Metadata Plus

Metadata Plus (MDP) lets you extend any system object with a series of meta-fields. The model is similar to object-oriented programming: you can create a base Order class, then create a Purchase Order Type object called PurchaseOrder that inherits the base class properties and adds specific fields.

The root meta-class is based on a database table called system meta-class. Treat this root as an abstract meta-class — extend it whenever you need to associate 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 a meta-class that holds values is called a meta-object.

Metadata Plus supports the following data types when you define meta-fields.

MSSQL common types

These types map directly to SQL Server column types:

• Binary
• Bit
• Char
• DateTime
• Decimal
• Float
• Image
• Int
• Money
• NChar
• NText
• NVarChar
• Numeric
• Real
• SmallDateTime
• SmallInt
• SmallMoney
• Sysname
• Text
• Timestamp
• TinyInt
• UniqueIdentifier
• VarBinary
• VarChar
• Variant

Metadata Plus types

These types are defined by Metadata Plus and provide higher-level semantics:

• Boolean
• Date
• DictionaryMultiValue
• DictionarySingleValue
• Email
• EnumMultiValue
• EnumSingleValue
• File
• ImageFile
• Integer
• LongHtmlString
• LongString
• MetaObject
• ShortString
• StringDictionary
• URL

Not all data types have a visual designer associated with them, but you can use any of them to extend a meta-class.

MDP is designed for fast database performance. When a meta-class is created, the container data table and history tables are created together with a set of stored procedures and full-text indexes (if full-text functionality is enabled). MDP also adds the appropriate indexes.

Meta-fields and meta-classes

Meta-fields

Meta-fields describe properties associated with an element in Optimizely Commerce Connect. Create a meta-field of any type supported by Metadata Plus.

Meta-classes

Commerce Connect uses meta-classes to describe types of elements, such as Categories and Products, used when you create and extend Commerce Connect solutions. A meta-class is a collection of meta-fields. Commerce Connect defines the following types of meta-classes:

• Mediachase.MetaDataPlus.System – Used for the built-in OrderGroup elements of Commerce Connect.
• Mediachase.MetaDataPlus.User – Created when a user defines a new meta-class for an OrderGroup. It is always an extension of one of the existing System meta-classes.

Use meta-classes and meta-fields

Meta-classes and meta-fields form the basis for purchase orders and subscriptions in Optimizely Commerce Connect. As an example, consider a new order type WorkOrder with the following properties:

• Hours
• Materials
• Bid
• FinalPrice

To replicate this order type in 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, create a meta-attribute for each property and assign it to your WorkOrderClass. For example, the Hours property could be a meta-attribute of type Integer, and FinalPrice could be a meta-attribute of type Money.

Create meta-fields

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

var metaField = Mediachase.MetaDataPlus.Configurator.MetaField.Load(OrderContext.MetaDataContext, "BidPrice");
metaField.Description = "Better description";
metaField.OnUpdated();

Delete meta-fields

var metaField = Mediachase.MetaDataPlus.Configurator.MetaField.Load(OrderContext.MetaDataContext, "BidPrice");
Mediachase.MetaDataPlus.Configurator.MetaField.Delete(OrderContext.MetaDataContext, metaField.Id);

Create meta-classes

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

var metaClass = Mediachase.MetaDataPlus.Configurator.MetaClass.Load(OrderContext.MetaDataContext, "WorkOrder");
metaClass.FriendlyName = "Work order change";

Delete meta-classes

var metaClass = Mediachase.MetaDataPlus.Configurator.MetaClass.Load(OrderContext.MetaDataContext, "WorkOrder");
Mediachase.MetaDataPlus.Configurator.MetaClass.Delete(OrderContext.MetaDataContext, metaClass.Id);

Add meta-fields to meta-classes

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

var metaClass = Mediachase.MetaDataPlus.Configurator.MetaClass.Load(OrderContext.MetaDataContext, "WorkOrder");
metaClass.DeleteField("BidPrice");