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How many database indexes is too many?
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It depends on the operations that occur on the table.
If there's lots of SELECTs and very few changes, index all you like.... these will (potentially) speed the SELECT statements up.
If the table is heavily hit by UPDATEs, INSERTs + DELETEs ... these will be very slow with lots of indexes since t...
Should you choose the MONEY or DECIMAL(x,y) datatypes in SQL Server?
...@num2 DECIMAL(19,4),
@num3 DECIMAL(19,4),
@num4 DECIMAL(19,4)
SELECT
@mon1 = 100, @mon2 = 339, @mon3 = 10000,
@num1 = 100, @num2 = 339, @num3 = 10000
SET @mon4 = @mon1/@mon2*@mon3
SET @num4 = @num1/@num2*@num3
SELECT @mon4 AS moneyresult,
@num4 AS numericresult...
UPDATE multiple tables in MySQL using LEFT JOIN
...= t1.id
SET t1.col1 = newvalue
WHERE t2.id IS NULL
Note that for a SELECT it would be more efficient to use NOT IN / NOT EXISTS syntax:
SELECT t1.*
FROM t1
WHERE t1.id NOT IN
(
SELECT id
FROM t2
)
See the article in my blog for performance details...
Does Spring Data JPA have any way to count entites using method name resolving?
...e UserRepository extends CrudRepository<User, Integer> {
@Query("SELECT COUNT(u) FROM User u WHERE u.name=?1")
Long aMethodNameOrSomething(String name);
}
or using @Param annotation also,
public interface UserRepository extends CrudRepository<User, Integer> {
@Query("SEL...
SELECT INTO using Oracle
I'm trying to do a SELECT INTO using Oracle. My query is:
3 Answers
3
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Notepad++ - How can I replace blank lines [duplicate]
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Press Ctrl+H (Replace)
Select Extended from SearchMode
Put \r\n\r\n in Find What
Put \r\n in ReplaceWith
Click on Replace All
share
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improve t...
Working copy locked error in tortoise svn while committing
...em. I did this lots of time... :)
Note. Make sure "Break locks" option is selected in the Cleanup dialog.
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Laravel Eloquent: Ordering results of all()
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Note, you can do:
$results = Project::select('name')->orderBy('name')->get();
This generate a query like:
"SELECT name FROM proyect ORDER BY 'name' ASC"
In some apps when the DB is not optimized and the query is more complex, and you need prevent gener...
Calendar Recurring/Repeating Events - Best Storage Method
... grabbing the events for the day it's at, the query would look like this:
SELECT EV.*
FROM `events` EV
RIGHT JOIN `events_meta` EM1 ON EM1.`event_id` = EV.`id`
RIGHT JOIN `events_meta` EM2 ON EM2.`meta_key` = CONCAT( 'repeat_interval_', EM1.`id` )
WHERE EM1.meta_key = 'repeat_start'
AND (
...
Android Spinner: Get the selected item change event
How can you set the event listener for a Spinner when the selected item changes?
16 Answers
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