of ID to your value based on previous row. But I really recomend using hex.
You can read more about triggers here
You can create such ids using a before insert trigger to create the new value.
Basically you would look up the maximum value and then increment it, by doing something like:
(case when maxvalue like '%9999'
then concat(char(ascii(left(maxvalue, 1) + 1)), '0000')
else concat(left(maxvalue, 1), lpad(right(maxvalue, 4) + 1), 4, '0')
end);
However, I would discourage you from doing this and just set up a regular auto-increment column.
try this it may help you.
for ($i = 'A'; $i != 'AA'; $i++)
{
$prefix = $i;
$id = $prefix.sprintf("%03s",$suffix);
for ($j=1;$j<=5;$j++)
{
$res = "$id"."$j";
echo "$res"."<br>";
}
}
Related
Hello Every one,
I have an issue that is, I want to add an integer into a string for example I have two text field one is called series start and the other one is called series end now if user enters
FAHD1000001 into series start field
AND
FAHD1000100 into series end field
the algorithm should store 100 values into the database with increment into the each entry that is going to store into the database. i.e
FAHD1000001, FAHD1000002, FAHD1000003, ........., FAHD1000100
Is it possible to do so, if yes then how. Please help me
You have to do something like this but there is a loop hole if you have any numeric value in name like F1AHD00001 than it will not work
$str1 = $request['start'];
$str2 = $request['end'];
$startint=preg_replace("/[^0-9]/","",$str1);
$endint=preg_replace("/[^0-9]/","",$str2 );
$words = preg_replace('/[[:digit:]]/', '', $str1);
for($i=$startint;$i<$endint;$i++){
$newstring=$words.$i;
//Save this new String
}
there. I'm having a problem with creating arrays in certain conditions in php, i'll try to explain. Here's my code:
for ($i = 1; $i < $tamanho_array_afundamento; $i++) {
if ($array_afundamento[$i] - $array_afundamento[$i - 1] > 1) {
$a = $array_afundamento[$i - 1];
$con->query('CREATE TABLE IF NOT EXISTS afunda_$a
SELECT (L1_forma_tensao_max + L1_forma_tensao_min)/2 as L1_forma_tensao, (L2_forma_tensao_max + L2_forma_tensao_min)/2 as L2_forma_tensao, (L3_forma_tensao_max + L3_forma_tensao_min)/2 as L3_forma_tensao
FROM afundamento
WHERE id > $prevNum AND id < $a');
$tabelas_intervalos_afunda1 = ($con->query("SELECT * FROM afunda_$a");
while ($row = $tabelas_intervalos_afunda->fetch(PDO::FETCH_ASSOC)) {
$array_forma_onda_fase1_afund[] = $row['L1_forma_tensao'];
$array_forma_onda_fase2_afund[] = $row['L2_forma_tensao'];
$array_forma_onda_fase3_afund[] = $row['L3_forma_tensao'];
}
$prevNum = $a;
}
}
So as u can see, i have an if statement in a for loop, what i'm wishing to do is to create
one set of:
{
$array_forma_onda_fase1_afund[] = $row['L1_forma_tensao'];
$array_forma_onda_fase2_afund[] = $row['L2_forma_tensao'];
$array_forma_onda_fase3_afund[] = $row['L3_forma_tensao'];
}
every time the if statement is runned. I was trying replacing this in the original code:
{
$array_forma_onda_fase1_afund_$a[] = $row['L1_forma_tensao'];
$array_forma_onda_fase2_afund_$a[] = $row['L2_forma_tensao'];
$array_forma_onda_fase3_afund_$a[] = $row['L3_forma_tensao'];
}
so as $a is changed everytime the if statement is accessed, i could have a different set of these arrays for everytime the if statement is accessed, but php doesn't accept this and i wouldn't have a very good result, though if i can reach it i would be pleased.
But my goal is to get:
{
$array_forma_onda_fase1_afund_1[] = $row['L1_forma_tensao'];
$array_forma_onda_fase2_afund_1[] = $row['L2_forma_tensao'];
$array_forma_onda_fase3_afund_1[] = $row['L3_forma_tensao'];
}
{
$array_forma_onda_fase1_afund_2[] = $row['L1_forma_tensao'];
$array_forma_onda_fase2_afund_2[] = $row['L2_forma_tensao'];
$array_forma_onda_fase3_afund_2[] = $row['L3_forma_tensao'];
}
...
where the last number represents the array retrieved for the n-th time the if statement runned. Does someone have a tip for it?
