diff options
| author | xue <> | 2007-09-28 18:08:20 +0000 | 
|---|---|---|
| committer | xue <> | 2007-09-28 18:08:20 +0000 | 
| commit | 199fc1254f84f851a2894df94487a45ed68f7c98 (patch) | |
| tree | 55f899a4ed1a885ea2334db959acbe91e5e573a3 /demos/quickstart/protected/pages/Database | |
| parent | 4b292ae910c08c68ee62e5a96d7b879573921eee (diff) | |
Fixed #665.
Diffstat (limited to 'demos/quickstart/protected/pages/Database')
| -rw-r--r-- | demos/quickstart/protected/pages/Database/ActiveRecord.page | 57 | 
1 files changed, 48 insertions, 9 deletions
| diff --git a/demos/quickstart/protected/pages/Database/ActiveRecord.page b/demos/quickstart/protected/pages/Database/ActiveRecord.page index 481985e9..a28c3d5e 100644 --- a/demos/quickstart/protected/pages/Database/ActiveRecord.page +++ b/demos/quickstart/protected/pages/Database/ActiveRecord.page @@ -52,21 +52,21 @@      </ul>  <h2>Design Implications</h2>  <p> -Prado's implementation of Active Record does not maintain referential identity. Each object obtained using  -Active Record is a copy of the data in the database. For example, If you ask for  -a particular customer and get back a <tt>Customer</tt> object, the next time you ask for  +Prado's implementation of Active Record does not maintain referential identity. Each object obtained using +Active Record is a copy of the data in the database. For example, If you ask for +a particular customer and get back a <tt>Customer</tt> object, the next time you ask for  that customer you get back another instance of a <tt>Customer</tt> object. This implies that a strict  comparison (i.e., using <tt>===</tt>) will return false, while loose comparison (i.e., using <tt>==</tt>) will -return true if the object values are equal by loose comparison.  +return true if the object values are equal by loose comparison.  <p>  <p>  This is design implication related to the following question. -<i>"Do you think of the customer as an object, of which there's only one,  +<i>"Do you think of the customer as an object, of which there's only one,  or do you think of the objects you operate on as <b>copies</b> of the database?"</i> -Other O/R mappings will imply that there is only one Customer object with custID 100, and it literally is that customer.  -If you get the customer and change a field on it, then you have now changed that customer.  -<i>"That constrasts with: you have changed this copy of the customer, but not that copy.  -And if two people update the customer on two copies of the object, whoever updates first,  +Other O/R mappings will imply that there is only one Customer object with custID 100, and it literally is that customer. +If you get the customer and change a field on it, then you have now changed that customer. +<i>"That constrasts with: you have changed this copy of the customer, but not that copy. +And if two people update the customer on two copies of the object, whoever updates first,  or maybe last, wins."</i> [A. Hejlsberg 2003]  </p> @@ -1059,6 +1059,45 @@ arrays. E.g. <tt>$player->skills[] = new SkillRecord()</tt>. If <tt>array</tt> w  will be thrown.  </p> +<h2>Column Mapping</h2> +<p> +Since v3.1.1, Active Record starts to support column mapping. Column mapping allows developers +to address columns in Active Record using a more consistent naming convention. In particular, +using column mapping, one can access a column using whatever name he likes, rather than limited by +the name defined in the database schema. +</p> +<p> +To use column mapping, declare a static array named <tt>COLUMN_MAPPING</tt> in the Active Record class. +The keys of the array are column names (called <i>physical column names</i>) as defined in the database +schema, while the values are corresponding property names (called <i>logical column names</i>) defined +in the Active Record class. The property names can be either public class member variable names or +component property names defined via getters/setters. If a physical column name happens to be the same +as the logical column name, they do not need to be listed in <tt>COLUMN_MAPPING</tt>. +</p> +<com:TTextHighlighter Language="php" CssClass="source block-content"> +class UserRecord extends TActiveRecord +{ +	const TABLE='users'; +	protected static $COLUMN_MAPPING=array +	( +		'user_id'=>'id', +		'email_address'=>'email', +		'first_name'=>'firstName', +		'last_name'=>'lastName', +	); +	public $id; +	public $username; // the physical and logical column names are the same +	public $email; +	public $firstName; +	public $lastName; +	//.... +} +</com:TTextHighlighter> +<p> +With the above column mapping, we can address <tt>first_name</tt> using <tt>$userRecord->firstName</tt> +instead of <tt>$userRecord->first_name</tt>. This helps separation of logic and model. +</p> +  <h2 id="138054">References</h2>  <ul id="u3" class="block-content">      <li>Fowler et. al. <i>Patterns of Enterprise Application Architecture</i>, | 
