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author | Gonçalo Silva <goncalossilva@gmail.com> | 2011-03-28 04:20:49 +0100 |
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committer | Gonçalo Silva <goncalossilva@gmail.com> | 2011-03-28 04:20:49 +0100 |
commit | 6f0caa1a534a065753d51430b649114bc8bf54ac (patch) | |
tree | af9657373436a38ef7828b26a804d1fe12e479ad /railties/guides/source/active_record_querying.textile | |
parent | 726b7ede54031eecfcee34eec80040553e9ad19f (diff) | |
parent | 245542ea2994961731be105db6c076256a22a7a9 (diff) | |
download | rails-6f0caa1a534a065753d51430b649114bc8bf54ac.tar.gz rails-6f0caa1a534a065753d51430b649114bc8bf54ac.tar.bz2 rails-6f0caa1a534a065753d51430b649114bc8bf54ac.zip |
Merge branch 'master' of https://github.com/rails/rails into performance_test
Diffstat (limited to 'railties/guides/source/active_record_querying.textile')
-rw-r--r-- | railties/guides/source/active_record_querying.textile | 36 |
1 files changed, 35 insertions, 1 deletions
diff --git a/railties/guides/source/active_record_querying.textile b/railties/guides/source/active_record_querying.textile index 009d541106..2c5d9e67e3 100644 --- a/railties/guides/source/active_record_querying.textile +++ b/railties/guides/source/active_record_querying.textile @@ -76,7 +76,7 @@ Primary operation of <tt>Model.find(options)</tt> can be summarized as: h4. Retrieving a Single Object -Active Record lets you retrieve a single object using three different ways. +Active Record lets you retrieve a single object using five different ways. h5. Using a Primary Key @@ -130,6 +130,40 @@ SELECT * FROM clients ORDER BY clients.id DESC LIMIT 1 <tt>Model.last</tt> returns +nil+ if no matching record is found. No exception will be raised. +h5. +first!+ + +<tt>Model.first!</tt> finds the first record. For example: + +<ruby> +client = Client.first! +=> #<Client id: 1, first_name: "Lifo"> +</ruby> + +SQL equivalent of the above is: + +<sql> +SELECT * FROM clients LIMIT 1 +</sql> + +<tt>Model.first!</tt> raises +RecordNotFound+ if no matching record is found. + +h5. +last!+ + +<tt>Model.last!</tt> finds the last record. For example: + +<ruby> +client = Client.last! +=> #<Client id: 221, first_name: "Russel"> +</ruby> + +SQL equivalent of the above is: + +<sql> +SELECT * FROM clients ORDER BY clients.id DESC LIMIT 1 +</sql> + +<tt>Model.last!</tt> raises +RecordNotFound+ if no matching record is found. + h4. Retrieving Multiple Objects h5. Using Multiple Primary Keys |