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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....
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 ...
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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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
add a comment
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Error-Handling in Swift-Language
...or is not throwing at all.
2. Invoking function that may throw errors
In order to invoke function you need to use try keyword, like this
try summonDefaultDragon()
this line should normally be present do-catch block like this
do {
let dragon = try summonDefaultDragon()
} catch DragonError....
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
...
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...
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.
...
T-SQL split string
...elim, [Number]) - [Number])))
FROM (SELECT Number = ROW_NUMBER() OVER (ORDER BY name)
FROM sys.all_columns) AS x WHERE Number <= LEN(@List)
AND SUBSTRING(@Delim + @List, [Number], DATALENGTH(@Delim)/2) = @Delim
) AS y
);
GO
If you want to avoid the limitation of the length...