Motivating design requirements for the schema language with the default query language binding include:
| 1. |
Represent abstract patterns such as the head+body pattern. |
| 2. |
Support progressive validation. |
| 3. |
Include assertions or abstract rules from an external file. |
| 4. |
Support a one-to-one mapping between the natural-language statements and artificial-language statements. |
| 5. |
Support the generation and labelling of arcs between information items. |
Motivating design requirements for the schema language with the default query language binding do not include:
| — |
Simple specification of constraints that are simply expressed by grammar-based validation, such as Part 2 (RELAX NG) schemas or DTDs. |
| — |
Replacement of any other standard schema language for XML. |
| — |
Single-pass or streamable implementation. |
As well, certain outcomes are out-of-scope for this part of ISO/IEC 19757:
| — |
Specification of a type system. |
| — |
Generation of links between multiple occurrences of some datum across multiple documents for the purpose of consistency-checking. |