From a migration. I want to initialize a new column called "ident"
with
a string equal to "prec-#{id}" - where id is meant to be the id column
of the relevant row. This works:
Precinct.update_all("ident = ''prec-'' || id ")
I am confused about whether that bit of SQL is being parsed by Rails
code, or whether it''s given to Sqlite, in which case I am writing a
database-dependent bit of code.
Thanks for your assistance!
Pito
--
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.
> From a migration. I want to initialize a new column called "ident" > with > a string equal to "prec-#{id}" - where id is meant to be the id column > of the relevant row. This works: > > Precinct.update_all("ident = ''prec-'' || id ") > > I am confused about whether that bit of SQL is being parsed by Rails > code, or whether it''s given to Sqlite, in which case I am writing a > database-dependent bit of code.I believe it''s going to the database, but I haven''t verified it. Follow the source though to make sure... first line of update_all is: sql = "UPDATE #{quoted_table_name} SET #{sanitize_sql_for_assignment(updates)} " So, worth looking at sanatize_sql_for_assignment to see what it might be doing. -philip -- 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.
Philip Hallstrom wrote:>> From a migration. I want to initialize a new column called "ident" >> with >> a string equal to "prec-#{id}" - where id is meant to be the id column >> of the relevant row. This works: >> >> Precinct.update_all("ident = ''prec-'' || id ") >> >> I am confused about whether that bit of SQL is being parsed by Rails >> code, or whether it''s given to Sqlite, in which case I am writing a >> database-dependent bit of code. > > I believe it''s going to the database, but I haven''t verified it.It would have to be going to the DB, or else || wouldn''t have its SQL sense of concatenation. To the OP: if this column is just going to be the id with a constant prefix, then you don''t need it in the DB!> > Follow the source though to make sure... > > first line of update_all is: > sql = "UPDATE #{quoted_table_name} SET > #{sanitize_sql_for_assignment(updates)} " > So, worth looking at sanatize_sql_for_assignment to see what it might > be doing. > > -philipBest, -- Marnen Laibow-Koser http://www.marnen.org marnen-sbuyVjPbboAdnm+yROfE0A@public.gmane.org -- 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@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
Marnen Laibow-Koser wrote:> To the OP: if this column is just going to be the id with a constant > prefix, then you don''t need it in the DB!It''s initializing existing records in a migration. Over time the match will not be present. To the other point about "||" meaning concatenation. Thats what got me thinking as some other SQLs use "+" and others use CONCAT(). -- 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 Feb 10, 2010, at 4:31 PM, Pito Salas wrote:> Marnen Laibow-Koser wrote: > >> To the OP: if this column is just going to be the id with a constant >> prefix, then you don''t need it in the DB! > > It''s initializing existing records in a migration. Over time the match > will not be present. > > To the other point about "||" meaning concatenation. Thats what got me > thinking as some other SQLs use "+" and others use CONCAT().|| is standard. That said, MySQL doesn''t follow the standard and treats || as OR. Unless you start it up in ''ansi'' mode. Might not matter a bit for you, but if it does, you could always do the concatenation in rails via find/save/update_attribute. Slower, but would work. Here''s something else that just got me as I don''t use Sqlite much... named_scope :approved, :conditions => "is_approved = true" Will fail on sqlite as it doesn''t recognize true. named_scope :approved, :conditions => ["is_approved = ?", true] works though. I do the [] thing for everything else but figured ''true'' was safe. Guess not. -philip -- 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.