As we all know, we will use the mysql_query api to send a query to the server, and the query are passed by a string as the parameter. And we will have to formulate the string outside the mysql_query called by some C functions like sprintf.For example,
sprintf(buffer, “insert into table(describe) values(‘%s’)”, strA);
mysql_query(..., buffer);
The ‘describe’ is a VARCHAR(150).
In some special cases, one of our functions will cat several C style string into a long one remaining all the ending ‘\0’ to form a binary, ie in C form catting “abc” and “efg” into “abc\0efg\0”, of course with the length given out to the caller(in this case, it is 8). However, the out binary can NEVER be used in the sprintf above as strA, as the C functions will truncate the string by meeting the first ‘\0’.
Is there anything special we can do to fulfill our needs? We want to insert a binary into a column defined as VARCHAR. We have tried to change all the ‘\0’ into ‘\0’ literally, which seems to work good but time and codes consuming. Is there any alternative easier method?
Thanks in advance.
you should use mysql_real_escape_string() to escape this string.
Related
Unlike PHP, I don't believe mySQL has any preg_replace() feature, only matching via REGEXP. Here are the strings I have in the code:
http://ourcompany.com/theapplestore/...
http://ourcompany.com/anotherstore/...
http://ourcompany.com/yetanotherstore/...
As you can see, there is a constant in there, http://ourcompany.com/, but there is also a variable string namely theapplestore, anotherstore, etc. etc.
I want to replace the constant string, plus the variable string(s), and then the trailing slash (/) after the variable string(s), with a single shortcode value, namely {{store url=''}}
EDIT
If it helps, the store codes are always the same length, they are going to be
sch131785
sch185399
sch634019
etc.
i.e., they are all 9 characters long
How would I do this? Thanks.
I thought this might be useful: there is currently NO WAY to do this in mysql. Find using REGEXP, yes; replace, no. That said, there is another post with an extension library mentioned, sagi:
Is there a MySQL equivalent of PHP's preg_replace?
MariaDB-10.0.5 has REGEXP_REPLACE(), REGEXP_INSTR() and REGEXP_SUBSTR()
You can use following regex,
(ourcompany.com\/\w+\/)
Demo
Uses the concept of Group Capture
I am trying to convert larg number to string in MUMPS but I can't.
Let me explain what I would like to do :
s A="TEST_STRING#12168013110012340000000001"
s B=$P(A,"#",2)
s TAB(B)=1
s TAB(B)=1
I would like create an array TAB where variable B will be a primary key for array TAB.
When I do ZWR I will get
A="TEST_STRING#12168013110012340000000001"
B="12168013110012340000000001"
TAB(12168013110012340000000000)=1
TAB("12168013110012340000000001")=1
as you can see first SET recognize variable B as a number (wrongly converted) and second SET recognize variable B as a string ( as I would like to see ).
My question is how to write SET command to recognize variable B as a string instead of number ( which is wrong in my opinion ).
Any advice/explanation will be helpful.
This may be a limitation of sorting/storage mechanism built into MUMPS and is different between different MUMPS implementations. The cause is that while variable values in MUMPS are non typed, index values are -- and numeric indices are sorted before string ones. When converting a large string to number, rounding errors may occur. To prevent this from happening, you need to add a space before number in your index to explicitly treat it as string:
s TAB(" "_B)=1
As far as I know, Intersystems Cache doesn't have this limitation -- at least your code works fine in Cache and in documentation they claim to support up to 309 digits:
http://docs.intersystems.com/cache20141/csp/docbook/DocBook.UI.Page.cls?KEY=GGBL_structure#GGBL_C12648
I've tried to recreate your scenario, but I am not seeing the issue you're experiencing.