Thanks in advance! Would appreciate any help.
EDIT
As asked, my real world terms is as follows:
I have a table from which i need to take all the data that is inside a given interval. BUT, there's a problem, my data is a sine function whose amplitude may change indefinite times (the data bank is entered by the user) and, when the amplitude goes inside that interval, i need to make some operations like getting the least value achieved while the data was inside that interval and some other parameters, for each interval separately, (That's why i created all those tables.) and count how many times it happpened.
So, in order to make one of the operations, i need an array with the data for each time the databank entered by the user goes in that interval (given by the limits of the create query.).
If i were not clear, just tell me please!
EDIT 2
Here's the image of part of the table i'm working with:
http://postimg.org/image/5vegnk043/
so, when the sine gets inside the interval i need, it can be seen by the L1_RMS column, who accuses it, so it's when i need to get the interval data until it gets outside the interval. But it may happens as many times as this table entered by the user brings it on and we need to bear in mind that i need all the intervals separately to deal with the data of each one.
Physics uh?
You can do what you wanted with the arrays, it's not pretty, but it's possible.
You can dynamically name your arrays with the _$a in the end, Variables variables, such as:
${"array_forma_onda_fase3_afund_" . $a}[] = "fisica é medo";
say if I wanted to give every user that registered on my site a unique id. It seems to me that if I wanted to do this I would have to: Create a random number for the id, check to see if that id already exists in the database, if it does exist then create another random number and send yet another query to see if that exists, and so on...
This could go on for ages. Apart from having an incrementing id, is there any decent way to do this?
The best way to do this is via the auto increment function, if you really don't want to use a function like so you could use uniqid();
Basically you it generates an unique id based on milliseconds, if you put in a kinda unique prefix in the function it will generate a very unique id.
echo uniqid('prefix');
This way you won't have to check after generating an id, if it already exists or not. You can be sure it is unique.
For more information check this url http://php.net/uniqid!
First of all, I agree with the comments. It's all overhead code, and if you're using it to make it look interesting you should really reconsider your priorities.
But, if you still need it; here's a little something:
function uid() {
mt_srand((double)microtime()*1000000);
$token = mt_rand(1, mt_getrandmax());
$uid = uniqid(md5($token), true);
if($uid != false && $uid != '' && $uid != NULL) {
$out = sha1($uid);
return $out;
} else {
return false;
}
}
Basically, it does a lot of random number generating to create a token for uniqueid, and then is sha's that. Probably overhead, but you can be sure that you never generate a double uid.
Fabian.
You can use the rand() function. It will generate a random number between two.
rand(0000,9999)
It will generate a number between 0 and 9999.
To check if it already exist:
$id = rand(0000,9999);
/* CREATE YOUR MYSQL CONNECTION */
$user_list = mysql_query("SELECT * FROM users");
while ($user = mysql_fetch_array($user_list))
{
if ($id == $user['id'])
{
echo('Already exist.');
}
else
{
/* YOUR CODE */
}
}
It's the way I did it...
If you have a string of 15 numbers you are looking at up to 999 trillion, I doubt it will run for "ages" considering there's almost 7 billion people on the planet.
Does the ID need to be numeric? By switching to alphabetic characters you will get a lot more entropy. A 6 digit number is 1,000,000 posibilities, a 6 character alphanumeric string is 2,176,782,336 possibilities. Make it mixed case alphanumeric and that jumps to 15,625,000,000.
Here's how I usually generate unique strings that are as short as possible:
$chars = 'abcdefghijklmnopqrstuvwrxyzABCDEFGHIJKLMNOPQRSTUVWRXYZ0123456789';
mt_srand((double)microtime()*1000000);
$id = '';
do {
$id .= $chars[mt_rand(0, strlen($chars) - 1)];
} while (isIdTaken($id));
var_dump($id);
You have to create a lot of items with this style of id, before you'll get to more than 3 or 4 characters.
I know it's late for this answer but the easiest solution is to generate random number and sure it will be unique 100% is
$uid = uniqid().date("Ymdhhis");
I have some columns in my table, descriptions column contains some information like;
a1b01,Value 1,2,1,60|a1b01,Value2,1,1,50|b203c,Value 1,0,2,20
with a SQL command, i need to update it.
