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Getting “Lock wait timeout exceeded; try restarting transaction” even though I'm not using a transac
... holding a record lock on some record (you're updating every record in the table!) for too long, and your thread is being timed out.
You can see more details of the event by issuing a
SHOW ENGINE INNODB STATUS
after the event (in sql editor). Ideally do this on a quiet test-machine.
...
How big can a MySQL database get before performance starts to degrade
...data. The most important scalability factor is RAM. If the indexes of your tables fit into memory and your queries are highly optimized, you can serve a reasonable amount of requests with a average machine.
The number of records do matter, depending of how your tables look like. It's a difference ...
INSERT IF NOT EXISTS ELSE UPDATE?
...ot in the insert list will be set to NULL if the row already exists in the table. This is why there's a subselect for the ID column: In the replacement case the statement would set it to NULL and then a fresh ID would be allocated.
This approach can also be used if you want to leave particular fiel...
Laravel Eloquent Sum of relation's column
... is no price column. It looks like eloquent is not looking at that Product table at all....
– theAdmiral
Feb 10 '14 at 15:22
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Rails Model find where not equal
...User.where.not(user_id: me)
In Rails 3.x
GroupUser.where(GroupUser.arel_table[:user_id].not_eq(me))
To shorten the length, you could store GroupUser.arel_table in a variable or if using inside the model GroupUser itself e.g., in a scope, you can use arel_table[:user_id] instead of GroupUser.are...
What is the difference between DAO and Repository patterns?
...lection of objects.
DAO would be considered closer to the database, often table-centric.
Repository would be considered closer to the Domain, dealing only in Aggregate Roots.
Repository could be implemented using DAO's, but you wouldn't do the opposite.
Also, a Repository is generally a narro...
mailto link with HTML body
... tab is ctrl-i which is %09. Take a look at an ASCII chart like this [asciitable.com/index/asciifull.gif]. The control characters are from 1 through 31. @wide_eyed_pupil
– Jim Bergman
Dec 7 '12 at 6:16
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LEFT JOIN only first row
...n…but exactly what I want. In my case, I just want the first ID from the table I'm joining in.
– Drew Stephens
Feb 8 '17 at 20:42
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How do I create an Excel (.XLS and .XLSX) file in C# without installing Microsoft Office?
...asy to use. Plus it has a DataSetHelper that lets you use DataSets and DataTables to easily work with Excel data.
ExcelLibrary seems to still only work for the older Excel format (.xls files), but may be adding support in the future for newer 2007/2010 formats.
You can also use EPPlus, which work...
MySQL skip first 10 results
...
There is an OFFSET as well that should do the trick:
SELECT column FROM table
LIMIT 10 OFFSET 10
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