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How to set default values in Rails?
... If you know you'll always want that default value for that column on that table, setting them in a DB migration file is the easiest way:
class SetDefault < ActiveRecord::Migration
def self.up
change_column :people, :last_name, :type, :default => "Doe"
end
def self.down
# You c...
MySQL order by before group by
...hor is to use a subquery to return the max date and then join that to your table on both the post_author and the max date.
The solution should be:
SELECT p1.*
FROM wp_posts p1
INNER JOIN
(
SELECT max(post_date) MaxPostDate, post_author
FROM wp_posts
WHERE post_status='publish'
...
What is the default height of UITableViewCell?
...
tableView.rowHeight
– Hunter
Sep 21 '11 at 3:14
|
show 8 more com...
What is an ORM, how does it work, and how should I use one? [closed]
...(book);
}
With an ORM library, it would look like this:
book_list = BookTable.query(author="Linus");
The mechanical part is taken care of automatically via the ORM library.
Pros and Cons
Using ORM saves a lot of time because:
DRY: You write your data model in only one place, and it's easier...
Best GWT widget library? [closed]
...Building MVP apps
After, you can use any widget of these libraries (say a table, or a combobox, a datepicker, etc) and incorporate it to your project. Try to use extended components ONLY if you don't see a way to do it with vanilla GWT. This way you don't tie yourself to these libraries which are A...
AWS MySQL RDS vs AWS DynamoDB [closed]
I've been using MySQL for a fair while now and I'm comfortable with its structure & SQL Queries etc.
4 Answers
...
How to install mongoDB on windows?
...st imagine an SQL server or Oracle Db with entirely different rows in same table? Is it possible in our relational DB table? This is how mongo works. I will show you how we can do that…
First I will show you how the data will look in a relational DB.
For example consider an Employee table and a S...
Test for non-zero length string in Bash: [ -n “$var” ] or [ “$var” ]
...on that shows more differences between [ (aka test) and [[.
The following table shows that whether a variable is quoted or not, whether you use single or double brackets and whether the variable contains only a space are the things that affect whether using a test with or without -n/-z is suitable ...
how to show alternate image if source image is not found? (onerror working in IE but not in mozilla)
I need to show an alternate image in cell of table if source image is not found.
Currently below code is used to do so.
3 A...
Allowed characters in filename [closed]
...
You should start with the Wikipedia Filename page. It has a decent-sized table (Comparison of filename limitations), listing the reserved characters for quite a lot of file systems.
It also has a plethora of other information about each file system, including reserved file names such as CON under...