Release 10.1A: OpenEdge Development:
Programming Interfaces

Writing XML Schema from a temp-table, temp-table buffer, or ProDataSet

The WRITE-XMLSCHEMA() method writes an XML representation (an XML Schema document) of the definition for a temp-table, temp-table buffer, or ProDataSet object. The XML Schema is written using the XML Schema Definition (XSD) language.

When writing XML Schema for a temp-table or temp-table buffer object, Progress writes temp-table and index definitions.When writing XML Schema for a ProDataSet object, Progress writes all temp-table definitions, index definitions, and data-relations.

Here is the syntax for WRITE-XMLSCHEMA( ). The method returns TRUE or FALSE to indicate whether the operation was successful.

Syntax

WRITE-XMLSCHEMA ( target-type,    { file | stream | memptr | handle | longchar }    [, formatted [, encoding [, min-xmlschema ] ] ] )

target-type

A CHARACTER expression that specifies the target XML Schema document type. Valid values are: “FILE”, “STREAM”, “MEMPTR”, “HANDLE”, and “LONGCHAR”.

file

A CHARACTER expression that specifies the name of a file to which Progress writes the XML Schema document text. You can specify an absolute pathname or a relative pathname (based on the current working directory). If a file with the specified name already exists, Progress verifies that the file is writeable and overwrites the file.

stream

A CHARACTER expression that specifies the name of a stream. If you specify the empty string (""), Progress writes the XML Schema document text to the default unnamed output stream.

memptr

A MEMPTR variable to contain the XML Schema document text. The method allocates the required amount of memory for the XML document text and sets the size of the variable. When you are finished using the MEMPTR, you must free the associated memory by executing SET-SIZE(memptr) = 0 on the MEMPTR.

handle

An X-document object handle or X-noderef object handle. If the specified handle contains XML text, Progress deletes the existing text first.

longchar

A LONGCHAR variable to contain the XML Schema document text.

Progress saves the XML Schema document text to the LONGCHAR variable in the code page that corresponds to the character encoding you specify in the encoding option. If you do not specify a character encoding for the XML Schema document text, Progress saves the LONGCHAR variable in UTF-8.

If the LONGCHAR variable’s code page is fixed (that is, set using the FIX-CODEPAGE function) and the fixed code page is not equivalent to the character encoding you specify in the encoding option, the WRITE-XMLSCHEMA( ) method returns an error and the XML Schema document is not saved to the LONGCHAR.

formatted

An optional LOGICAL expression where TRUE directs Progress to format the XML Schema document text in a hierarchical manner using extra white space, carriage returns, and line feeds. The default value is FALSE.

If you specify the Unknown value (?), the method uses the default value of FALSE.

encoding

An optional CHARACTER expression that specifies the name of the character encoding Progress uses to write the XML Schema document text. The default encoding is UTF-8.

The encoding name must be an Internet Assigned Numbers Authority (IANA) name supported by the Progress XML Parser. For a list of supported IANA encodings and their corresponding Progress code pages, see Appendix D "XML Reference of Data Type and Code Page mappings."

Note: Progress records this character encoding in the encoding declaration in the XML document’s prologue. If you specify the empty string ("") or the Unknown value (?), Progress uses the default encoding of UTF-8. In this case, Progress does not record the character encoding in the XML document’s encoding declaration.

If target-type is HANDLE, the X-document’s ENCODING attribute is also set.

min-xmlschema

An optional LOGICAL expression where TRUE directs Progress to write the minimum amount of XML Schema for the object, and FALSE directs Progress to write the complete XML Schema including Progress-specific XML Schema attributes. The default value is FALSE. If you specify the Unknown value (?), the method uses the default value of FALSE.

When TRUE, Progress-specific XML Schema information is omitted from the XML Schema. For a complete list of progress XML Schema extensions, see "Using XML Schema" section. If the Progress data type of the temp-table field is not the default Progress data type for the XML Schema type, Progress writes the prodata:dataType XML Schema attribute for the field. If the initial value of the temp-table field is TODAY, NOW, or UNKNOWN (and UNKNOWN is not the default initial value for the field’s data type), Progress writes the prodata:initial XML Schema attribute for the field.