Cause

Event store is queried within an iteration (while, do-while, foreach, for) through IEventStore (Load, LoadAsync, AggregateStream, AggregateStreamAsync).

Reason for rule

Queries within an iteration can indicate Select N+1 issues (see, What is N+1 SELECT query issue?). This rule aids in locating such sites, supporting manual code review of violations.

How to fix violations

To fix a violation of this rule, consider using use-case specific projections, projecting over multiple streams if necessary. Otherwise remodeling aggregates might be considered.

Examples

Violates

var dict = new Dictionary<string, User>();

var issue = query.Events.AggregateStream<Issue>("Marten1001");

foreach (var i in issue.Assignees)
{
	var user = query.Events.AggregateStream<User>(i);
	dict.Add(user.Id, user);
}