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how to emulate “insert ignore” and “on duplicate key update” (sql merge) with postgresql?
...start transaction; create temporary table temporary_table as select * from test where false; copy temporary_table from 'data_file.csv'; lock table test; update test set data=temporary_table.data from temporary_table where test.id=temporary_table.id; insert into test select * from temporary_table whe...
The most accurate way to check JS object's type?
...
That test on jsPerf isn't quite accurate. Those tests are not equal (testing for the same thing). E.g., typeof [] returns "object", typeof {} also returns "object", even though one is an object Array and the other is an object Ob...
Adding an identity to an existing column
...ess than 5 seconds.
Here's a code sample of how it works.
CREATE TABLE Test
(
id int identity(1,1),
somecolumn varchar(10)
);
INSERT INTO Test VALUES ('Hello');
INSERT INTO Test VALUES ('World');
-- copy the table. use same schema, but no identity
CREATE TABLE Test2
(
id int NO...
is_null($x) vs $x === null in PHP [duplicate]
...there is a time difference between using === and is_null(). Did some quick testing and got these results:
<?php
//checking with ===
$a = array();
$time = microtime(true);
for($i=0;$i<10000;$i++) {
if($a[$i] === null) {
//do nothing
}
}
echo 'Testing with === ', microtime(tru...
“#include” a text file in a C program as a char[]
...o the new raw string literals:
In C++ do this:
const char *s =
#include "test.txt"
;
In the text file do this:
R"(Line 1
Line 2
Line 3
Line 4
Line 5
Line 6)"
So there must only be a prefix at the top of the file and a suffix at the end of it. Between it you can do what you want, no special es...
How to configure Ruby on Rails with no database?
... yes, this works with Rails 4 :) - just validated. If you want to ditch test unit use: rails new myApp-O --skip-bundle -T
– Chris Hough
Oct 8 '13 at 7:01
1
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Load dimension value from res/values/dimension.xml from source code
...
In my dimens.xml I have
<dimen name="test">48dp</dimen>
In code If I do
int valueInPixels = (int) getResources().getDimension(R.dimen.test)
this will return 72 which as docs state is multiplied by density of current phone (48dp x 1.5 in my case)
...
CASCADE DELETE just once
...ascade delete without thinking through all of the repercussions.
I'm still testing out this function, so there may be bugs in it -- but please don't try it if your DB has multi column primary (and thus foreign) keys. Also, the keys all have to be able to be represented in string form, but it could b...
Why do we need entity objects? [closed]
... separating your domain model from your database model.
What I do is use Test Driven Development so I write my UI and Model layers first and the Data layer is mocked, so the UI and model is build around domain specific objects, then later I map these objects to what ever technology I'm using the t...
Using curl to upload POST data with files
... -F "filecomment=This is an image file" \
-F "image=@/home/user1/Desktop/test.jpg" \
localhost/uploader.php
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