Read tables from SQL code

ruby-talk
1

hi,
i have a SQL code like this one:

SELECT Select_List
   FROM Table_List
   [WITH (BUFFERING = lExpr)]
   [WHERE Conditions]
   [GROUP BY Column_List]
   [UNION Clause]
   [HAVING Conditions]
   [ORDER BY Column_List]
   [INTO Clause | TO Clause ]
   [Additional_Display_Options]

can i read/save with ruby the columns involved in that SQL select?

···

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2

can i read/save with ruby the columns involved in that SQL select?

If you use Sequel you can retrieve the columns for arbitrary SQL like
this:

  require 'sequel/mysql' # assuming you're using MySQL
  DB = Sequel('mysql://localhost/mydb')
  DB['select * from items'].columns #=> [:id, :name, ...]

But if you're already using Sequel why not construct your queries
using Ruby instead of SQL, e.g.:

  dataset = DB.query do
    where {:name =~ /^abc/ && :price < 100}
    order_by :name
  end
  p dataset.columns
  dataset.each {|r| p r}

You can find more information about Sequel here:

  Google Code Archive - Long-term storage for Google Code Project Hosting.

And you can also get help on Sequel-talk:

  http://groups.google.com/group/sequel-talk

best
Sharon

···

from :items

3

Ruby DBI will let you do exact SQL, like DBI in other languages.

ActiveRecord can do some of that select statement, but some of it no.
ActiveRecord does have the ability to execute direct SQL statements though.