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Foreign keys in mongo?
...his:
class Student
include Mongoid::Document
field :name
embeds_many :addresses
embeds_many :scores
end
class Address
include Mongoid::Document
field :address
field :city
field :state
field :postalCode
embedded_in :student
end
class Score
include Mongoi...
In Python, what is the difference between “.append()” and “+= []”?
...
In general case append will add one item to the list, while += will copy all elements of right-hand-side list into the left-hand-side list.
Update: perf analysis
Comparing bytecodes we can assume that append version wastes cycles in LOAD_ATTR + CALL_FUNCTION, and += version -- in BUILD_LIST. App...
Pass Variables by Reference in Javascript
... it means that it's possible to pass a simple variable in such a way as to allow a function to modify that value in the calling context. So:
function swap(a, b) {
var tmp = a;
a = b;
b = tmp; //assign tmp to b
}
var x = 1, y = 2;
swap(x, y);
alert("x is " + x + ", y is " + y); // "...
What is the difference between the Data Mapper, Table Data Gateway (Gateway), Data Access Object (DA
...thods like insert, update, delete and in table data gateway you will find getcustomerbyId, getcustomerbyName, etc.
Data transfer object differs from the above two patterns, mainly because it is a distribution pattern and not a data source pattern as above two patterns. Use it mainly when you are wo...
How do I find numeric columns in Pandas?
Let's say df is a pandas DataFrame.
I would like to find all columns of numeric type.
Something like:
11 Answers
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MySQL OPTIMIZE all tables?
...ZE TABLE command which can be used to reclaim unused space in a MySQL install. Is there a way (built-in command or common stored procedure) to run this optimization for every table in the database and/or server install, or is this something you'd have to script up yourself?
...
Saving utf-8 texts in json.dumps as UTF8, not as \u escape sequence
...ure_ascii=False switch to json.dumps(), then encode the value to UTF-8 manually:
>>> json_string = json.dumps("ברי צקלה", ensure_ascii=False).encode('utf8')
>>> json_string
b'"\xd7\x91\xd7\xa8\xd7\x99 \xd7\xa6\xd7\xa7\xd7\x9c\xd7\x94"'
>>> print(json_string.decode(...
Oracle “Partition By” Keyword
...ts in that State.
It is like getting the results of a GROUP BY (SUM, AVG, etc.) without the aggregating the result set (i.e. removing matching records).
It is useful when you use the LAST OVER or MIN OVER functions to get, for example, the lowest and highest salary in the department and then use t...
Rails: Open link in new tab (with 'link_to')
...
The target: :_blank parameter should be a parameter of link_to, whereas you put it in image_tag parameters. Modify your code like this:
<%= link_to image_tag("facebook.png", class: :facebook_icon, alt: "Facebook"), "http://www.facebo...
CSS Properties: Display vs. Visibility
...(i.e. it has height and width properties that you can set, it's floatable, etc), or an inline-block (i.e. it acts like a block box but is laid inline instead) and some others (list-item, table, table-row, table-cell, flex, etc).
When you set an element to display: block but also set visibility: hid...