--- title: Metadata Plus slug: commerce-connect-14/docs/metadata-plus docTags: createdAt: 2026-07-23T10:25:34.040Z --- MDP lets you extend any system object with a series of meta-fields. It is similar to object-oriented programming. For example, in object-oriented programming, you can create a base Order class, and then a **Purchase Order Type** object called PurchaseOrder, which inherits its properties and adds specific fields. The root meta-class is based on a database table called *system meta-class*. Consider that an abstract meta-class which you must extend to use when associating extended new attributes with a new meta-class. Order becomes a system meta-class, and PurchaseOrder becomes a meta-class that you can extend. The instance of the meta-class that holds values is called meta-object. | Name | Description | | --------------------- | ----------------- | | Binary | MSSQL Common Type | | Bit | MSSQL Common Type | | Char | MSSQL Common Type | | DateTime | MSSQL Common Type | | Decimal | MSSQL Common Type | | Float | MSSQL Common Type | | Image | MSSQL Common Type | | Int | MSSQL Common Type | | Money | MSSQL Common Type | | NChar | MSSQL Common Type | | NText | MSSQL Common Type | | NVarChar | MSSQL Common Type | | Real | MSSQL Common Type | | UniqueIdentifier | MSSQL Common Type | | SmallDateTime | MSSQL Common Type | | SmallInt | MSSQL Common Type | | SmallMoney | MSSQL Common Type | | Text | MSSQL Common Type | | Timestamp | MSSQL Common Type | | TinyInt | MSSQL Common Type | | VarBinary | MSSQL Common Type | | VarChar | MSSQL Common Type | | Variant | MSSQL Common Type | | Numeric | MSSQL Common Type | | Sysname | MSSQL Common Type | | Integer | Metadata Type | | Boolean | Metadata Type | | Date | Metadata Type | | Email | Metadata Type | | URL | Metadata Type | | ShortString | Metadata Type | | LongString | Metadata Type | | LongHtmlString | Metadata Type | | DictionarySingleValue | Metadata Type | | DictionaryMultiValue | Metadata Type | | EnumSingleValue | Metadata Type | | EnumMultiValue | Metadata Type | | StringDictionary | Metadata Type | | File | Metadata Type | | ImageFile | Metadata Type | | MetaObject | Metadata Type | Not all properties have a visual designer associated with them, but you can use all of them to extend the meta-class. The MDP is designed to give the resulting database structure the fastest performance. When a meta-class is created, the container data table and history tables are created with a corresponding set of stored procedures and full text indexes (if full text functionality is enabled). The appropriate indexes are also put. ## Meta-fields and Meta-classes ### Meta-fields Meta-fields describe different properties associated with an element inside Optimizely Customized Commerce. You can create a meta-field of any type supported by Metadata Plus. ### Meta-classes Customized Commerce uses meta-classes to describe different types of elements, such as Categories and Products, that are used in the creation and extension of the Customized Commerce solutions developed. Meta-class is a collection of meta-fields. The following types of meta-classes are defined: - Mediachase.MetaDataPlus.System. Used for the built-in OrderGroup elements of Customized Commerce. - Mediachase.MetaDataPlus.User. Created when a user defines a new meta-class for a OrderGroup. It is always an extension of one the existing System meta-classes. ### Use meta-classes and meta-fields It is important to understand the concepts of a meta-class and meta-field, which form the basis for purchase orders and subscriptions, to fully understand how they work within Optimizely Customized Commerce. For a better understanding, consider an example of creating a new order type WorkOrder which has the following