I need to change the type of a column (wasserstand) from string to
integer, which already contains text.
My idea is to copy the string into a new scratch column, modify the
column type to integer and then manually set the appropriate ints.
After this, I want to remove the scratch string column in the next
migration.
The first migration should be done like this:
def self.up
tz = Teilzaehlung.all
ws = []
tz.each do |b|
ws << [b.id, b.wasserstand]
end
change_column(:teilzaehlungs, :wasserstand, :integer)
add_column(:teilzaehlungs, :wst, :string)
ws.each do |b|
beob = Teilzaehlung.find(b[0])
beob.update_attribute(:wasserstand, 0)
beob.update_attribute(:wst, b[1])
end
end
Interestingly, after running the migration, the new interger typed
column contains 0, but the scratch column wst is always NULL - even if
b[1] contains a string.
Why?
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Solution: Split the migration: The first creats the new column, the second processes the data. Looks like problem with migrations. -- Posted via http://www.ruby-forum.com/. -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
On Oct 31, 11:01 am, Fritz Trapper <li...-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org> wrote:> Solution: > Split the migration: The first creats the new column, the second > processes the data. > > Looks like problem with migrations. >Classes cache column information, but you can call MyClass.reset_column_information to clear that cache. Fred> -- > Posted viahttp://www.ruby-forum.com/.-- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.