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Diffstat (limited to 'railties/guides/source/active_record_querying.textile')
| -rw-r--r-- | railties/guides/source/active_record_querying.textile | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/railties/guides/source/active_record_querying.textile b/railties/guides/source/active_record_querying.textile index 2c5d9e67e3..f3a10b8b92 100644 --- a/railties/guides/source/active_record_querying.textile +++ b/railties/guides/source/active_record_querying.textile @@ -962,6 +962,26 @@ Client.exists? The above returns +false+ if the +clients+ table is empty and +true+ otherwise. +You can also use +any?+ and +many?+ to check for existence on a model or relation. + +<ruby> +# via a model +Post.any? +Post.many? + +# via a named scope +Post.recent.any? +Post.recent.many? + +# via a relation +Post.where(:published => true).any? +Post.where(:published => true).many? + +# via an association +Post.first.categories.any? +Post.first.categories.many? +</ruby> + h3. Calculations This section uses count as an example method in this preamble, but the options described apply to all sub-sections. |