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add column to mysql table if it does not exist
...uld be to just try the ALTER TABLE ADD COLUMN command. It should throw an error if the column already exists.
ERROR 1060 (42S21): Duplicate column name 'newcolumnname'
Catch the error and disregard it in your upgrade script.
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Macro vs Function in C
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Macros are error-prone because they rely on textual substitution and do not perform type-checking. For example, this macro:
#define square(a) a * a
works fine when used with an integer:
square(5) --> 5 * 5 --> 25
but does ve...
Store output of subprocess.Popen call in a string
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if you want to get error stream add stderr: p = subprocess.Popen(["ntpq", "-p"], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
– Timofey
May 27 '14 at 12:29
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How can I send mail from an iPhone application
... didFinishWithResult:(MFMailComposeResult)result
error:(NSError*)error;
{
if (result == MFMailComposeResultSent) {
NSLog(@"It's away!");
}
[self dismissModalViewControllerAnimated:YES];
}
Remember to check if the device is configured for sending email:
if ([MFM...
Why can't Python find shared objects that are in directories in sys.path?
...ocal/lib $LD_LIBRARY_PATH /usr/local/lib But I still get the same error: $ python -c "import pycurl" Traceback (most recent call last): File "<string>", line 1, in <module> ImportError: libcurl.so.4: cannot open shared object file: No such file or directory
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Solutions for INSERT OR UPDATE on SQL Server
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Solutions provided by @Beau Crawford & @Esteban show general idea but error-prone.
To avoid deadlocks and PK violations you can use something like this:
begin tran
if exists (select * from table with (updlock,serializable) where key = @key)
begin
update table set ...
where key = @key
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How to quickly and conveniently disable all console.log statements in my code?
...se provide detail as to what doesn't work? Does the above line give you an error? If yes, what's the error message?
– SolutionYogi
Aug 1 '09 at 0:58
1
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How can I convert NSDictionary to NSData and vice versa?
...tingPrettyPrinted
error:&error];
NSDictionary *dictFromData = [NSJSONSerialization JSONObjectWithData:dataFromDict
options:NSJSONReadingAllowFragments
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How to manually create icns files using iconutil?
When I'm validating my app I get this error:
18 Answers
18
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Getting a list of files in a directory with a glob
...tManager];
NSArray *dirContents = [fm contentsOfDirectoryAtPath:bundleRoot error:nil];
NSPredicate *fltr = [NSPredicate predicateWithFormat:@"self ENDSWITH '.jpg'"];
NSArray *onlyJPGs = [dirContents filteredArrayUsingPredicate:fltr];
If you need to do it with NSURL instead it looks like this:
NSU...