diff options
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 |