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| author | Prem Sichanugrist <s@sikachu.com> | 2011-10-20 17:15:28 -0400 |
|---|---|---|
| committer | Prem Sichanugrist <s@sikachu.com> | 2011-10-20 17:15:28 -0400 |
| commit | f0be2cb19274bb6029f84ca274a72c4d7fbee2d3 (patch) | |
| tree | 6f8914cebe9dc61dc94eed1a0dec8cbba23c2398 /activerecord/lib | |
| parent | d64e0955d04a40355e312ca4ee57b2c9a8e248cc (diff) | |
| download | rails-f0be2cb19274bb6029f84ca274a72c4d7fbee2d3.tar.gz rails-f0be2cb19274bb6029f84ca274a72c4d7fbee2d3.tar.bz2 rails-f0be2cb19274bb6029f84ca274a72c4d7fbee2d3.zip | |
Add some note on adding index to HABTM table
Diffstat (limited to 'activerecord/lib')
| -rw-r--r-- | activerecord/lib/active_record/associations.rb | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb index 2449df079a..34684ad2f5 100644 --- a/activerecord/lib/active_record/associations.rb +++ b/activerecord/lib/active_record/associations.rb @@ -1432,6 +1432,10 @@ module ActiveRecord # end # end # + # It's also a good idea to add indexes to each of those columns to speed up the joins process. + # However, in MySQL it is advised to add a compound index for both of the columns as MySQL only + # uses one index per table during the lookup. + # # Adds the following methods for retrieval and query: # # [collection(force_reload = false)] |