GeezerVison

Multiple-instance templates refer to the use of a series of instances of the same (wiki) template on a single wiki page, usually with unique data assigned to each instance. For instance, instances of a template may be used to list the contacts of a company, the ingredients of a recipe, the stories in a book, etc. In this way, you can present items of the same type in a uniform manner and streamline structured data so that they can be stored in the database.

The term is typically used in the context of managing such a list of template instances by way of a form (see the form extensions below) as well as itemising data to be stored in the database (see the data storage extensions below).

Structurally, multiple-instance templates can be either top-level templates or children of a parent template. A child template is an instance of a template assigned to a parameter of the parent template. A top-level template is not nested in this way and may or may not behave as a parent template for one or multiple child templates. Deeper levels of nesting templates are not impossible, but lack support in form extensions.

The ingredients of some recipe for salad :

{{Recipe
|Title=My favourite salad
|Ingredients={{Ingredient
 |Item=Romaine lettuce
 |Quantity=Four leaves.
 |Preparation=Torn.
}}{{Ingredient
 |Item=Radish
 |Quantity=Six radishes.
 |Preparation=Chopped.
}}{{Ingredient
 |Item=Tomato
 |Quantity=2 tomatoes.
 |Preparation=Chopped.
}}{{Ingredient
 |Item=Licame
 |Quantity=A small one.
 |Preparation=Peeled and julienned.
}}
}}

(etc.)

A number of extensions are available that let you use a form to manage template instances more easily.

• Extension:Page Forms: see especially this help page. The term 'multiple-instance templates' was likely coined for this extension.
• Extension:FlexForm: offers similar support. See especially this help page.

Template instances can be used as containers for structured data. The following extensions offer parser functions that can be used in a template to store data:

• Extension:Semantic MediaWiki (SMW) - offers the #subobject parser function for self-contained units of property-value pairs as well as a data type called Record.
• Extension:Cargo - offers #cargo_declare and #cargo_store, which can be used in a way similar to SMW's subobjects.

• Help:Tabular data
• Manual:Managing data in MediaWiki
• Manual:Template limits
• Extension:TemplateFunc

• Templates