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Select distinct values from a table field
...ant any ordering to be applied to a query, not even the default ordering, call order_by() with no parameters.
and distinct() in the note where it discusses issues with using distinct() with ordering.
To query your DB, you just have to call:
models.Shop.objects.order_by().values('city').distinct(...
Refresh a page using PHP
How can I refresh a page using PHP periodically? If I can not do it by PHP, what is the best recommended scenario?
13 Answe...
Sequelize.js delete query?
Is there a way to write a delete/deleteAll query like findAll?
9 Answers
9
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Checking if an instance's class implements an interface?
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As therefromhere points out, you can use class_implements(). Just as with Reflection, this allows you to specify the class name as a string and doesn't require an instance of the class:
interface IInterface
{
}
class TheClass implements IInterface
{
}
$interfaces = cl...
Converting a Java Keystore into PEM Format
...- keystore in java format.
foo.p12 - keystore in PKCS#12 format.
foo.pem - all keys and certs from keystore, in PEM format.
(This last file can be split up into keys and certificates if you like.)
Command summary - to create JKS keystore:
keytool -keystore foo.jks -genkeypair -alias foo \
...
How do I update/upsert a document in Mongoose?
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Mongoose now supports this natively with findOneAndUpdate (calls MongoDB findAndModify).
The upsert = true option creates the object if it doesn't exist. defaults to false.
var query = {'username': req.user.username};
req.newData.username = req.user.username;
MyModel.findOneAndUpd...
Capture characters from standard input without waiting for enter to be pressed
...oo much on the terminal used that may be connected with stdin (they are usually line buffered). You can, however use a library for that:
conio available with Windows compilers. Use the _getch() function to give you a character without waiting for the Enter key. I'm not a frequent Windows developer...
Delete a key from a MongoDB document using Mongoose
...de-mongodb-native driver. Each model has a collection object that contains all the methods that node-mongodb-native offers. So you can do the action in question by this:
User.collection.update({_id: user._id}, {$unset: {field: 1 }});
Since version 2.0 you can do:
User.update({_id: user._id}, {$u...
How do I check in JavaScript if a value exists at a certain array index?
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Conceptually, arrays in JavaScript contain array.length elements, starting with array[0] up until array[array.length - 1]. An array element with index i is defined to be part of the array if i is between 0 and array.length - 1 inclu...
Matplotlib (pyplot) savefig outputs blank image
...values that depend whether or not T0 exists.
Second, after plt.show() is called, a new figure is created. To deal with this, you can
Call plt.savefig('tessstttyyy.png', dpi=100) before you call plt.show()
Save the figure before you show() by calling plt.gcf() for "get current figure", then you ca...