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Diffstat (limited to 'railties/guides/source')
| -rw-r--r-- | railties/guides/source/active_support_core_extensions.textile | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/railties/guides/source/active_support_core_extensions.textile b/railties/guides/source/active_support_core_extensions.textile index 3370939861..368dcc00b6 100644 --- a/railties/guides/source/active_support_core_extensions.textile +++ b/railties/guides/source/active_support_core_extensions.textile @@ -1556,6 +1556,31 @@ end NOTE: Defined in +active_support/core_ext/string/inflections.rb+. +h5. +foreign_key+ + +The method +foreign_key+ gives a foreign key column name from a class name. To do so it demodulizes, underscores, and adds "_id": + +<ruby> +"User".foreign_key # => "user_id" +"InvoiceLine".foreign_key # => "invoice_line_id" +"Admin::Session".foreign_key # => "session_id" +</ruby> + +Pass a false argument if you do not want the underscore in "_id": + +<ruby> +"User".foreign_key(false) # => "userid" +</ruby> + +Associations use this method to infer foreign keys, for example +has_one+ and +has_many+ do this: + +<ruby> +# active_record/associations.rb +foreign_key = options[:foreign_key] || reflection.active_record.name.foreign_key +</ruby> + +NOTE: Defined in +active_support/core_ext/string/inflections.rb+. + h3. Extensions to +Numeric+ h4. Bytes |