I am an app where users can search for other users within a specified height range. In Swift I have a UIPickerView with the following values:
seekingminHeightdata = ["Under 4'","4'1","4'2","4'3","4'4","4'5","4'6","4'7","4'8","4'9","4'10","4'11","5'","5'1","5'2","5'3","5'4","5'5","5'6","5'7","5'8","5'9","5'10","5'11","6'","6'1","6'2","6'3","6'4","6'5","6'6","6'7","6'8","6'9","6'10","6'11","7'","Above 7'"]
Once a user makes a selection that value is passed to a php file and later stored in the MySQL database. My problem is I have to run a search on this field that would be something like this:
select * from users WHERE minheight < $minheight and maxheight >= $maxheight
I don't know how to perform the search with the ' in the values. I know if I convert it to inches it will simplify what I want to do, but with the special characters in Swift UIPickerView I'm stumped. Any help?
You can create a procedure and use it to compare two values. Here is an example that shows you can split a string using ' character and compare 2 parts of it.
CREATE FUNCTION SPLIT_STRING(str VARCHAR(255), delim VARCHAR(12), pos INT)
RETURNS VARCHAR(255)
RETURN REPLACE(SUBSTRING(SUBSTRING_INDEX(str, delim, pos),
LENGTH(SUBSTRING_INDEX(str, delim, pos-1)) + 1),
delim, '');
SELECT #a1:= SPLIT_STRING("4'1", "'", 1);
SELECT #a2:= SPLIT_STRING("4'1", "'", 2);
SELECT #b1:= SPLIT_STRING("3'2", "'", 1);
SELECT #b1:= SPLIT_STRING("3'2", "'", 2);
SELECT #a1 > #b1;
SELECT #a2 > #b2;
You can use this procedure in your code and it depends on what you need.
You need to separate the value shown in a picker view from the value sent to your PHP script. As you stated, all of the calculations will be much simpler on the PHP side if you use inches (or centimeters or any other single unit value).
You also need to consider that most locales are metric and you should show users heights in centimeters, not feet/inches.
I suggest you keep an array of numbers, say in inches, from 48 to 84. Use that as your data. Then for display in the picker view you can convert that number to an appropriate display string such as feet/inches or cm.
When the user picks a row in the picker, you use the index to get the number from the array and pass that number to the PHP script where is can easily compare the numbers.
Related
I'm using PHP 7 with Phalcon PHP and I'm trying to create a method to generate a booking number. Here is my current method :
public function generateNumber($company_code) {
// Build the prefix : COMPANY20190820
$prefix = $company_code . date('Ymd');
// It's like SELECT count(*) FROM bookings WHERE number LIKE 'COMPANY20190820%'
$counter = Bookings::count(array(
"number LIKE :number:",
"bind" => array('number' => $prefix.'%')
));
// Concat prefix with bookings counter with str_pad
// COMPANY20190820 + 005 (if 4 bookings in DB)
$booking_number = $prefix . str_pad($counter + 1, 3, 0, STR_PAD_LEFT);
// Return COMPANY20190820005
return $booking_number;
}
So I have a problem because sometime I have to delete 1 or multiple bookings so I can get :
COMPANY20190820001
COMPANY20190820002
COMPANY20190820005
COMPANY20190820006
COMPANY20190820007
And I need to add after the last in my DB so here 007, because I can get duplicated booking number if I count like that.
So how can I do to take the last and increment according the last booking number of the current day ?
You need to rethink what you want to do here as it will never work that way.
As I see it you have at least two options:
Use an auto-increment id and use that in combination with the prefix
Use a random fairly unique string (e.g. UUID4)
You should never manually try to get the current maximum id as that may and most likely will at some point result in race conditions and brittle code as a result of that.
