Converting between schema languages

The Generate/Convert Schema allows you to convert a DTD or Relax NG (full or compact syntax) schema or a set of XML files to an equivalent XML Schema, DTD or Relax NG (full or compact syntax) schema. Where perfect equivalence is not possible due to limitations of the target language <oXygen/> will generate an approximation of the source schema.

The conversion functionality is available from Tools Generate/Convert Schema... (Ctrl+Alt+T) from the Project view contextual menu - the action Open withGenerate/Convert Schema and from the toolbar button Generate/Convert Schema...

A schema being edited can be converted with just one click on a toolbar button if that schema can be the subject of a supported conversion.

 

Figure 4.34. Convert a schema to other schema language

Convert a schema to other schema language

The language of the source schema is specified with one of the four radio buttons of the Input panel. If the XML Documents button is selected more than one file selection is allowed in the list below the group of radio buttons in case the conversion is based on a set of XML files instead of a single file.

The language of the target schema is specified with one of the four radio buttons of the Output panel. The encoding, the maximum line width and the number of spaces for one level of indentation can be also specified in this panel.

The conversion can be further fine-tuned by specifying more advanced options available from the Advanced options button. For example if the input is a DTD and the output is an XML Schema the advanced options are:

 

Figure 4.35. Convert a schema to other schema language - advanced options

Convert a schema to other schema language - advanced options

For the Input panel:

xmlns field

specifies the default namespace, that is the namespace used for unqualified element names.

xmlns table

Each row specifies in the prefix used for a namespace in the input schema.

colon-replacement

Replaces colons in element names by the specified chars when constructing the names of definitions used to represent the element declarations and attribute list declarations in the DTD.

element-define

Specifies how to construct the name of the definition representing an element declaration from the name of the element. The specified value must contain exactly one percent character. This percent character is replaced by the name of element (after colon replacement) and the result is used as the name of the definition.

inline-attlist

Specifies not to generate definitions for attribute list declarations and instead move attributes declared in attribute list declarations into the definitions generated for element declarations. This is the default behavior when the output language is XSD.

attlist-define

This specifies how to construct the name of the definition representing an attribute list declaration from the name of the element. The specified value must contain exactly one percent character. This percent character is replaced by the name of element (after colon replacement) and the result is used as the name of the definition.

any-name

Specifies the name of the definition generated for the content of elements declared in the DTD as having a content model of ANY.

strict-any

Preserves the exact semantics of ANY content models by using an explicit choice of references to all declared elements. By default, Trang uses a wildcard that allows any element.

generate-start

Specifies whether Trang should generate a start element. DTDs do not indicate what elements are allowed as document elements. Trang assumes that all elements that are defined but never referenced are allowed as document elements.

annotation-prefix

Default values are represented using an annotation attribute prefix:defaultValue where prefix is the specified value and is bound to http://relaxng.org/ns/compatibility/annotations/1.0 as defined by the RELAX NG DTD Compatibility Committee Specification. By default, Trang will use a for prefix unless that conflicts with a prefix used in the DTD.

For the Output panel:

disable-abstract-elements

Disables the use of abstract elements and substitution groups in the generated XML Schema. This can also be controlled using an annotation attribute.

any-process-contents

One of the values: strict, lax, skip. Specifies the value for the processContents attribute of any elements. The default is skip (corresponding to RELAX NG semantics) unless the input format is dtd, in which case the default is strict (corresponding to DTD semantics).

any-attribute-process-contents

Specifies the value for the processContents attribute of anyAttribute elements. The default is skip (corresponding to RELAX NG semantics).