3 questions

Rails
1

validates_format_of :name, :with => /\A(\w(?:[/’ -.])?)*\Z/i

What does the ‘i’ do at the end of the regular expression?

Should I do validation for attributes that are not from a form?

def self.up
create_table :customers do |t|
t.column :number, :integer, :limit => 4
end
end

As far as I know, Mysql 5.0.27 uses Int for number here. Will also a
small number need 4 bytes in the database?

2

validates_format_of :name, :with => /\A(\w(?:[/’ -.])?)*\Z/i

What does the ‘i’ do at the end of the regular expression?

/i makes a regex case-insensitive. See
http://www.ruby-doc.org/core/classes/Regexp.html#M001219
for other Regexp options

3

Hi Martin,

Martin Luy wrote:

validates_format_of :name, :with => /\A(\w(?:[/’ -.])?)*\Z/i

What does the ‘i’ do at the end of the regular expression?

It makes the match case insensitive

Should I do validation for attributes that are not from a form?

Yes. If you expect a field to conform to condition that is not inherent
in it’s column type you should validate the data. It will catch bugs
and keep you data more coherent.

def self.up
create_table :customers do |t|
t.column :number, :integer, :limit => 4
end
end

As far as I know, Mysql 5.0.27 uses Int for number here. Will also a
small number need 4 bytes in the database?

Yes. It really isn’t a big deal. There are ways around this, but
before you go hacking into the code ask yourself if this isn’t premature
optimization. unless you are storing ~10^6 rows your space savings will
not be appreciable.

J. F. Miller

4

Martin Luy wrote:

validates_format_of :name, :with => /\A(\w(?:[/’ -.])?)*\Z/i

What does the ‘i’ do at the end of the regular expression?

Case-insensitive

Should I do validation for attributes that are not from a form?

Depends on how much you trust yourself. Where is the data coming from?

def self.up
create_table :customers do |t|
t.column :number, :integer, :limit => 4
end
end

As far as I know, Mysql 5.0.27 uses Int for number here. Will also a
small number need 4 bytes in the database?

As far as I can tell, it doesn’t matter what “limit” you give to an int
in MySQL , it always uses 4 bytes. I don’t believe you have access to
the various int types (bigint, smallint, mediumint) through migrations.

-matthew