So I found a solution, maybe there is a better way to do that but my function works now:
public function generateNumber($company_code) {
// Build the prefix : COMPANY20190820
$prefix = $company_code . date('Ymd');
// Get the last booking with the today prefix
// e.g : COMPANY20190820005
$last_booking = Bookings::maximum(array(
"column" => "number",
"number LIKE :number:",
"bind" => array('number' => $prefix.'%')
));
// Get the last number by removing the prefix (e.g 005)
$last_number = str_replace($prefix, "", $last_booking);
// trim left 0 if exist to get only the current number
// cast to in to increment my counter (e.g 5 + 1 = 6)
$counter = intval(ltrim($last_number, "0")) + 1;
// Concat prefix + counter with pad 006
$booking_number = $prefix . str_pad($counter, 3, 0, STR_PAD_LEFT);
// Return COMPANY20190820006
return $booking_number;
}
I reckon that the use case you describe does not justify the hassle of writing a custom sequence generator in PHP. Additionally, in a scenario where booking deletion is expected to happen, ID reusing feels more a bug than a feature, so your system should store a permanent counter to avoid reusing, making it less simple. Don't take me wrong, it can be done and it isn't rocket science, but it's time and energy you don't need to spend.
Your database engine surely has a native tool to generate autoincremented primary keys, with varying names and implementations (SQL Server has identity, Oracle has sequences and identity, MySQL has auto_increment...). Use that instead.
Keep internal data and user display separated. More specifically, don't use the latter to regenerate the former. Your COMPANY20190820007 example is trivial to compose from individual fields, either in PHP:
$booking_number = sprintf('%s%s%03d',
$company_code,
$booking_date->format('Ymd'),
$booking_id
);
... or in SQL:
-- This is MySQL dialect, other engines use their own variations
SELECT CONCAT(company_code, DATE_FORMAT(booking_date, '%Y%m%d'), LPAD(booking_id, 3, '0')) AS booking_number
FROM ...
You can (and probably should) save the resulting booking_number, but you cannot use it as source for further calculations. It's exactly the same case as dates: don't need to store dates in plain English in order to eventually display them to the end-user and you definitively don't want to parse English dates back to actual dates in order to do anything else beyond printing.
You also mention the possibility of generating long pure-digit identifiers, as Bookings.com does. There're many ways to do it and we can't know which one they use, but you may want to considering generating a numeric hash out of your auto-incremented PK via integer obfuscation.
you could split your database field in two parts, so you hold the prefix and the counter separately.
then, you simply select the highest counter for your desired prefix and increment that one.
if you can't change the table structure, you could alternatively order by the id descendingly and select the first. then you can extract its counter manually. keep in mind you should pad the numbers then, or you get #9 even if #10 exists.
if padding is not an option, you can direct the database to replace your prefix. that way, you can cast the remaining string to a number and let the database sort - this will cost some performance, though, so keep the amount of records low.
I'm working on a project using the pages in php / mysql and html; I have a table that contains the data for calls made from a PBX and save the number called, the source, date, time, etc ... what I want to do is to search within this table all the phone numbers that have the first 4 digits equal to those that pass through the query, only that i have no idea how to pull off only the 4-digit or at least how to make a control character by character of the value contained in the field. I tell you now that the field is a varchar. Thank you in advance :)
To do that in MySQL query, either
SELECT *
FROM <tablename>
WHERE LEFT(<column>, 4) = "<4 digits>"
or
SELECT *
FROM <tablename>
WHERE <column> LIKE "<4 digits>%"
or in the PHP side :
if (strpos($column,'<4 digit>') !== false) {
echo 'true';
}
Use this, to get substring
SELECT aut_name,
RIGHT(aut_name,7)
FROM author
WHERE country='UK';
See more at: http://www.w3resource.com/mysql/string-functions/mysql-right-function.php#sthash.xKNwZeki.dpuf
I suggest this solution:
$variableWhereYoustoreTheFourDigits="1234"; //Use whatever you have in your code to set the value.
$result =$mysqli->query("SELECT number FROM yourtable where number LIKE \"$variableWhereYoustoreTheFourDigits%\");
I have a database table with various fields involving jobs done on ships including a field named created which uses DATE format. The result i want to achieve is to have a unique reference number for each job. The format i want to use for this reference number is:
example : Lets say the date of the job is 23/11/2013 like today. Then the number would be 1311/1 the next job 1311/2 and goes on. If the month changes and the date of the next job is for example 15/12/2013 the refence number i would like to have if its the first job of the month is 1312/1.