It actually is not possible ( in my opinion ) for the same command executed immediately ( one execution after another) to produce two different results.
s TAB(B)=1
s TAB(B)=1
for as long the value of B did not change between the executions, the result should be:
TAB("12168013110012340000000001")=1
Example of what GT.M implementation of MUMPS returns in your case
I'm looking around to encode/cast/convert a string into numbers within a query. Like ASCII() but it only returns the left-most character to its relative code. Is there any function or method available on this topic? -which is actually decode-able
JUST For example:
METHOD("test-string") # Outputs: 25478596325417
This will work for strings up to 8 characters long.
To encode:
SELECT CONV(HEX(string), 16, 10);
To decode:
SELECT UNHEX(CONV(number, 10, 16));
MySQL supports integers up to 64 bit long, and this method uses 8 bits per character. Therefore using this method you can store up to 64 / 8 = 8 characters in an integer.
If hexadecimal is good enough for your application, then then function hex() does what you want. For instance, you can try:
select hex('abc'), hex('abcd')
This will work on arbitrary strings. If this doesn't quite work, then perhaps there is a way to convert the hex representation to something appropriate.
By the way, unhex() will return the original string.
You could use
COMPRESS('ABC)
To get a binary string that is not the string. It can compress an arbitrary size. But it is not clear what you are going to do with the number -- or how you need to store it.
Try this one.
SELECT CAST(HEX(your_string) AS DECIMAL);
I admit, I didn't test it, but it should work.
EDIT:
Some other databases (e.g. Oracle, DB2, PostgreSQL) have the function TRANSLATE() for it. Unfortunately MySQL does not support it. And as far as I know no replacement for this function in MySQL exists currently. So using nested REPLACE() is probably the only option currently.
I am writing an SQL statement class that will allow a user to create a properly formatted SQL statement string. This class will have a method -(id)initWithFormat:(NSString *)format, ... that needs to work just like the NSString variadic method. The one thing I want to change, however, is any NSString's passed as an argument must be automatically escaped by the initWithFormat.
For example, after initialising a statement like this (notice the string argument has a "'" that needs to be escaped):
MyStatement *statement = [[MyStatement alloc] initWithFormat:#"UPDATE myTable SET myField = %# WHERE myID = %lu", #"David's Room", 1234];
The resulting statement string should be:
#"UPDATE myTable SET myField = "David\'s Room WHERE myID = 1234"
Writing the function to escape a string is easy but I can't work out how to include this in the initWithFormat method. Can anyone tell me how to accomplish this? I have thought about emulating the NSString initWithFormat functionality by stepping through each character of the format string, finding any chars starting with % and somehow using a switch statement to append the correct type to a NSMutableString but this seems overly complicated (i.e. some format specifiers are more than 1 char e.g. Signed 16-bit integer %hi and the function should take into account positional specifiers such as %1$# etc).
All the variadic tutorials I have seen concentrate on nil-terminated lists and don't show how to emulate initWithFormat effectively (including the technical Q&A from Apple that is deceptively titled "How can I write a method that takes a variable number of arguments, like NSString's +stringWithFormat:?").
Thanks in advance.
So lets just say I have a table with just an ID is an int. I have discovered that running:
SELECT *
FROM table
WHERE ID = '32anystring';
Returns the row where id = 32. Clearly 32 != '32anystring'.
This seems very strange. Why does it do this? Can it be turned off? What is the best workaround?
It is common behavior in most programming languages to interpret leading numerals as a number when converting a string to a number.
There are a couple of ways to handle this:
Use prepared statements, and define the placeholder where you are putting the value to be of a numeric type. This will prevent strings from being put in there at all.
Check at a higher layer of the application to validate input and make sure it is numeric.
Use the BINARY keyword in mysql (I'm just guessing that this would work, have never actually tried it as I've always just implemented a proper validation system before running a query) -
SELECT *
FROM table
WHERE BINARY ID = '32anystring';
You need to read this
http://dev.mysql.com/doc/refman/5.1/en/type-conversion.html
When you work on, or compare two different types, one of them will be converted to the other.
MySQL conversion of string->number (you can do '1.23def' * 2 => 2.46) parses as much as possible of the string as long as it is still a valid number. Where the first letter cannot be part of a number, the result becomes 0