Data Subscriptions: Creation API Overview

Subscription creation is accessible through DocumentStore's Subscriptions Property, of type DocumentSubscriptions:

string Create(SubscriptionCreationOptions options, string database = null);
string Create<T>(Expression<Func<T, bool>> predicate = null, SubscriptionCreationOptions options = null, string database = null);
string Create<T>(SubscriptionCreationOptions<T> options, string database = null);

Task<string> CreateAsync(SubscriptionCreationOptions options, string database = null, CancellationToken token = default);
Task<string> CreateAsync<T>(Expression<Func<T, bool>> predicate = null, SubscriptionCreationOptions options = null, string database = null, CancellationToken token = default);
Task<string> CreateAsync<T>(SubscriptionCreationOptions<T> options, string database = null, CancellationToken token = default);

Non generic version of the class, relies on user's full knowledge of the RQL query structure

An RQL statement will be built based on the fields.

All subscriptions, are eventually translated to an RQL-like statement. These statements has four parts:

• Functions definition part, like in ordinary RQL. Those functions can contain any javascript code, and also supports load and include operations.

• From statement, defining the documents source, ex: from Orders. The from statement can only address collections, therefore, indexes are not supported.

• Where statement describing the criteria according to which it will be decided to either send the documents to the worker or not. Those statements supports either RQL like equality operations (=, ==) ,
  plain JavaScript expressions or declared function calls, allowing to perform complex filtering logic.
  The subscriptions RQL does not support any of the known RQL searching keywords.

• Select statement, that defines the projection to be performed. The select statements can contain function calls, allowing complex transformations.

• Include statement allowing to define include path in document.

from Orders as o
where o.Lines[].Product = "products/1-A"

declare function filterLines(doc, productId)
{
    if (!!doc.Lines){
        return doc.Lines.filter(x=>x.Product == productId).length >0;
    }
    return false;
}

from Orders as o
where filterLines(o, "products/1-A")