So the two first digits of my reference number would show the year,the next two the month and the number after the slash i would like it to be an auto_increment number that will reset each month.My code so far is :
$job_num = 1;
foreach($random as $rand) {
$vak = $rand->created;
$gas = $rand->id;
$vak1 = substr($vak, 2, 2);
$vak2 = substr($vak, 5, -3);
$vak3 = substr($vak, 8, 10);
if(date(j) > 1) {
echo $vak1.$vak2.'/'.$job_num.'<br>';
$job_num++;
} else {
$job_num = 1;
echo $vak1.$vak2.'/'.$job_num.'<br>';
$job_num++;
}
}
So as u can see i want to achieve all this inside a foreach statement. And although the above code kinda works,the porblem i have is that at the 1st of any month in other words when date(j) = 1 if i insert more than one job in my database the $job_num variable resets as many times as the jobs i have inserted resulting in identical refence numbers.
I am really new in programming and php so if anyone could help me solve this, i would really appreciate it.
Thanks in advance:)
You can't do this with the auto-increment mechanism if you use InnoDB, which is MySQL's default storage engine.
You can do it with the MyISAM storage engine, but you really shouldn't use MyISAM, for many reasons.
So you'll have to assign the repeating numbers yourself. This means you have to lock the table while you check what is the current maximum number for the given month, then insert a new row with the next higher number.
If that seems like it would impair concurrent access to the table, you're right. Keep in mind that MyISAM does a table-lock during insert/update/delete of any row.
If you can use the MyISAM engine, you can get this behavior without procedural code.
create table demo (
yr_mo integer not null,
id integer auto_increment,
other_columns char(1) default 'x',
primary key (yr_mo, id)
) engine=MyISAM;
insert into demo (yr_mo) values (1311);
insert into demo (yr_mo) values (1311);
insert into demo (yr_mo) values (1311);
insert into demo (yr_mo) values (1311);
insert into demo (yr_mo) values (1312);
The last INSERT statement starts a new month.
Now if you look at the autoincrement values the MyISAM engine assigned . . .
select * from demo;
YR_MO ID OTHER_COLUMNS
--
1311 1 x
1311 2 x
1311 3 x
1311 4 x
1312 1 x
This is MyISAM's documented behavior; look for "MyISAM Notes".
If you want the form yymm/n for presentation, use something like this.
select concat(yr_mo, '/', id) as cat_key
from demo;
I have a VBScript that I`m converting to PHP, I hae some part that I don`t understand and don`t know the output of ... Also if possible, provide me with a similar method in HTML/PHP
TextBox1.Value = 1#
txtTurnoverIncl = TextBox1
Format(CDbl(txtTurnoverExcl.Text) * _
CDbl(txtRoyalty.Text) / 100, "#,##0.00")
If txtTurnoverExcl.Text <> "" Then
Format(Round(.Text * 14 / 114, 2), "#,##0.00")
TextBox1 = Now()
TextBox3 = Date
TextBox4 = Format(MyDate, "dddd")
And this function:
Private Function SumCashUp() As Double
Dim i As Long
Dim tmp As Double
For i = 10 To 12
With Me.Controls("TextBox" & i)
If IsNumeric(.Text) Then
tmp = tmp + CDbl(.Text)
End If
End With
Next i
SumCashUp = tmp
End Function
I guess thats all.
TextBox1.Value = 1# - Assign the value 1 in format Double to the textbox control. (thanks MikeD)
txtTurnoverIncl = TextBox1 - Assigning reference to the control TextBox to variable called txtTurnoverIncl
CDbl(txtTurnoverExcl.Text) - Convert the text inside the textbox txtTurnoverExcl to double i.e. numeric value with decimal point e.g. 2.6 - this is useful if you want to perform mathematical operations on the value for example.
Format(..., "#,##0.00") - Format number to look like this: 2.60 or 8.25 i.e. with two digits after decimal point.
