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Does C# have extension properties?
Does C# have extension properties?
6 Answers
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How to upgrade PostgreSQL from version 9.6 to version 10.1 without losing data?
... using the PostgreSQL database for my Ruby on Rails application (on Mac OS X 10.9).
15 Answers
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mongoDB/mongoose: unique if not null
...thout the field by setting the sparse option to true when defining the index. As in:
email : {type: String, trim: true, index: true, unique: true, sparse: true}
Or in the shell:
db.users.ensureIndex({email: 1}, {unique: true, sparse: true});
Note that a unique, sparse index still does not all...
Why is rbindlist “better” than rbind?
... known for being slow when using rbind.data.frame
Where does it really excel
Some questions that show where rbindlist shines are
Fast vectorized merge of list of data.frames by row
Trouble converting long list of data.frames (~1 million) to single data.frame using do.call and ldply
These have...
Execute and get the output of a shell command in node.js
In a node.js, I'd like to find a way to obtain the output of a Unix terminal command. Is there any way to do this?
5 Answer...
Sending POST data in Android
I'm experienced with PHP, JavaScript and a lot of other scripting languages, but I don't have a lot of experience with Java or Android.
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Is there a REAL performance difference between INT and VARCHAR primary keys?
...nt to be speedy, because they work with large volumes of data or they are executed very frequently. If these queries benefit from eliminating a join, and do not suffer by using a varchar primary key, then do it.
Don't use either strategy for all tables in your database. It's likely that in some c...
Performant Entity Serialization: BSON vs MessagePack (vs JSON)
... As the result, MessagePack can serialize objects smaller than BSON.
For example, a simple map {"a":1, "b":2} is serialized in 7 bytes with MessagePack, while BSON uses 19 bytes.
BSON supports in-place updating
With BSON, you can modify part of stored object without re-serializing the whole of the...
Guaranteed lifetime of temporary in C++?
...is created within a function call but not used as a parameter? Here's an example class:
5 Answers
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How to implement the activity stream in a social network
I'm developing my own social network, and I haven't found on the web examples of implementation the stream of users' actions... For example, how to filter actions for each users? How to store the action events? Which data model and object model can I use for the actions stream and for the actions it...