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How to speed up insertion performance in PostgreSQL
...rypto module) is (a lot) faster than uuid_generate_v4()
=# explain analyze select uuid_generate_v4(),* from generate_series(1,10000);
QUERY PLAN
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How to specify font attributes for all elements on an html web page?
...es use: *,:before,:after{font-family:inherit;} if you must use a universal selector, use inheritance instead.
– darcher
Jun 5 '15 at 16:15
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How to map a composite key with JPA and Hibernate?
... way you write queries (making them more or less verbose):
with IdClass
select t.levelStation from Time t
with EmbeddedId
select t.timePK.levelStation from Time t
References
JPA 1.0 specification
Section 2.1.4 "Primary Keys and Entity Identity"
Section 9.1.14 "EmbeddedId Annotation"
Sect...
How can I tell if my server is serving GZipped content?
...erested). You can tell using Developer Tools (F12). Go to the Network tab, select the file you want to examine and then look at the Headers tab on the right. If you are gzipped, then you will see that in the Content-Encoding.
In this example, slider.jpg is indeed being gzipped.
Compare that to t...
How do I force Postgres to use a particular index?
...d, client_id, date, and description. You want to run the following query:
SELECT client_id, SUM(amount)
FROM transactions
WHERE date >= 'yesterday'::timestamp AND date < 'today'::timestamp AND
description = 'Refund'
GROUP BY client_id
PostgreSQL may choose to use the index transaction...
How to store arrays in MySQL?
... retrieve a person and all of their fruit you can do something like this:
SELECT p.*, f.*
FROM person p
INNER JOIN person_fruit pf
ON pf.person_id = p.id
INNER JOIN fruits f
ON f.fruit_name = pf.fruit_name
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I have an error: setOnItemClickListener cannot be used with a spinner, what is wrong?
...nner.
setOnItemClickListener cannot be used with a Spinner. Use setOnItemSelectedListener instead.
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SQLite table constraint - unique on multiple columns
...Some other title');
sqlite> .mode col
sqlite> .headers on
sqlite> select * from t1;
id a b
---------- ---------- ----------------
1 Alice Some other title
2 Bob Palindromic guy
3 Charles chucky cheese
sq...
Carriage Return/Line Feed in .Net Resource File (App_GlobalResources)
...n Visual Studio:
Right click to the resource file
Click to Open with ...
Select XML (Text) Editor with Encoding
Click OK
Click OK again for encoding selection (auto-detect)
Search for the name (key) of your text (e.g. "MY_TEXT")
Edit the text inside of the <value> tag. For linebreaks just pu...
What is the difference between SqlCommand.CommandTimeout and SqlConnection.ConnectionTimeout?
...ndTimeout = timeout limit for your SQL query. Means, how much time a (eg: SELECT, UPDATE) query can take for its execution. If it exceeds SqlCommand.CommandTimeout, then it stops execution. A command timeout error will occur.
SqlConnection.ConnectionTimeout = timeout limit for your connection. Mea...