Round(.Text * 14 / 114, 2) - The .Text means you're inside With (somecontrol) block, so it's actually somecontrol.Text i.e. taking the Text of the control. Round function will round the number for example Round(662.791, 2) will return 662.79 and Round(662.796, 2) will return 662.8
Now() - Returns the current date and time on the machine where the code is executing
Date or Date() - Like Now() but only with the date, time will be 00:00:00
Format(MyDate, "dddd") - Get name of the day of week of MyDate, according to the Culture on the machine. For example for Hebrew culture it will return יום שלישי for English culture it will return Tuesday. In general, Format() given date and string will Format the date according to the string e.g. Format(Now(), "dd/MM/yyyy") will return 14/12/2010
The last function returns the sum of the values of the textboxes named "Textbox10", "Textbox11", and "Textbox12" in a pretty complicated way. I guess in PHP you would do something like this (assuming you are POSTing a form):
function sumCashUp() {
return (double) $_POST['Textbox10'] + (double) $_POST['Textbox11'] + (double) $_POST['Textbox12'];
}
first of all it would be better to analyze what the whole thing is doing (semantically) rather than looking at sequences of code. So the remainder of this post is a bit speculative ....
There are a couple of textboxes displayed on the screen
TextBox1 ... initialized with value 1(double), later containing current time (now()) (imho a sin in itself - brrrr - hope there is good business logic explanation for this)
TextBox3 ... initialized with the current date
TextBox4 ... initialized with "something we don't know" - hopefully a date (MyDate), and formated as Weekday ("dddd")
TextBox10 - TextBox12 ... seem to be used to calculate a variable SumCashUp
we have some more variables which may be textboxes as well (as sometimes we see a .Text added in the code)
txtTurnoverIncl
txtTurnoverExcl
txtRoyalty
SumCashUp
and a code fragment that calculates a 14% margin from a Gross (*14/114), rounds and formats the result ... and we have no clue about where this result is used. We can speculate that it may be another form field (because of .Text) - maybe txtRoyalty - but we don't know.
Basically all the code fragments are about putting values into textboxes displayed on the screen and/or using the values of that text boxes to compute something (like the SumCashUp or a 14% GM).
So I guess the path to the solution must be
get the source layout of textboxes
understand the business logic
create a HTML page containing a form with similar objects (textboxes, a submit button, etc.)
write PHP code that implements the business logic - most probably as a reaction to a POST event triggered by a Submit button
You already received a couple of code fragments, but one needs to put this into a greater context, otherwise the code blocks won't help.
I'm programming a script using PHP and MySQL and I want to get a
unique id (consisting of a string: capitals and small
letters with numbers) like: gHYtUUi5b.
I found many functions in PHP that can generate such numbers but I'm afraid about how to ensure the id is unique!
UPDATE: uuid is long, I mean such id like: (P5Dc) an 11 alphanumeric char.
EDIT: This answer has been flagged for being dangerous in the context of destroying a database. Do NOT use this code to generate unique ids in databases!
I use UUID() to create a unique value.
example:
insert into Companies (CompanyID, CompanyName) Values(UUID(), "TestUUID");
You may like the way that we do it. I wanted a reversible unique code that looked "random" -a fairly common problem.
We take an input number such as 1,942.
Left pad it into a string: "0000001942"
Put the last two digits onto the front: "4200000019"
Convert that into a number: 4,200,000,019
We now have a number that varies wildly between calls and is guaranteed to be less than 10,000,000,000. Not a bad start.
Convert that number to a Base 34 string: "2oevc0b"
Replace any zeros with 'y' and any ones with 'z': "2oevcyb"
Upshift: "2OEVCYB"
The reason for choosing base 34 is so that we don't worry about 0/O and 1/l collisions. Now you have a short random-looking key that you can use to look up a LONG database identifier.
A programmatic way can be to:
add a UNIQUE INDEX to the field
generate a random string in PHP
loop in PHP ( while( ! DO_THE_INSERT ) )
generate another string
Note:
This can be dirty, but has the advantage to be DBMS-agnostic
Even if you choose to use a DBMS specific unique ID generator function (UUID, etc)
it is a best practice to assure the field HAS to be UNIQUE, using the index
the loop is statistically not executed at all, it is entered only on insert failure
If you use MySQL with version higher than 5.7.4, you can use the newly added RANDOM_BYTES function:
SELECT TO_BASE64(RANDOM_BYTES(16));
This will result in a random string such as GgwEvafNLWQ3+ockEST00A==.
