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Why does PostgreSQL perform sequential scan on indexed column?
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If the SELECT returns more than approximately 5-10% of all rows in the table, a sequential scan is much faster than an index scan.
This is because an index scan requires several IO operations for each row (look up the row ...
How do I convert datetime to ISO 8601 in PHP
...Time::ATOM); // Updated ISO8601
Procedural
For older versions of PHP, or if you are more comfortable with procedural code.
echo date(DATE_ISO8601, strtotime('2010-12-30 23:21:46'));
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Convert NSURL to local file path
..., unescaped with the stringByReplacingPercentEscapesUsingEncoding: method. If the receiver does not conform to RFC 1808, returns nil.
If this URL object contains a file URL (as determined with isFileURL), the return value of this method is suitable for input into methods of NSFileManager or NSP...
how to add records to has_many :through association in rails
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@Mischa how should i handle error if House.find(params[:house_id]) is nill.. i got error of TypeMismatch if params[:house_id] is nil.. i already using rescue. but is there any better_way..??
– Vishal
Jul 30 '16 at 10:5...
Most efficient way to convert an HTMLCollection to an Array
...st.
A performance comparison for the mentioned methods: http://jsben.ch/h2IFA
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How to declare a variable in MySQL?
... access any user-defined variable without declaring it or
initializing it. If you refer to a variable that has not been
initialized, it has a value of NULL and a type of string.
SELECT @var_any_var_name
You can initialize a variable using SET or SELECT statement:
SET @start = 1, @finish = 10; ...
What Product Flavor does Android Studio build by default in build.gradle?
...d Studio as a development tool. When there are several product flavors specified in build.gradle , we notice that Android Studio builds the first one specified alphabetically. Is there a way to tell Android Studio to build and test only a specific product flavor during development?
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How to create materialized views in SQL Server?
...er of constraints and limitations - those are outlined in the white paper. If you do this - that's all there is. The view is being updated automatically, no maintenance needed.
Additional resources:
Creating and Optimizing Views in SQL Server
SQL Server Indexed Views
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JSON.parse vs. eval()
...t using eval() to parse incoming JSON is a bad idea. I'm just wondering if JSON.parse() - which I assume is a part of JavaScript and not a browser-specific function - is more secure.
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Copying files using rsync from remote server to local machine
...d copy inside /path/to/local/storage. Like so /path/to/local/storage/copy. If that's what you want great. However a more common scenario is you want to copy the contents of the remote directory into a directory in your local. Then you would do /path/to/copy/ which would place the contents inside the...