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SQL Server IN vs. EXISTS Performance
...e).
Both forms can be converted to join forms internally, have the join order reversed, and run as loop, hash or merge--based on the estimated row counts (left and right) and index existence in left, right, or both sides.
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E11000 duplicate key error index in mongodb mongoose
... null value.
In other words, a sparse index is ok with multiple documents all having null values.
sparse indexes
From comments:
Your error says that the key is named mydb.users.$email_1 which makes me suspect that you have an index on both users.email and users.local.email (The former being old an...
test if event handler is bound to an element in jQuery [duplicate]
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Because it was used (.data) by jQuery to stock their internal events logic.
– adriendenat
Jul 12 '13 at 15:55
1
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Why should you use an ORM? [closed]
...sily formed in declarative constraints. E.g. "customer gets 10% off entire order the first time they buy more than three pairs of slacks from the same brand." How would you put that business rule into the database (keep in mind an answer involving stored procedures is clunky).
–...
Android: Specify two different images for togglebutton using XML
... @I82Much a switch would always select the "right one" regardless of order, this behaves more like a lengthy if-elseif-elseif-else with conditions like state_x == true && state_y == false && state_z = true.
– TWiStErRob
Dec 18 '14 at 10:46...
How do you unit test private methods?
...etimes like to call private methods from test methods. Most of the time in order to prevent code duplication for test data generation...
Microsoft provides two mechanisms for this:
Accessors
Goto the class definition's source code
Right-click on the name of the class
Choose "Create Private Acces...
PostgreSQL create table if not exists
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CREATE TABLE myschema.mytable (i integer);
END IF;
END
$func$;
Call:
SELECT create_mytable(); -- call as many times as you want.
Notes:
The columns schemaname and tablename in pg_tables are case-sensitive. If you double-quote identifiers in the CREATE TABLE statement, you need ...
Java's Interface and Haskell's type class: differences and similarities?
...> so that the compareTo(T otherobject) kind of has type t -> t -> Ordering. But that still requires the programmer to follow this rule, and also causes headaches when people want to make a function that uses this interface, they have to have recursive generic type parameters.
Also, you won...
In Docker, what's the difference between a container and an image? [duplicate]
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An image is an ordered collection of root filesystem changes and the corresponding execution parameters for use within a container runtime. Images are read-only.
https://docs.docker.com/glossary/?term=image
A container is an active (or ...
IIS7 deployment - duplicate 'system.web.extensions/scripting/scriptResourceHandler' section
...un your ASP.Net 3.5 app using the version 4 app pool (depending on install order this is the default app pool), you will get this error.
When I moved to using the version 2.0 app pool. The error went away. I then had to deal with the error when serving WCF .svc :
HTTP Error 404.17 - Not Found The...