How you generate the unique_ids is a useful question - but you seem to be making a counter productive assumption about when you generate them!
My point is that you do not need to generate these unique id's at the time of creating your rows, because they are essentially independent of the data being inserted.
What I do is pre-generate unique id's for future use, that way I can take my own sweet time and absolutely guarantee they are unique, and there's no processing to be done at the time of the insert.
For example I have an orders table with order_id in it. This id is generated on the fly when the user enters the order, incrementally 1,2,3 etc forever. The user does not need to see this internal id.
Then I have another table - unique_ids with (order_id, unique_id). I have a routine that runs every night which pre-loads this table with enough unique_id rows to more than cover the orders that might be inserted in the next 24 hours. (If I ever get 10000 orders in one day I'll have a problem - but that would be a good problem to have!)
This approach guarantees uniqueness and takes any processing load away from the insert transaction and into the batch routine, where it does not affect the user.
Use UUID function.
I don't know the source of your procedures in PHP that generates unique values. If it is library function they should guarantee that your value is really unique. Check in documentation. You should, hovewer, use this function all the time. If you, for example, use PHP function to generate unique value, and then you decide to use MySQL function, you can generate value that already exist. In this case putting UNIQUE INDEX on the column is also a good idea.
DELIMITER $$
USE `temp` $$
DROP PROCEDURE IF EXISTS `GenerateUniqueValue`$$
CREATE PROCEDURE `GenerateUniqueValue`(IN tableName VARCHAR(255),IN columnName VARCHAR(255))
BEGIN
DECLARE uniqueValue VARCHAR(8) DEFAULT "";
DECLARE newUniqueValue VARCHAR(8) DEFAULT "";
WHILE LENGTH(uniqueValue) = 0 DO
SELECT CONCAT(SUBSTRING('ABCDEFGHIJKLMNOPQRSTUVWXYZ123456789', RAND()*34+1, 1),
SUBSTRING('ABCDEFGHIJKLMNOPQRSTUVWXYZ123456789', RAND()*34+1, 1),
SUBSTRING('ABCDEFGHIJKLMNOPQRSTUVWXYZ123456789', RAND()*34+1, 1),
SUBSTRING('ABCDEFGHIJKLMNOPQRSTUVWXYZ123456789', RAND()*34+1, 1),
SUBSTRING('ABCDEFGHIJKLMNOPQRSTUVWXYZ123456789', RAND()*34+1, 1),
SUBSTRING('ABCDEFGHIJKLMNOPQRSTUVWXYZ123456789', RAND()*34+1, 1),
SUBSTRING('ABCDEFGHIJKLMNOPQRSTUVWXYZ123456789', RAND()*34+1, 1),
SUBSTRING('ABCDEFGHIJKLMNOPQRSTUVWXYZ123456789', RAND()*34+1, 1)
) INTO #newUniqueValue;
SET #rcount = -1;
SET #query=CONCAT('SELECT COUNT(*) INTO #rcount FROM ',tableName,' WHERE ',columnName,' like ''',newUniqueValue,'''');
PREPARE stmt FROM #query;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
IF #rcount = 0 THEN
SET uniqueValue = #newUniqueValue ;
END IF ;
END WHILE ;
SELECT uniqueValue;
END$$
DELIMITER ;
And call the stored procedure as GenerateUniqueValue('tableName','columnName'). This will give you a 8 digit unique character everytime.
To get unique and random looking tokens you could just encrypt your primary key i.e.:
SELECT HEX(AES_ENCRYPT(your_pk,'your_password')) AS 'token' FROM your_table;
This is good enough plus its reversable so you'd not have to store that token in your table but to generate it instead.
Another advantage is once you decode your PK from that token you do not have to do heavy full text searches over your table but simple and quick PK search.
Theres one small problem though. MySql supports different block encryption modes which if changed will completely change your token space making old tokens useless...
