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Best practices for in-app database migration for Sqlite
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I maintain an application that periodically needs to update a sqlite database and migrate old databases to the new schema and here's what I do:
For tracking the database version, I use the built in user-version variable that sqlite provides (sqlite does nothing w...
Flatten List in LINQ
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Try SelectMany()
var result = iList.SelectMany( i => i );
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jQuery find parent form
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I would suggest using closest, which selects the closest matching parent element:
$('input[name="submitButton"]').closest("form");
Instead of filtering by the name, I would do this:
$('input[type=submit]').closest("form");
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Web-scraping JavaScript page with Python
...a web driver fast enough and easy to get the work done.
Once you have installed Phantom JS, make sure the phantomjs binary is available in the current path:
phantomjs --version
# result:
2.1.1
Example
To give an example, I created a sample page with following HTML code. (link):
<!DOCTYPE ht...
Why is iterating through a large Django QuerySet consuming massive amounts of memory?
...rst time you iterate over it. For example, this will print the headline of all entries in the database:
for e in Entry.objects.all():
print e.headline
So your ten million rows are retrieved, all at once, when you first enter that loop and get the iterating form of the queryset. The wait ...
MySQL: how to get the difference between two timestamps in seconds
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You could use the TIMEDIFF() and the TIME_TO_SEC() functions as follows:
SELECT TIME_TO_SEC(TIMEDIFF('2010-08-20 12:01:00', '2010-08-20 12:00:00')) diff;
+------+
| diff |
+------+
| 60 |
+------+
1 row in set (0.00 sec)
You could also use the UNIX_TIMESTAMP() function as @Amber suggested in a...
iOS 7 - How to display a date picker in place in a table view?
...hose values.
As a delegate to this table, the sample uses the method "didSelectRowAtIndexPath" to open the UIDatePicker control.
For iOS 6.x and earlier, UIViewAnimation is used for sliding the UIDatePicker up on-screen and down off-screen. For iOS 7.x, the UIDatePicker is added in-line to th...
Python: split a list based on a condition?
What's the best way, both aesthetically and from a performance perspective, to split a list of items into multiple lists based on a conditional? The equivalent of:
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Why is Lisp used for AI? [closed]
...utes of macro work this week, I implemented an ad-hoc buggy version of SQL Select. It goes like this: (query SELECT * FROM dataset WHERE expr).
– Paul Nathan
Nov 12 '11 at 20:08
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How to write “Html.BeginForm” in Razor
...data" }))
{
@Html.ValidationSummary(true)
<fieldset>
Select a file <input type="file" name="file" />
<input type="submit" value="Upload" />
</fieldset>
}
and generates as expected:
<form action="/Upload/Upload" enctype="multipart/form-data" m...