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How to get first character of a string in SQL?
... @thomasrutter, Looking at an execution plan, SQL Server (at least 2008R2) internally translates LEFT(colName, length) into SUBSTRING(colName, 1, length). So there is no any optimizations here, it's just a preference.
– Alexander Abakumov
Sep 15 '14 at 15:15
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Is there a MySQL option/feature to track history of changes to records?
...dozen audit tables.
Instead, you can bake the concept of change over time into your schema design (this is the second option Keethanjan suggests). This is a change to your application, definitely at the business logic and persistence level, so it's not trivial.
For example, if you have a table li...
Which types can be used for Java annotation members?
Today I wanted to create my first annotation interface following this documentation and I got this compiler error
4 Answ...
How do I pass a unique_ptr argument to a constructor or a function?
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Here are the possible ways to take a unique pointer as an argument, as well as their associated meaning.
(A) By Value
Base(std::unique_ptr<Base> n)
: next(std::move(n)) {}
In order for the user to call this, they must do one of the following:
Base newBase(st...
How many concurrent requests does a single Flask process receive?
...a single core has multiple execution units and an instruction decoder that converts the "machine code" seen from the software side into the actual hardware micro-ops that are dispatched to the individual execution units.
– Michael Geary
Aug 10 '19 at 17:23
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Yii2 data provider default sorting
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$modelProduct = new Product();
$shop_id = (int)Yii::$app->user->identity->shop_id;
$queryProduct = $modelProduct->find()
->where(['product.shop_id' => $shop_id]);
$dataProviderProduct = new ActiveD...
Transactions in REST?
...playing with semantics to me; I'm uncomfortable with the nominalization of converting verbs into nouns to make it RESTful, "because it uses nouns (URIs) instead of verbs (RPC calls)". i.e. the noun "committed transaction resource" instead of the verb "commit this transaction". I guess one advantage...
How to printf uint64_t? Fails with: “spurious trailing ‘%’ in format”
I wrote a very simple test code of printf uint64_t:
3 Answers
3
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为AppInventor2开发拓展(Extension) · App Inventor 2 中文网
....ClipData;
import android.content.ClipboardManager;
import android.content.Intent;
import android.content.res.AssetFileDescriptor;
import android.net.Uri;
import com.google.appinventor.components.annotations.DesignerComponent;
import com.google.appinventor.components.annotations.DesignerProperty;
i...
Difference between __str__ and __repr__?
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__repr__: representation of python object usually eval will convert it back to that object
__str__: is whatever you think is that object in text form
e.g.
>>> s="""w'o"w"""
>>> repr(s)
'\'w\\\'o"w\''
>>> str(s)
'w\'o"w'
>>> eval(str(s))==s
Traceb...