Schema Production Status

Schema Evolution

Schemas that have been released for production use in end-user workflows evolve over time as new capabilities are added and other improvements are made. To manage and track this schema evolution, schema versioning is used. See Schema Versioning and Generations for details on BIS's schema versioning strategy.

A single version of a schema that has not yet been released for production also evolves. A pre-production schema is expanded and modified as it goes through periods of development and field testing before being released for production. Also, after a schema is released into production workflows, it may become deprecated. This page describes the management and tracking of this non-version axis of schema evolution.

Motivation

The primary motivation for formally tracking the production status of schemas is to ensure they are not used contrary to the way the schema author intended. The mechanisms described on this page:

  1. Enable the schema author to clearly define the intended usage of the schema.
  2. Enable the iModel creator to clearly define the intended usage of an iModel.
  3. Provide a mechanism to ensure that the schemas in an iModel have an intended usage that is compatible with the iModel's intended usage.

ProductionStatus Custom Attribute

The intended use of a schema is tracked through the ProductionStatus CustomAttribute. The ProductionStatus CustomAttribute may be placed on any BIS schema. That CustomAttribute has a SupportedUse property that can have one of these values:

Value Meaning
Production This schema is suitable for use in production workflows. Data created using this schema will be supported long-term (possibly through transformation).
FieldTesting This schema is suitable for field testing of production workflows. Data created using this schema may not be supported long-term and may not be upgradable.
NotForProduction This schema is under development and should never be used for production workflows. Data created with this schema is not supported and may not be upgradable.
Deprecated This schema is no longer recommended for production workflows. Better alternatives exist and should be used instead.

iModel Support for ProductionStatus

The iModel ecosystem uses the ProductionStatus of schemas to determine if a schema can be loaded into an iModel.

iModel ProductionStatus Setting

To determine whether a schema with a ProductionStatus other than Production can be loaded into an iModel, the iModel technology stack needs to understand the intended use of the iModel. For this reason, every iModel contains a ProductionStatus setting that declares the suitability of the iModel for production use. The possible values for this setting correspond to those in the ProductionStatus custom attribute, although their definitions are slightly different:

Value Meaning
Production This iModel is suitable for use in production workflows.
FieldTesting This iModel is suitable for field testing of production workflows. Data contained in it may not be supported long-term.
NotForProduction This iModel is suitable for developer testing only and should never be used for production workflows. Data contained in it will not be supported long-term.
Deprecated (this value should not be used for iModels)

The iModel's ProductionStatus setting is stored in the be_prop table as follows:

Column Value
NameSpace "dgn_Db"
Name "ProductionStatus"
StrData "Production", "FieldTesting" or "NotForProduction"

The ProductionStatus value of the iModel is set when the iModel is created.

Compatibility of Schemas for iModels

At schema load time, the iModel technology confirms that the schema's ProductionStatus is compatible with the iModel's ProductionStatus. The compatibility of these settings is shown below:

iModel ProductionStatus Compatible Schema ProductionStatus
Production Production, Deprecated
FieldTesting Production, FieldTesting, Deprecated
NotForProduction Production, FieldTesting, NotForProduction, Deprecated

The attempted loading of a schema that is not compatible will result in a schema load failure.

Changing of iModel ProductionStatus

An iModel's ProductionStatus can conceptually be "downgraded" as follows:

iModel ProductionStatus Compatible Downgraded ProductionStatus
Production FieldTesting, NotForProduction
FieldTesting NotForProduction
NotForProduction (no further downgrade is possible)

In the future, the ability for a user to downgrade the ProductionStatus of an iModel will be provided.

An iModel's ProductionStatus can conceptually be upgraded as follows:

Upgraded iModel ProductionStatus Condition
Production No schemas of ProductionStatus FieldTesting or NotForProduction
FieldTesting No schemas of ProductionStatus NotForProduction
NotForProduction (not possible as upgrade)

In the future, the ability for a user to upgrade the ProductionStatus of an iModel will be provided.


Next: BIS Schema Units

Last Updated: 20 September, 2019