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Are foreign keys really necessary in a database design?
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If you need an index create one, this should not be a primary reason for FKs. (In fact in certain circumstances (More inserts than selects for example) maintaining a FK might be slower. )
– Robert
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PHPExcel auto size column width
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If a column is set to AutoSize, PHPExcel attempts to calculate the column width based on the calculated value of the column (so on the result of any formulae), and any additional characters added by format masks such as thous...
Rails 4 - Strong Parameters - Nested Objects
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As odd as it sound when you want to permit nested attributes you do specify the attributes of nested object within an array. In your case it would be
Update as suggested by @RafaelOliveira
params.require(:measurement)
.permit(:name, :groundtruth => [:type, :coordinates => []])
On ...
Tar archiving that takes input from a list of files
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What if the .txt files list is really huge ? Should one use xarg command with tar -r.. instead of tar -c.. ?
– Stphane
Dec 15 '15 at 22:42
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How to make my layout able to scroll down?
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As David Hedlund said, ScrollView can contain just one item... so if you had something like this:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_pa...
Python try…except comma vs 'as' in except
What is the difference between ',' and 'as' in except statements, eg:
5 Answers
5
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MySQL DISTINCT on a GROUP_CONCAT()
...ct to each other ("test1 test2 test3" is distinct than "test1 test3", even if some tests contained in the whole string are duplicated).
What we need to do here is to split each string into different rows, and we first need to create a numbers table:
CREATE TABLE numbers (n INT);
INSERT INTO number...
Find rows with multiple duplicate fields with Active Record, Rails & Postgres
...l).having("count(*) > 1")
Also, this is a little unrelated but handy. If you want to see how times each combination was found, put .size at the end:
User.select(:first,:email).group(:first,:email).having("count(*) > 1").size
and you'll get a result set back that looks like this:
{[nil, n...
How do I POST JSON data with cURL?
...is short for --header, -d for --data)
Note that -request POST is optional if you use -d, as the -d flag implies a POST request.
On Windows, things are slightly different. See the comment thread.
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How do I use FileSystemObject in VBA?
...stbox
Click on the OK button.
This can also be done directly in the code if access to the VBA object model has been enabled.
Access can be enabled by ticking the check-box Trust access to the VBA project object model found at File > Options > Trust Center > Trust Center Settings > Mac...