In there, I'll use a PHP function for updating, if first and second parameters exist in current records (in description column) together.
Eg: if user wants to change the value of description that includes a1b01,Value 1 I'll execute a SQL command like that;
function do_action ($code,$value,$new1,$new2,$newresult) {
UPDATE the_table SET descriptions = REPLACE(descriptions, $code.','.$value.'*', $code.','.$value.','.$new1.','.$new2.','.$newresult)";
}
(star) indicates that, these part is unknown (This is why i need a regex)
My question is : how can i get
a1b01,Value 1,2,1,60|
part from below string
a1b01,Value 1,2,1,60|a1b01,Value2,1,1,50|b203c,Value 1,0,2,20
via regex, but a1b01 and Value 1 should be get as parameter.
I just want that; when I call do_action like that;
do_action ("a1b01","Value 1",2,3,25);
record will be : a1b01,Value 1,2,3,25|a1b01,Value2,1,1,50|b203c,Value 1,0,2,20(first part is updated...)
You don't necessarily need to use a regular expression to do this, you could use the explode function since it is all delimited
So you could do as follows:
$descriptionArray = explode('|', $descriptions); //creates array of the a1b01,Value 1,2,1,60 block
//then for each description explode on ,
for($i = 0; i < count($descriptionArray); $i++){
$parameters = explode(',', $descriptionArray[$i]);
do_action ($parameters[0],$parameters[1],$parameters[2],$parameters[3],$parameters[4]);
}
I have Sphinx Search installed as my search engine and I'm trying to add a few extra features to the search using setFilter() and SetSelect() which should allow me to do WHERE/AND clauses. But whenever I try a search, it returns no results instead of results.
Here is my sphinx.conf: http://pastebin.com/M6Kd71u0
And here's the PHP code:
require("sphinxapi.php");
$host = "localhost";
$port = 9312;
$index = "llgenre";
$select1 = "cartoon";
$label6 = "children";
$type = 4;
$limit = 20;
$ranker = SPH_RANK_PROXIMITY_BM25;
$mode = SPH_MATCH_ALL;
$sphinx = new SphinxClient();
$sphinx->setServer($host, $port);
$sphinx->setConnectTimeout(0);
$sphinx->setMatchMode($mode);
$sphinx->setRankingMode($ranker);
$sphinx->setSelect('*, select1="'.$select1.'" AND label6="'.$label6.'" AS mycond');
$sphinx->setFilter('mycond', array(1));
$res = $sphinx->query($type, $index);
die(var_dump($res));
How can I search by type = 4, filter by select1 with cartoon and finally on label6 with children?
I believe what you're attempting to do is to filter strings as attributes. Referring to the Sphinx FAQ, they outline the procedure
How do I filter, sort, or group by
string column without string
attributes?
You can do all of this, except for
precise arbtrary-length sorting over
several indexes.
To filter and group, you can replace
the string with an unique numeric ID.
Sometimes its possible to create a
lookup dictionary in the database (eg.
for fixed lists of cities or
countries), or even use an existing
one, replace strings with their IDs in
that dictionary, then filter and group
on that ID. If not, you can always
replace the string with its checksum,
eg. CRC32() or (any) 64 bits taken
from MD5() at indexing time (no need
to alter the tables!), store it using
sql_attr_uint or sql_attr_bigint
respectively, and then filter or group
on that checksum attribute. (Note that
there's a certain chance of CRC32()
collisions if you have millions of
strings but practically zero chance of
MD5() collisions.)
So, in my sphinx.conf, I might have the following...
sql_query = SELECT CRC32(string_field) AS `string_field` FROM `table`
sql_attr_uint = string_field
Then in PHP, I would apply a filter on the field like so...
$sphinx->SetFilter('string_field', array(crc32( 'filter_string' ));
--
Unfortunately, PHP has an annoying problem(bug?) when converting to crc32... something involving unsigned integers or something..
I use the following function to convert correctly
class Encode {
public static function crc32($val){
$checksum = crc32($val);
if($checksum < 0) $checksum += 4294967296;
return $checksum;
}
}
--
Be careful of character case! You may choose to convert the column to lower case while indexing eg.
sql_query = SELECT CRC32(LOWER(string_field)) AS `string_field` FROM `table`
and searching...
$sphinx->SetFilter('string_field', array(crc32(strtolower( 'Filter_String' )));