> To define an Item Type Library implicitly defines an EC Schema?
Yes.
> Is the schema that it defines a first-class schema, equivalent to a schema defined any other way?
Yes, to workflows which operate on ECSchemas, Item Type Libraries look like any other ECSchema. e.g., Reporting, Explorer, etc.
> That is, do we lose any capability by creating an Item Type Library?
You lose some capabilities and gain others.
An Item Type Library supports a subset of the features supported by hand-rolled ECSchemas, for two reasons:
1. We wanted to simplify some EC concepts so the average user can comprehend and use them (if you have used Class Editor, you are have some inkling of how complicated ECSchemas can become).
2. We needed to simplify things in order to design a usable user interface around editing schemas (I do not consider Class Editor a user-friendly interface).
Some EC features not (currently) supported by Item Types:
- Class inheritance
- Nested structs
- ECRelationship classes
- Calculated properties (very much desired though)
- Read-only properties
- Non-standard schema references (i.e. each Item Type Library is self-contained)
Some capabilities only available for Item Types:
- Attach/Detach Item tool
- Ability to create/edit within MicroStation
- Ability to import from dgnlibs
- Integration with parametric modeling via Variables dialog
Neither of these is a comprehensive list.
HTH,
Paul
Yes.
> Is the schema that it defines a first-class schema, equivalent to a schema defined any other way?
Yes, to workflows which operate on ECSchemas, Item Type Libraries look like any other ECSchema. e.g., Reporting, Explorer, etc.
> That is, do we lose any capability by creating an Item Type Library?
You lose some capabilities and gain others.
An Item Type Library supports a subset of the features supported by hand-rolled ECSchemas, for two reasons:
1. We wanted to simplify some EC concepts so the average user can comprehend and use them (if you have used Class Editor, you are have some inkling of how complicated ECSchemas can become).
2. We needed to simplify things in order to design a usable user interface around editing schemas (I do not consider Class Editor a user-friendly interface).
Some EC features not (currently) supported by Item Types:
- Class inheritance
- Nested structs
- ECRelationship classes
- Calculated properties (very much desired though)
- Read-only properties
- Non-standard schema references (i.e. each Item Type Library is self-contained)
Some capabilities only available for Item Types:
- Attach/Detach Item tool
- Ability to create/edit within MicroStation
- Ability to import from dgnlibs
- Integration with parametric modeling via Variables dialog
Neither of these is a comprehensive list.
HTH,
Paul