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What's the $unwind operator in MongoDB?
..., consider this array tags : [ "fun" , "good" , "fun" ] as another related table (can't be a lookup/reference table because values has some duplication) named "tags". Remember SELECT generally produces things vertical, so unwind the "tags" is to split() vertically into table "tags".
The end result ...
How does C compute sin() and other math functions?
...ximations for both sin(x) and cos(x), then using values from a precomputed table to refine the approximation.
When |x| > 2, none of the above algorithms would work, so the code starts by computing some value closer to 0 that can be fed to sin or cos instead.
There's yet another branch to deal wit...
MySQL offset infinite rows
I would like to construct a query that displays all the results in a table, but is offset by 5 from the start of the table. As far as I can tell, MySQL's LIMIT requires a limit as well as an offset. Is there any way to do this?
...
What are file descriptors, explained in simple terms?
...file in operating system.
If your process opens 10 files then your Process table will have 10 entries for file descriptors.
Similarly when you open a network socket, it is also represented by an integer and it is called Socket Descriptor.
I hope you understand.
...
How to check if object (variable) is defined in R?
...paces of attached packages, this would also fall short:
> exists("data.table")
[1] FALSE
require(data.table)
> exists("data.table", inherits = FALSE)
[1] FALSE
> exists("data.table")
[1] TRUE
The only thing I can think of to get around this -- to search in attached packages but not in ba...
MySQL Error 1215: Cannot add foreign key constraint
... the keys I'm trying to use as a foreign key are primary keys in their own tables. I have done both of these things, if I'm not mistaken. Any other help you guys could offer?
...
Iterate over model instance field names and values in template
.... Think of it as just a standard output of the values of that instance in table format, with the field name (verbose_name specifically if specified on the field) in the first column and the value of that field in the second column.
...
Count number of records returned by group by
... count(*) RecordsPerGroup,
COUNT(*) OVER () AS TotalRecords
from temptable
group by column_1, column_2, column_3, column_4
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How to “fadeOut” & “remove” a div in jQuery?
... <title>JS Bin</title>
</head>
<body>
<table class="table table-striped table-bordered table-hover">
<thead>
<tr>
<th>id</th>
<th>firstname</th>
<th>lastname</th>
&l...
How to select a single field for all documents in a MongoDB collection?
...
get all data from table
db.student.find({})
SELECT * FROM student
get all data from table without _id
db.student.find({}, {_id:0})
SELECT name, roll FROM student
get all data from one field with _id
db.student.find({}, {ro...