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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...
Cross Domain Form POSTing
I've seen articles and posts all over (including SO) on this topic, and the prevailing commentary is that same-origin policy prevents a form POST across domains. The only place I've seen someone suggest that same-origin policy does not apply to form posts, is here .
...
Best branching strategy when doing continuous integration?
...
I find the topic really interesting since I heavily rely on branches on my daily job.
I remember Mark Shuttleworth proposing a model about keeping the main branch pristine while going beyond conventional CI. I posted about it here.
Since I'm ...
HTML 5: Is it , , or ?
I've tried checking other answers , but I'm still confused — especially after seeing W3schools HTML 5 reference .
27 An...
Mercurial — revert back to old version and continue from there
I'm using Mercurial locally for a project (it's the only repo there's no pushing/pulling to/from anywhere else).
7 Answers
...
How can I remove a trailing newline?
...; 'test string\n'.rstrip()
'test string'
Python's rstrip() method strips all kinds of trailing whitespace by default, not just one newline as Perl does with chomp.
>>> 'test string \n \r\n\n\r \n\n'.rstrip()
'test string'
To strip only newlines:
>>> 'test string \n \r\n\n\r \...
What's the purpose of the LEA instruction?
...ed to support high-level languages like Pascal and C, where arrays—especially arrays of ints or small structs—are common. Consider, for example, a struct representing (x, y) coordinates:
struct Point
{
int xcoord;
int ycoord;
};
Now imagine a statement like:
int y = points[i].ycoor...
Programmer Puzzle: Encoding a chess board state throughout a game
..., 2 bishops, 1 queen and 1 king as illustrated here:
Positions are generally recorded as a letter for the column followed by the number for the row so White’s queen is at d1. Moves are most often stored in algebraic notation, which is unambiguous and generally only specifies the minimal informa...
what's the difference between “hadoop fs” shell commands and “hdfs dfs” shell commands?
...s dfs instead.
hdfs dfs <args>
same as 2nd i.e would work for all the operations related to HDFS and is the recommended command instead of hadoop dfs
below is the list categorized as hdfs commands.
namenode|secondarynamenode|datanode|dfs|dfsadmin|fsck|balancer|fetchdt|oiv|dfsgroups
...
Why isn't SQL ANSI-92 standard better adopted over ANSI-89?
...n years after it was approved, it's about time people start using it! And all brands of SQL database now support it, so there's no reason to continue to use the nonstandard (+) Oracle syntax or *= Microsoft/Sybase syntax.
As for why it's so hard to break the developer community of the SQL-89 habit...