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How to 'insert if not exists' in MySQL?
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Solution:
INSERT INTO `table` (`value1`, `value2`)
SELECT 'stuff for value1', 'stuff for value2' FROM DUAL
WHERE NOT EXISTS (SELECT * FROM `table`
WHERE `value1`='stuff for value1' AND `value2`='stuff for value2' LIMIT 1)
Explanation:
The innermost query
SELECT *...
Select parent element of known element in Selenium
I have a certain element that I can select with Selenium 1.
7 Answers
7
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How should I escape strings in JSON?
...read on.
Escape it according to the RFC. JSON is pretty liberal: The only characters you must escape are \, ", and control codes (anything less than U+0020).
This structure of escaping is specific to JSON. You'll need a JSON specific function. All of the escapes can be written as \uXXXX where XXXX...
Custom HTTP headers : naming conventions
...ed in section 2.2, 'Basic Rules'. Token is:
token = 1*<any CHAR except CTLs or separators>
In turn resting on CHAR, CTL and separators:
CHAR = <any US-ASCII character (octets 0 - 127)>
CTL = <any US-ASCII control character
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Default text which won't be shown in drop-down list
I have a select which initially shows Select language until the user selects a language. When the user opens the select, I don't want it to show a Select language option, because it's not an actual option.
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How can I find out what FOREIGN KEY constraint references a table in SQL Server?
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Here it is:
SELECT
OBJECT_NAME(f.parent_object_id) TableName,
COL_NAME(fc.parent_object_id,fc.parent_column_id) ColName
FROM
sys.foreign_keys AS f
INNER JOIN
sys.foreign_key_columns AS fc
ON f.OBJECT_ID = fc.constra...
Getting a list of files in a directory with a glob
...ing like that.
NSMutableArray* files = [NSMutableArray array];
glob_t gt;
char* pattern = "/bin/*";
if (glob(pattern, 0, NULL, &gt) == 0) {
int i;
for (i=0; i<gt.gl_matchc; i++) {
[files addObject: [NSString stringWithCString: gt.gl_pathv[i]]];
}
}
globfree(&gt);
retu...
Difference between SelectedItem, SelectedValue and SelectedValuePath
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Their names can be a bit confusing :). Here's a summary:
The SelectedItem property returns the entire object that your list is bound to. So say you've bound a list to a collection of Category objects (with each Category object having Name and ID properties). eg. ObservableCollection&l...
Azure table storage returns 400 Bad Request
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The specifed resource name contains invalid characters. my table name had dashes in it... just like my queue names...sigh. Hopefully searching picks this up for more people! see: stackoverflow.com/questions/45305556/…
– Nateous
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do { … } while (0) — what is it good for? [duplicate]
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@WChargin: the "goto fail" code in the article you linked too would have failed with a "break" too. Somebody just duplicated a line there. It wasn't goto's fault.
– Niccolo M.
Jun 15 '14 a...