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Two single-column indexes vs one two-column index in MySQL?
... the statement I provided.
Additionally, MySQL can only use one index per SELECT so a covering index would be the best means of optimizing your queries.
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How to automatically indent source code?
...
Ctrl+E, D - Format whole doc
Ctrl+K, Ctrl+F - Format selection
Also available in the menu via Edit|Advanced.
Thomas
Edit-
Ctrl+K, Ctrl+D - Format whole doc in VS 2010
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What is the difference between Views and Materialized Views in Oracle?
... you. The downside of a view is that its performance depends on how good a select statement the view is based on. If the select statement used by the view joins many tables, or uses joins based on non-indexed columns, the view could perform poorly.
Materialized views
They are similar to regular vi...
MYSQL OR vs IN performance
...for future Googlers. Total count of returned results is 7264 out of 10000
SELECT * FROM item WHERE id = 1 OR id = 2 ... id = 10000
This query took 0.1239 seconds
SELECT * FROM item WHERE id IN (1,2,3,...10000)
This query took 0.0433 seconds
IN is 3 times faster than OR
...
Explain ExtJS 4 event handling
...js4.1)
Lets say we have a controller Station (Sencha MVC examples) with a select box:
Ext.define('Pandora.controller.Station', {
extend: 'Ext.app.Controller',
...
init: function() {
this.control({
'stationslist': {
selectionchange: this.onStationSel...
How do I temporarily disable triggers in PostgreSQL?
...ct = 'disable';
else
act = 'enable';
end if;
for r in select c.relname from pg_namespace n
join pg_class c on c.relnamespace = n.oid and c.relhastriggers = true
where n.nspname = nsp
loop
execute format('alter table %I %s trigger all', r.relname, act)...
Is having an 'OR' in an INNER JOIN condition a bad idea?
... a MERGE JOIN.
It can be expressed as a concatenation of two resultsets:
SELECT *
FROM maintable m
JOIN othertable o
ON o.parentId = m.id
UNION
SELECT *
FROM maintable m
JOIN othertable o
ON o.id = m.parentId
, each of them being an equijoin, however, SQL Server's optimiz...
live output from subprocess command
...ptimization: If we are only using one pipe, or no pipe at
# all, using select() or threads is unnecessary.
if [self.stdin, self.stdout, self.stderr].count(None) >= 2:
But, alas, here we've made at least two, and maybe three, different pipes, so the count(None) returns either 1 or 0. We...
How do you search an amazon s3 bucket?
...to access many nodes at once ala more traditional datastores that offer a (SELECT * FROM ... WHERE ...) (in a SQL model).
What you will need to do is perform ListBucket to get a listing of objects in the bucket and then iterate over every item performing a custom operation that you implement - whic...
CSS '>' selector; what is it? [duplicate]
...
> selects immediate children
For example, if you have nested divs like such:
<div class='outer'>
<div class="middle">
<div class="inner">...</div>
</div>
<div class="middle...