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Check if a table exists in Rails
...? 'kittens'
In Rails 2, 3 & 4 the API is about tables.
# Listing of all tables and views
ActiveRecord::Base.connection.tables
# Checks for existence of kittens table/view (Kitten model)
ActiveRecord::Base.connection.table_exists? 'kittens'
Getting the status of migrations:
# Tells you all...
Using sed and grep/egrep to search and replace
...ke:
.jpg | .png | .gif etc. This works well, now I would like to replace all strings found with .bmp
6 Answers
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Why should Java ThreadLocal variables be static
...
Because if it were an instance level field, then it would actually be "Per Thread - Per Instance", not just a guaranteed "Per Thread." That isn't normally the semantic you're looking for.
Usually it's holding something like objects that are scoped to a User Conversation, Web Request...
C char array initialization
...he question, it's worth pointing out that the C standard requires any partially-complete array initialisation to be padded with zero for the remaining elements (by the compiler). This goes for all data types, not just char.
– paddy
Sep 8 '13 at 21:54
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What is the point of Lookup?
... via that key in an efficient manner (rather than just iterating over them all, which is what GroupBy lets you do).
For example, you could take a load of .NET types and build a lookup by namespace... then get to all the types in a particular namespace very easily:
using System;
using System.Collec...
Enabling error display in PHP via htaccess only
... configuration files (e.g. httpd.conf) and .htaccess files. You will need "AllowOverride Options" or "AllowOverride All" privileges to do so. php.net/manual/en/configuration.changes.php
– silex
May 25 '11 at 17:01
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Difference between numeric, float and decimal in SQL Server
...Avoid using float or real columns in WHERE clause search conditions, especially the = and <> operators (Technet)
so generally because the precision provided by decimal is [10E38 ~ 38 digits] if your number can fit in it, and smaller storage space (and maybe speed) of Float is not important a...
Sublime Text 2: Trim trailing white space on demand
...ing spaces and delete them in a flash.
ST2 provides a way to automatically delete trailing spaces upon file
save. Depending on your settings, it may be more handy to just
highlight them and/or delete them by hand. This plugin provides just
that!
Usage: click "Edit / Trailing Spaces / De...
TFS: Updating branch with changes from main
...e Target branch drop-down, select your dev branch.
If you want a subset of all the changes in the mainline:
Choose the Selected changesets radio button, click Next.
Select the changesets that represent the merge from your other dev's branch into main, click Next.
Otherwise, keep All changes up to ...
Why do x86-64 instructions on 32-bit registers zero the upper part of the full 64-bit register?
...he CPU would have to wait on. The register renaming mechanism would essentially be defeated if it wasn't done that way.
This way you can write fast code using 32-bit values in 64-bit mode without having to explicitly break dependencies all the time. Without this behaviour, every single 32-bit instr...