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MySQL indexes - what are the best practices?
...going on.
Broadly speaking, an index imposes an ordering on the rows of a table.
For simplicity's sake, imagine a table is just a big CSV file. Whenever a row is inserted, it's inserted at the end. So the "natural" ordering of the table is just the order in which rows were inserted.
Imagine y...
Normalizing mousewheel speed across browsers
...k put together a great solution to this problem.
I have tested on a data table that I'm building using React and it scrolls like butter!
This solution works on a variety of browsers, on Windows/Mac, and both using trackpad/mouse.
// Reasonable defaults
var PIXEL_STEP = 10;
var LINE_HEIGHT = 4...
Django: How to completely uninstall a Django app?
...dy management command that will give you the necessary SQL to drop all the tables for an app. See the sqlclear docs for more information. Basically, running ./manage.py sqlclear my_app_name gets you get the SQL statements that should be executed to get rid of all traces of the app in your DB. You st...
What are database normal forms and can you give examples? [closed]
...y normalization, which is a process of organizing columns (attributes) and tables (relations) to reduce data redundancy and improve data integrity. (as written on Wikipedia ).
...
How Do I Choose Between a Hash Table and a Trie (Prefix Tree)?
So if I have to choose between a hash table or a prefix tree what are the discriminating factors that would lead me to choose one over the other. From my own naive point of view it seems as though using a trie has some extra overhead since it isn't stored as an array but that in terms of run time (a...
Insert multiple rows WITHOUT repeating the “INSERT INTO …” part of the statement?
...
INSERT INTO dbo.MyTable (ID, Name)
SELECT 123, 'Timmy'
UNION ALL
SELECT 124, 'Jonny'
UNION ALL
SELECT 125, 'Sally'
For SQL Server 2008, can do it in one VALUES clause exactly as per the statement in your question (you just need to add a comm...
Best way to get identity of inserted row?
...
@@IDENTITY returns the last identity value generated for any table in the current session, across all scopes. You need to be careful here, since it's across scopes. You could get a value from a trigger, instead of your current statement.
SCOPE_IDENTITY() returns the last identity val...
How do I make a column unique and index it in a Ruby on Rails migration?
... What is the best way to do it? Also is there a way to index a column in a table?
8 Answers
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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
2
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SQL Server - where is “sys.functions”?
...ECT *
FROM sys.objects
WHERE type IN ('FN', 'IF', 'TF') -- scalar, inline table-valued, table-valued
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