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When and why are database joins expensive?
...s back to mitigating the size of the working set. Joins involving properly selected keys with correctly set up indexes are cheap, not expensive, because they allow significant pruning of the result before the rows are materialised.
Materialising the result involves bulk disk reads which are the mo...
What Java ORM do you prefer, and why? [closed]
...ay give jOOQ a try. You'll love it! :-)
Check out this example SQL:
// Select authors with books that are sold out
SELECT *
FROM T_AUTHOR a
WHERE EXISTS (SELECT 1
FROM T_BOOK
WHERE T_BOOK.STATUS = 'SOLD OUT'
AND T_BOOK.AUTHOR_ID ...
How can I update my ADT in Eclipse?
... to 23.0 or to 23.0.2 getting dependency issue when trying to Click (after selecting the developer tools and selecting the Same path https:// as above)
– user285oo6
Aug 18 '14 at 6:31
...
Drop columns whose name contains a specific string from pandas DataFrame
...
Use the DataFrame.select method:
In [38]: df = DataFrame({'Test1': randn(10), 'Test2': randn(10), 'awesome': randn(10)})
In [39]: df.select(lambda x: not re.search('Test\d+', x), axis=1)
Out[39]:
awesome
0 1.215
1 1.247
2 0.142
3...
Could not load file or assembly … An attempt was made to load a program with an incorrect format (Sy
... 32-Bit Applications.
Steps
Open IIS Manager
Click on Application Pools
Select whatever application pool you are using
From right pane, click Advanced Settings...
Set Enable 32-Bit Applications to True
share
...
Foreign Key to non-primary key
...int, with a scalar function checking the presence of the key:
IF EXISTS (SELECT * FROM sys.check_constraints WHERE object_id = OBJECT_ID(N'[dbo].[Check_RM_ApertureIDisValid_T_ZO_REM_AP_Raum_Reinigung]') AND parent_object_id = OBJECT_ID(N'[dbo].[T_ZO_REM_AP_Raum_Reinigung]'))
ALTER TABLE dbo.T_ZO_R...
CSS: background image on background color
I have panel which I colored blue if this panel is being selected (clicked on it). Additionally, I add a small sign ( .png image) to that panel, which indicates that the selected panel has been already selected before.
...
How do I stop Chrome from yellowing my site's input boxes?
...e property to none.
input[type="text"], input[type="password"], textarea, select {
outline: none;
}
In cases where the browser may add a background color as well this can be fixed by something like
:focus { background-color: #fff; }
...
Pandas every nth row
...] # Excludes every 3rd row starting from 0
df2 = df[df.index % 3 == 0] # Selects every 3rd raw starting from 0
This arithmetic based sampling has the ability to enable even more complex row-selections.
This assumes, of course, that you have an index column of ordered, consecutive, integers star...
The term 'Get-ADUser' is not recognized as the name of a cmdlet
...es & Features. Within Add Roles and Features Wizard, on Features tab, select Remote Server Administration Tools, select - Role Admininistration Tools - Select AD DS and DF LDS Tools.
After that, you can see the PS Active Directory package.
...