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Cratis Cratis Cratis

From Every

The every directive applies mappings to every event that affects the projection, regardless of event type. This is useful for setting common properties like last update timestamps.

Basic Syntax

Section titled “Basic Syntax”
every
  {mappings}

Simple Example

Section titled “Simple Example”
projection User => UserReadModel
  every
    LastUpdated = $eventContext.occurred
    UpdatedBy = $eventContext.eventSourceId


  from UserRegistered
    Name = name
    Email = email


  from UserEmailChanged
    Email = email

Both UserRegistered and UserEmailChanged events will set LastUpdated and UpdatedBy.

With AutoMap

Section titled “With AutoMap”

Apply AutoMap to all events:

projection Product => ProductReadModel
  every
    automap
    LastModified = $eventContext.occurred

Exclude Children

Section titled “Exclude Children”

By default, every applies to events in child collections. To exclude them:

every
  LastUpdated = $eventContext.occurred
  exclude children

This ensures child events don’t update the parent’s LastUpdated field.

Common Patterns

Section titled “Common Patterns”

Audit Fields

Section titled “Audit Fields”

Track when the projection was last modified:

every
  LastModified = $eventContext.occurred
  LastSequenceNumber = $eventContext.sequenceNumber
  LastCorrelationId = $eventContext.correlationId

Event Source Tracking

Section titled “Event Source Tracking”

Store the event source that last modified the projection:

every
  LastModifiedBy = $eventContext.eventSourceId
  LastModifiedAt = $eventContext.occurred

Version Tracking

Section titled “Version Tracking”

Track the latest event sequence:

every
  Version = $eventContext.sequenceNumber
  UpdatedAt = $eventContext.occurred

Examples

Section titled “Examples”

User Profile with Audit

Section titled “User Profile with Audit”
projection User => UserReadModel
  every
    LastUpdated = $eventContext.occurred
    LastSequenceNumber = $eventContext.sequenceNumber
    exclude children


  from UserRegistered
    Name = name
    Email = email
    CreatedAt = $eventContext.occurred


  from UserEmailChanged
    Email = email


  from UserNameChanged
    Name = name

Product with Global AutoMap

Section titled “Product with Global AutoMap”
projection Product => ProductReadModel
  every
    automap
    LastModified = $eventContext.occurred


  from ProductCreated
    IsActive = true


  from ProductDeactivated
    IsActive = false

Document Versioning

Section titled “Document Versioning”
projection Document => DocumentReadModel
  every
    CurrentVersion = $eventContext.sequenceNumber
    LastUpdated = $eventContext.occurred
    LastCorrelation = $eventContext.correlationId
    exclude children


  from DocumentCreated
    Title = title
    Content = content


  from DocumentUpdated
    Content = content


  from DocumentRenamed
    Title = title

Order with Tracking

Section titled “Order with Tracking”
projection Order => OrderReadModel
  every
    LastEventTime = $eventContext.occurred
    EventCount = $eventContext.sequenceNumber
    exclude children


  from OrderPlaced
    CustomerId = customerId
    Total = total
    Status = "Placed"


  from OrderShipped
    ShippedAt = $eventContext.occurred
    Status = "Shipped"


  from OrderDelivered
    DeliveredAt = $eventContext.occurred
    Status = "Delivered"


  children items id itemId
    from ItemAdded
      ProductId = productId
      Quantity = quantity

Scope and Application

Section titled “Scope and Application”

Parent Level Only (with exclude children)

Section titled “Parent Level Only (with exclude children)”
every
  LastUpdated = $eventContext.occurred
  exclude children

Parent events update LastUpdated, child events do not.

Including Children (default)

Section titled “Including Children (default)”
every
  LastUpdated = $eventContext.occurred

Both parent and child events update LastUpdated.

With Multiple Children

Section titled “With Multiple Children”
projection Group => GroupReadModel
  every
    LastActivity = $eventContext.occurred
    exclude children


  from GroupCreated
    Name = name


  children members id userId
    from UserAdded
      Name = userName


  children posts id postId
    from PostCreated
      Title = title

Group-level events update LastActivity, but member and post events do not.

Best Practices

Section titled “Best Practices”
  1. Use for Common Fields: Apply every for timestamps and audit fields that should update with any event
  2. Exclude Children: Use exclude children when parent and child lifecycles are independent
  3. Keep It Simple: Limit every to truly universal properties
  4. Combine with Specific Rules: Use from events for specific updates, every for universal ones
  5. AutoMap Carefully: Global AutoMap can have unintended effects; use selectively
  6. Version Tracking: Sequence numbers are ideal for optimistic concurrency control

When to Use

Section titled “When to Use”

Use every when:

  • Setting last modified timestamps
  • Tracking latest sequence numbers
  • Maintaining version counters
  • Storing correlation IDs for all events
  • Applying AutoMap universally

Avoid every when:

  • Only specific events should update a property
  • Different events require different logic
  • Children should be treated independently