To overcome this one could set that variable before token generated i.e.:
SET block_encryption_mode = 'aes-256-cbc';
However that a bit waste... The solution for this is to attach an encryption mode used marker to the token:
SELECT CONCAT(CONV(CRC32(##GLOBAL.block_encryption_mode),10,35),'Z',HEX(AES_ENCRYPT(your_pk,'your_password'))) AS 'token' FROM your_table;
Another problem may come up if you wish to persist that token in your table on INSERT because to generate it you need to know primary_key for the record which was not inserted yet... Ofcourse you might just INSERT and then UPDATE with LAST_INSERT_ID() but again - theres a better solution:
INSERT INTO your_table ( token )
SELECT CONCAT(CONV(CRC32(##GLOBAL.block_encryption_mode),10,35),'Z',HEX(AES_ENCRYPT(your_pk,'your_password'))) AS 'token'
FROM information_schema.TABLES
WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = "your_table";
One last but not least advantage of this solution is you can easily replicate it in php, python, js or any other language you might use.
Below is just for reference of numeric unique random id...
it may help you...
$query=mysql_query("select * from collectors_repair");
$row=mysql_num_rows($query);
$ind=0;
if($row>0)
{
while($rowids=mysql_fetch_array($query))
{
$already_exists[$ind]=$rowids['collector_repair_reportid'];
}
}
else
{
$already_exists[0]="nothing";
}
$break='false';
while($break=='false'){
$rand=mt_rand(10000,999999);
if(array_search($rand,$alredy_exists)===false){
$break='stop';
}else{
}
}
echo "random number is : ".$echo;
and you can add char with the code like -> $rand=mt_rand(10000,999999) .$randomchar; // assume $radomchar contains char;
For uniqueness what I do is I take the Unix timestamp and append a random string to it and use that.
<?php
$hostname_conn = "localhost";
$database_conn = "user_id";
$username_conn = "root";
$password_conn = "";
$conn = mysql_pconnect($hostname_conn, $username_conn, $password_conn) or trigger_error(mysql_error(),E_USER_ERROR);
mysql_select_db($database_conn,$conn);
// run an endless loop
while(1) {
$randomNumber = rand(1, 999999);// generate unique random number
$query = "SELECT * FROM tbl_rand WHERE the_number='".mysql_real_escape_string ($randomNumber)."'"; // check if it exists in database
$res =mysql_query($query,$conn);
$rowCount = mysql_num_rows($res);
// if not found in the db (it is unique), then insert the unique number into data_base and break out of the loop
if($rowCount < 1) {
$con = mysql_connect ("localhost","root");
mysql_select_db("user_id", $con);
$sql = "insert into tbl_rand(the_number) values('".$randomNumber."')";
mysql_query ($sql,$con);
mysql_close ($con);
break;
}
}
echo "inserted unique number into Data_base. use it as ID";
?>
crypt() as suggested and store salt in some configuration file, Start salt from 1 and if you find duplicate move to next value 2. You can use 2 chars, but that will give you enough combination for salt.
You can generate string from openssl_random_pseudo_bytes(8). So this should give random and short string (11 char) when run with crypt().
Remove salt from result and there will be only 11 chars that should be enough random for 100+ millions if you change salt on every fail of random.
You might also consider using crypt()* to generate a [nearly-guaranteed] unique ID inside your contraints.
USE IT
$info = random_bytes(16);
$info[6] = chr(ord($info[6]) & 0x0f | 0x40);
$info[8] = chr(ord($info[8]) & 0x3f | 0x80);
$result =vsprintf('%s%s-%s-%s-%s-%s%s%s', str_split(bin2hex($info), 4));
return $result;
This generates random ids:
CREATE TABLE Persons (
ID Integer PRIMARY KEY AUTOINCREMENT,
LastName varchar(255) NOT NULL,
FirstName varchar(255),
Age int
);
You could use Twitter's snowflake.
In short, it generates a unique id based on time, server id and a sequence. It generates a 64-bit value so it is pretty small and it fits in an INT64. It also allows for sorting values correctly.
https://developer.twitter.com/en/docs/basics/twitter-ids
In sum, it allows multiple servers, highly concurrency, sorting value and all of them in 64 bits.
Here it is the implementation for MySQL
https://github.com/EFTEC/snowflake-mysql
It consists of a function and a table.