properties: - Hours - Matrials - Bid - FinalPrice To duplicate this product inside your solution, create a WorkOrder meta-class with the OrderGroup meta-class as its parent. In this example, WorkOrder is of type Mediachase.MetaDataPlus.User, and the built-in OrderGroup meta-class is of type Mediachase.MetaDataPlus.System. Next, assign the properties to your WorkOrderClass by creating a meta-attribute for each Property, then assigning them to your WorkOrderClass. For example, the Hours property could be a meta-attribute of type Integer, and FinalPrice can be a meta-attribute of type money. After you create these meta-attributes, assign them to your WorkOrderClass. ### Create meta-fields ```csharp Mediachase.MetaDataPlus.Configurator.MetaField.Create(context: OrderContext.MetaDataContext, metaNamespace: "Mediachase.Commerce.Orders.User", name: "BidPrice", friendlyName: "Bid price", description: "Bid Price", dataType: MetaDataType.Decimal, length: 17, allowNulls: true, multiLanguageValue: false, allowSearch: false, isEncrypted: false) ``` ### Update meta-fields ```csharp var metaField = Mediachase.MetaDataPlus.Configurator.MetaField.Load(OrderContext.MetaDataContext, "BidPrice"); metaField.Description = "Better desciption"; metaField.OnUpdated(); ``` ### Delete meta-fields ```csharp var metaField = Mediachase.MetaDataPlus.Configurator.MetaField.Load(OrderContext.MetaDataContext, "BidPrice"); Mediachase.MetaDataPlus.Configurator.MetaField.Delete(OrderContext.MetaDataContext, metaField.Id); ``` ### Create meta-classes ```csharp var orderGroupClass = Mediachase.MetaDataPlus.Configurator.MetaClass.Load(OrderContext.MetaDataContext, "OrderGroup"); var metaClass = Mediachase.MetaDataPlus.Configurator.MetaClass.Create(OrderContext.MetaDataContext, "WorkOrder", "Work Order", "WorkOrder", orderGroupClass, false, "Work Order" ); ``` ### Update meta-classes ```csharp var metaClass = Mediachase.MetaDataPlus.Configurator.MetaClass.Load(OrderContext.MetaDataContext, "WorkOrder"); metaClass.FriendlyName = "Work order change"; ``` ### Delete meta-classes ```csharp var metaClass = Mediachase.MetaDataPlus.Configurator.MetaClass.Load(OrderContext.MetaDataContext, "WorkOrder"); Mediachase.MetaDataPlus.Configurator.MetaClass.Delete(OrderContext.MetaDataContext, metaClass.Id); ``` ### Add meta-felds to meta-classes ```csharp var metaClass = Mediachase.MetaDataPlus.Configurator.MetaClass.Load(OrderContext.MetaDataContext, "WorkOrder"); var metaField = Mediachase.MetaDataPlus.Configurator.MetaField.Load(OrderContext.MetaDataContext, "BidPrice") ?? Mediachase.MetaDataPlus.Configurator.MetaField.Create( context: OrderContext.MetaDataContext, metaNamespace: metaClass.Namespace, name: "BidPrice", friendlyName: "Bid Price", description: "Bid Price", dataType: MetaDataType.Decimal, length: 17, allowNulls: true, multiLanguageValue: false, allowSearch: false, isEncrypted: false); if (metaClass.MetaFields.All(x => x.Id != metaField.Id)) { metaClass.AddField(metaField); } else if (!metaField.DataType.Equals(MetaDataType.Decimal)) { metaClass.DeleteField(metaField.Name); Mediachase.MetaDataPlus.Configurator.MetaField.Delete(OrderContext.MetaDataContext, metaField.Id); metaField = Mediachase.MetaDataPlus.Configurator.MetaField.Create(context: OrderContext.MetaDataContext, metaNamespace: metaClass.Namespace, name: "BidPrice", friendlyName: "Bid Price", description: "Bid Price", dataType: MetaDataType.Decimal, length: 17, allowNulls: true, multiLanguageValue: false, allowSearch: false, isEncrypted: false); metaClass.AddField(metaField); } ``` ### Remove meta-fields from meta-classes ```csharp var metaClass = Mediachase.MetaDataPlus.Configurator.MetaClass.Load(OrderContext.MetaDataContext, "WorkOrder"); metaClass.DeleteField("BidPrice"); ```