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How do MySQL indexes work?
...index type is the B+Tree based index, that stores the elements in a sorted order. Also, you don't have to access the real table to get the indexed values, which makes your query return way faster.
The "problem" about this index type is that you have to query for the leftmost value to use the index....
Android: Clear Activity Stack
...ctivities one after the other through intents. Do I need to do anything in order to make sure the app doesn't crash with too many activities on the stack? Thanks!
– Ruchir Baronia
Dec 11 '15 at 14:14
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What is the purpose of setting a key in data.table?
...set a key (e.g. X[Y] ). As such, I wish to understand what a key does in order to properly set keys in my data tables.
2 ...
Throttling method calls to M requests in N seconds
...happen in big bursts by keeping the size M and delay N relatively small in order of handful millis. eg. M = 5, N = 20ms would provide a through put of 250/sec kepping burst to happen in size of 5.
– FUD
Sep 22 '12 at 10:51
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What is the use of the @ symbol in PHP?
... Cool feature.. It makes the use of isset()'s unnecessary in order to avoid undefined offset errors.
– W.M.
Dec 17 '16 at 20:55
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Group query results by month and year in postgresql
... Very nice! This is a superior answer, especially since you can order as well. Upvoted!
– bobmarksie
Jun 20 '16 at 10:35
2
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Bitwise operation and usage
...the data type, Python simply expands the width to cater for extra bits. In order to get the discarding behaviour in Python, you can follow a left shift with a bitwise and such as in an 8-bit value shifting left four bits:
bits8 = (bits8 << 4) & 255
With that in mind, another example of ...
Schema for a multilanguage database
...GRP_Name_i18n_cust, GRP_Name_i18n, GRP_Name) AS GroupName
FROM T_Groups
ORDER BY GroupName COLLATE {#COLLATION}
E) Then, you can do this in your DAL:
cmd.CommandText = cmd.CommandText.Replace("{#COLLATION}", auth.user.language.collation)
Which will then give you this perfectly composed SQL-Q...
How to create a multi-tenant database with shared table structures?
...able to estimate
prospective use with authority, but
think in terms of orders of magnitude:
are you building an application for
hundreds of tenants? Thousands? Tens
of thousands? More? The larger you
expect your tenant base to be, the
more likely you will want to consider
a more shar...
Converting an array of objects to ActiveRecord::Relation
...ECT .... WHERE `my_models`.id IN (2, 3, 4, 6, ....
Keep in mind that the ordering of the array will be lost - But since your objective is only to run a class method on the collection of these objects, I assume it won't be a problem.
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