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A beginner's guide to SQL database design [closed]
...ure that every column that you do "where column = val" in any query has an index. Maybe not the most perfect index in the world for the data type, but at least an index.
Set up your foreign keys. Also set up ON DELETE and ON MODIFY rules where relevant, to either cascade or set null, depending on yo...
How do I profile memory usage in Python?
...h.heap()
Partition of a set of 48477 objects. Total size = 3265516 bytes.
Index Count % Size % Cumulative % Kind (class / dict of class)
0 25773 53 1612820 49 1612820 49 str
1 11699 24 483960 15 2096780 64 tuple
2 174 0 241584 7 2338364 72 dict of...
How to install Java SDK on CentOS?
...ested:
wget -q http://www.oracle.com/technetwork/java/javase/downloads/index.html -O ./index.html && grep -Eoi ']+>' index.html | grep -Eoi '/technetwork/java/javase/downloads/jdk8-downloads-[0-9]+.html' | (head -n 1) | awk '{print "http://www.oracle.com"$1}' | xargs wget --no-cookies...
Initial size for the ArrayList
... and is always greater or equal to the size of the list.
When calling set(index, element) on the list, the index relates to the actual number of the list elements (=size) (which is zero in your code, therefore the AIOOBE is thrown), not to the array length (=capacity) (which is an implementation de...
efficient way to implement paging
... (Order By CodCity) As Row,
CodCity //here is only accessed by the Index as CodCity is the primary
From dbo.mtcity
)
Select [t0].[CodCity],
[t0].[CodCountry],
[t0].[CodRegion],
[t0].[Name],
[t0].[Code]
From CityEntities c
Inner Join dbo.MtCity t0 on c.C...
Get item in the list in Scala?
How in the world do you get just an element at index i from the List in scala?
4 Answers
...
How to apply a CSS filter to a background image
...and left: 0; right: 0;. The difference in displaying them comes from the z-index values which have been set differently for the elements.
.background-image {
position: fixed;
left: 0;
right: 0;
z-index: 1;
display: block;
background-image: url('https://i.imgur.com/lL6tQfy.png'...
Logical operators for boolean indexing in Pandas
I'm working with boolean index in Pandas.
The question is why the statement:
3 Answers
...
What is the most efficient way to create a dictionary of two pandas Dataframe columns?
...
In [9]: pd.Series(df.Letter.values,index=df.Position).to_dict()
Out[9]: {1: 'a', 2: 'b', 3: 'c', 4: 'd', 5: 'e'}
Speed comparion (using Wouter's method)
In [6]: df = pd.DataFrame(randint(0,10,10000).reshape(5000,2),columns=list('AB'))
In [7]: %timeit dict(...
Fastest check if row exists in PostgreSQL
...1 I have strong performance drop because Postgres uses Seq Scan instead of Index Scan. And analyze doesn't help.
– FiftiN
Jul 7 '16 at 10:41
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