How to query multiple entities with a single QueryExpression

Question

I am trying to run a microsoft dynamics crm 4.0 query. This works as expected when I generate a QueryExpression for "ONE" specific entity as I had done before. The issue however is how do i define more than one entity so i can apply logic that i have in another method? An example or illistration would be helpful.

so what i have is in this format:

static BusinessEntityCollection GetData(CrmService service)
{
    cols = new ColumnSet();
    cols.Attributes = new string[] { "x", "y", "z"};

    FilterExpression filter = new FilterExpression();
    filter.FilterOperator = LogicalOperator.And;

    QueryExpression query = new QueryExpression();
    query.EntityName = EntityName.incident.ToString();

    // i am trying to add something like the below
    query.EntityName = EntityName.account.toString();

    query.ColumnSet = cols;
    query.Criteria = filter;

    return service.RetrieveMultiple(query);
}

The restriction I am facing is I can only query one entity and I need a solution or workaround to access and query multiple entities. Your help is much appreciated.

Answer 1

Simple answer: you can't. You could only query one entity at one time.

A query expression is used for single-object searches, for example, to search for all accounts that match certain search criteria.

See how to build queries. You have to combine multiple requests for the entities you would like to get.

The same restriction exists for FetchXML. It is basically the serialized form of a QueryExpression. See how to use FetchXML