Class Attribute Reference

This page is a full reference for the class-level attributes available in Cognibase.

Attribute Hierarchy

SecurityObjectAttribute
└── RuntimeClassAttribute          [RuntimeClass]
    └── PersistedClassAttribute    [PersistedClass]

PersistedClassAttribute inherits all options from RuntimeClassAttribute, which in turn inherits security options from SecurityObjectAttribute.

[PersistedClass]

Applied to classes that are saved to the database and synchronized across all nodes.

[PersistedClass]
public class Order : DataItem { ... }

Persistence Options

Option	Type	Default	Description
PersistedAs	string	(class name)	Override the database table name
IsArchivable	bool	false	Enables the archival workflow for instances of this class
IsClientPreLoaded	bool	false	Instructs the Client Object Manager to load all instances of this class automatically on startup
IsServerPreLoaded	bool	false	Instructs the Server Object Manager to load all instances of this class automatically on startup
TrackExactRefByChanges	bool	false	Enables precise tracking of reverse references
IdPersistenceMode	DataItemIdPersistenceMode	Default	Controls how this class's identity key is stored

Example — Class with Storage Options

// Loaded on both client and server at startup; stored in a custom table name
[PersistedClass(
    PersistedAs = "tbl_screen",
    IsClientPreLoaded = true,
    IsServerPreLoaded = true)]
public class Screen : DataItem
{
    [PersistedProperty(IdOrder = 1, AutoValue = AutoValue.Identity)]
    public long Id { get => getter<long>(); set => setter(value); }

    [PersistedProperty(IsMandatory = true)]
    public string HostAddress { get => getter<string>(); set => setter(value); }

    [PersistedProperty]
    public int Width { get => getter<int>(); set => setter(value); }

    [PersistedProperty]
    public int Height { get => getter<int>(); set => setter(value); }
}

[RuntimeClass]

Applied to classes that are synchronized across all nodes but are never saved to the database, as they are only in-memory stored.

[RuntimeClass]
public class LiveAlert : DataItem { ... }

[PersistedClass] inherits all options listed below, so these apply to both attribute types.

Behaviour Options

Option	Type	Default	Description
IsTemplate	bool	false	Marks the class as a template — not directly instantiated
Description	string	""	Human-readable description of the class
IsClientCached	bool	false	Cache instances on the client
IsServerCached	bool	false	Cache instances on the server
IsNotifyingReferrersOnChange	bool	false	When a property changes, notify all objects that hold a reference to this object
HasRuleViolations	bool	true	Enables the rule-violation framework for this class
IsSafeInsert	bool	true	Use safe-insert semantics when creating new instances

Display and Binding Options

Option	Type	Default	Description
ClassDisplayMode	DeclarativePropertyDisplayMode	ScalarAndReferences	Controls which properties are surfaced in auto-generated UI
ClassBindMode	DeclarativePropertyBindMode	ScalarAndReferences	Controls which properties participate in auto data-binding
SignatureMode	SignatureMode	Default	How the object's signature string is composed
SignaturePrefix	string	null	Prefix added before the signature string
SignatureSuffix	string	null	Suffix added after the signature string
SignatureSeparator	string	null	Separator used between signature components
DisplaySettingsHandlerMethodName	string	null	Name of the method that returns display settings for this object

Collision and Change-Stream Options

Option	Type	Default	Description
ReferenceByHandlingMode	ReferenceByHandlingMode	Delegate	How reference-by relationships are handled
ChangeStreamMode	ChangeStreamMode	Delegate	Streaming behaviour for change events
CollisionClientHandlingMode	CollisionClientHandlingMode	Delegate	How the client resolves concurrent edit collisions
CollisionServerHandlingMode	CollisionServerHandlingMode	Delegate	How the server resolves concurrent edit collisions

Field Load Error Options

Option	Type	Default	Description
FieldLoadErrorMonitorMode	FieldLoadErrorMonitorMode	On	Whether field-load errors are monitored
FieldLoadErrorReportMode	FieldLoadErrorReportMode	Delegate	How field-load errors are reported
FieldLoadErrorValueDeliveryMode	FieldLoadErrorValueDeliveryMode	Delegate	What value is delivered when a field-load error occurs
FieldLoadAgingMode	FieldLoadAgingMode	Delegate	How field aging is applied on this class
FieldLoadAgingDelay	string	""	Delay duration for field aging

Security Options (inherited from SecurityObjectAttribute)

