大约有 44,000 项符合查询结果（耗时：0.0543秒） [XML]
Can I add a UNIQUE constraint to a PostgreSQL table, after it's already created?
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If you want to let PostgreSQL generate the index name, use ALTER TABLE tablename ADD UNIQUE (columns);. (Note that the CONSTRAINT keyword must be omitted.)
– jpmc26
Nov 26 '14 at 1:41
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Using Python's os.path, how do I go up one directory?
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Using abspath will just clean it up a bit. If it's not there, the actual string for the path name will be /Users/hobbes3/Sites/mysite/mysite/../templates, which is perfectly fine, but just a little more cluttered. It also ensures that Django's reminder to use absolute...
Using CMake with GNU Make: How can I see the exact commands?
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The top google hit recommends "if you want to see solely the g++ command lines, you should use grep & Co. - if possible - in connection with verbose Makefiles". Perhaps developers with lots of cmake experience have other advice.
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Are database triggers evil? [closed]
... @HGLEM, agree there should be a specialist to work out triggers. Real life scenario - there isn't. Real life scenario - days spent trying to identify a bug related to a forgotten trigger. Real life scenario - trigger logic is being desperately pushed out into application logic where it can be ea...
Concatenate a vector of strings/character
If I have a vector of type character, how can I concatenate the values into string? Here's how I would do it with paste() :
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Java: function for arrays like PHP's join()?
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If you were looking for what to use in android, it is:
String android.text.TextUtils.join(CharSequence delimiter, Object[] tokens)
for example:
String joined = TextUtils.join(";", MyStringArray);
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mongo group query how to keep fields
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If you want to keep the information about the first matching entries for each group, you can try aggregating like:
db.test.aggregate({
$group: {
_id : '$name',
name : { $first: '$name' },
age : { $first: '$age' },...
URL Fragment and 302 redirects
...rences, including relative references and fragments, along
with some clarifications as to when use of fragments would not be
appropriate. (Section 7.1.2)
The important points from Section 7.1.2. Location:
If the Location value provided in a 3xx (Redirection) response does
not have a fra...
Getting error: Peer authentication failed for user “postgres”, when trying to get pgsql working with
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local all postgres md5
* If you can't find this file, running locate pg_hba.conf should show you where the file is.
After altering this file, don't forget to restart your PostgreSQL server. If you're on Linux, that would be sudo service postgresql r...
Implode an array with JavaScript?
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Array.join is what you need, but if you like, the friendly people at phpjs.org have created implode for you.
Then some slightly off topic ranting. As @jon_darkstar alreadt pointed out, jQuery is JavaScript and not vice versa. You don't need to know JavaScri...