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How many database indexes is too many?
...
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...
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 (
...
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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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...
tinyxml XML解析库下载（tinyxml2.h 和 tinyxml2.cpp） - 源码下载 - 清泛...
...t accept to use COUNT in private part if COUNT is private
private:
union Chunk {
Chunk* next;
char mem[SIZE];
};
struct Block {
Chunk chunk[COUNT];
};
DynArray< Block*, 10 > _blockPtrs;
Chunk* _root;
int _currentAllocs;
int ...
Computed / calculated / virtual / derived columns in PostgreSQL
...y as column?
The expression (looking like a column) is not included in a SELECT * FROM tbl, though. You always have to list it explicitly.
Can also be supported with a matching expression index - provided the function is IMMUTABLE. Like:
CREATE FUNCTION col(tbl) ... AS ... -- your computed expr...
Xcode - How to fix 'NSUnknownKeyException', reason: … this class is not key value coding-compliant f
...ng from "File's Owner" under "Place Holders" to "view" under "Objects" and selecting the view outlet.
– Nirma
Aug 11 '11 at 14:49
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Add primary key to existing table
...PMID)
edit:
you can find the constraint name by using the query below:
select OBJECT_NAME(OBJECT_ID) AS NameofConstraint
FROM sys.objects
where OBJECT_NAME(parent_object_id)='Persion'
and type_desc LIKE '%CONSTRAINT'
sh...
What does Redis do when it runs out of memory?
...s reached Redis will try to remove keys
# according to the eviction policy selected (see maxmemory-policy).
#
# If Redis can't remove keys according to the policy, or if the policy is
# set to 'noeviction', Redis will start to reply with errors to commands
# that would use more memory, like SET, LPU...
Selecting the first “n” items with jQuery
With Jquery, I need to select just the first "n" items from the page, for example the first 20 links instead of selecting all of them with the usual
...