Option	Type	Default	Description
SecurityEnabled	bool	true	Whether security checks are evaluated for this class
SecurityLabel	string	""	Label shown for this object in security management UI
SecurityHeader	string	""	Column header shown in security lists
SecurityDescription	string	""	Description shown in security management UI
SecurityDisplayOrder	int	0	Sort order in security management lists

Per-operation security defaults (all bool, all default true):

• SecurityDefaultLoadAllow
• SecurityDefaultBrowseAllow
• SecurityDefaultDisplayAllow
• SecurityDefaultSaveNewAllow
• SecurityDefaultSaveUpdatedAllow
• SecurityDefaultSaveDeletedAllow
• SecurityDefaultSaveArchivedAllow
• SecurityDefaultFieldDisplayAllow
• SecurityDefaultFieldChangeAllow
• SecurityDefaultActionExecuteAllow
• SecurityDefaultDataLoadAllow
• SecurityDefaultDataBrowseAllow
• SecurityDefaultDataDisplayAllow

Example — Runtime Class with Security

[RuntimeClass(
    Description = "Live operational status of a display screen",
    IsClientCached = true,
    SecurityOnFields = true,
    SecurityDefaultFieldChangeAllow = false)]  // fields are read-only by default
public class ScreenStatus : DataItem
{
    [RuntimeProperty]
    public bool IsOnline { get => getter<bool>(); set => setter(value); }

    [RuntimeProperty]
    public string ActiveContentName { get => getter<string>(); set => setter(value); }

    [RuntimeProperty]
    public DateTime LastHeartbeat { get => getter<DateTime>(); set => setter(value); }
}

Abstract Classes

You can mark any DataItem subclass as abstract. The class still carries [PersistedClass] or [RuntimeClass], but cannot be instantiated directly. Concrete subclasses inherit all annotated properties:

// Abstract base — defines shared structure
[PersistedClass]
public abstract class MediaFile : DataItem
{
    [PersistedProperty(IdOrder = 1, AutoValue = AutoValue.Identity)]
    public long Id { get => getter<long>(); set => setter(value); }

    [PersistedProperty(IsMandatory = true)]
    public string FileName { get => getter<string>(); set => setter(value); }

    [PersistedProperty]
    public long FileSizeBytes { get => getter<long>(); set => setter(value); }
}

// Concrete subclass — adds image-specific fields
[PersistedClass]
public class ImageFile : MediaFile
{
    [PersistedProperty]
    public int PixelWidth { get => getter<int>(); set => setter(value); }

    [PersistedProperty]
    public int PixelHeight { get => getter<int>(); set => setter(value); }

    [PersistedProperty]
    public ImageBLOB Thumbnail { get => getter<ImageBLOB>(); set => setter(value); }
}

// Concrete subclass — adds video-specific fields
[PersistedClass]
public class VideoFile : MediaFile
{
    [PersistedProperty]
    public TimeSpan Duration { get => getter<TimeSpan>(); set => setter(value); }

    [PersistedProperty]
    public BLOB Data { get => getter<BLOB>(); set => setter(value); }
}

A property typed as MediaFile can hold a reference to an ImageFile or a VideoFile instance:

[PersistedClass]
public class PlaylistItem : DataItem
{
    [PersistedProperty(IdOrder = 1, AutoValue = AutoValue.Identity)]
    public long Id { get => getter<long>(); set => setter(value); }

    // Can reference any concrete MediaFile subtype
    [PersistedProperty(IsMandatory = true)]
    public MediaFile File { get => getter<MediaFile>(); set => setter(value); }
}

Non-Compressible Classes

By default, Cognibase may compress object payloads during network transfer. To opt a class out of compression — for example because it already stores compressed binary data — apply [NonCompressible]:

[NonCompressible]
[PersistedClass]
public class VideoClipFile : MediaFile
{
    [PersistedProperty]
    public BLOB CompressedData { get => getter<BLOB>(); set => setter(value); }
}

Custom Persistence Provider

If you need to override how a class's data is stored and retrieved (e.g. to map it against a legacy schema or an external API), implement ICustomPersistenceProvider and attach it with [PersistWith]:

[PersistWith(PersistenceProviderType = typeof(LegacyOrderPersistenceProvider))]
[PersistedClass]
public class LegacyOrder : DataItem
{
    [PersistedProperty(IdOrder = 1)]
    public string OrderNumber { get => getter<string>(); set => setter(value); }
    // ...
}