Magento – Usage of getSingleton() and getModel()

classmodel

Is there a set of guidelines that I can go by to decide when I should use

   mage::getModel() and mage::getSingleton()

From what I can tell it seems as though getSingleton either gets an existing instance of a model/class or, only if one does not exist, creates a new instance. Whereas getModel() creates one regardless of what exists already. Is this correct?

Assuming I have the correct understanding of these, would it not make sense to always use mage::getSingleton()! It obviously doesn't or otherwise getModel() would not be used. So when should I use each one?

What is the main benefit to using these correctly? Should it improve performance, help avoid duplication or just generally apply best practice?

Best Answer

Yes, getSingleton returns the same instance, so you do not want to use it always, but only if you can live with having the same instance.

Example of when NOT to use a singleton:

$product = Mage::getModel('catalog/product');
$product->setSku("asdfasdf");
$product->setName("First Test Product");
$product->save();

$product = Mage::getModel('catalog/product');
$product->setSku("asdfasdf2");
$product->setName("Second Test Product");
$product->save();

This creates two products. But if you used Singleton, only one product would be created, the second one would overwrite the first one.

Related Solutions

Magento – pull database data into a text field

To answer your second question first :)

The first and last name information is added via a widget:

app/code/core/Mage/Customer/Block/Widget/Name.php
app/design/frontend/base/default/template/customer/widget/name.phtml

In the registration process these are added via:

echo $this->getLayout()->createBlock('customer/widget_name')
         ->setObject($this->getFormData())
         ->setForceUseCustomerAttributes(true)->toHtml()

I guess this was done as the name can be used in many locations, registration, address and checkout. By doing this via a widget you only need once place that adds the form fields and will cut down on duplication of code.

Now onto your first question. To pass data from the database into a textbox I would suggest that you add a new function into your block for this example getPrefcentreData.

What this function would do would take your snippet of code and load the information that you need from the database.

Then in your template you can simply call something like:

<input type="text" name="your_field" id="your_field" value="<?php $this->getPrefcentreData() ?>" class="text" />

Magento – Selecting a table and column

Some comments:

Name your tables with lowercase rather, so prefscentre_options
The _init method you call on your model Ps_Prefs_Model_Prefsemail takes 1 argument, only the resource model location.

About the table, did you manually create it? Normally it is done via a installation file, I'll assume you have that.

You say in the table you have a column named prefcentreOptions_id whereas in the magento configuration you specify it to be named prefcentreoptions_id. So difference in the casing. I'd call the table prefcentre_options and call the id field entity_id field because it is quite logically already that it's the id field if it's the primary key, so it's an unnecessary long name.

Best Answer

Related Solutions

Magento – pull database data into a text field

Magento – Selecting a table and column

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