xmlvalidate

Validates an XML document.

 xmlvalidate_call ::=
      xmlvalidate ( general_string_expression, [optional_parameters])
 optional_parameters ::= options_parameter 
      | returns_type
      |options_parameter returns type
 options_parameter ::= [,] option option_string
 options_string ::= basic_string_expression 
 returns_type ::= [,] returns string_type
 string_type ::=char (integer) | varchar (integer) 
     | unichar (integer) |univarchar (integer) 
     | text | unitext |image | java.lang.String

• The defaults for validation_options are:

  • dtdvalidate = See below

  • schemavalidate = no

  • schemalocation = " "

  • nonamespaceschemalocation = " "

  • xmlerror = exception

  • xmlvalid = document

• Keywords in a validation_option are not case-sensitive, but the schema_uri_list and namespace_schema_uri_list are case-sensitive.

• Refer to the document you parse or store as the subject XML document.

• The default for dtdvalidate depends on the implicit or explicit value of the schemavalidate option. If the schemavalidate option value is no, the default value of dtdvalidate is no. If the schemavalidate option value is yes, the default dtdvalidate option value is strict.

• If you specify schemavalidate = yes, you must either specify dtdvalidate = strict or omit dtdvalidate.

• If you specify dtdvalidate = no with schemavalidate = no, the document is checked for well-formedness only.

• If you specify schemavalidate = no, the clauses nonamespaceschemalocation and schemalocation are ignored.

• The values specified in the clauses nonamespaceschemalocation and schemalocation are character literals. If the Transact-SQL quoted_identifier option is off, you can choose either apostrophes (') or quotation marks (") to surround the option_string, and use the other to surround the values specified by nonamespacescemalocation and schemalocation. If the Transact-SQL quoted_identifier option is on, you must surround the option_string with apostrophes ('), and you must surround the values specified by nonamespacescemalocation and schemalocation by quotation marks (").

• nonamespaceschemalocation specifies a list of schema URIs, which overrides the list of schema uris specified in the xsi:noNameSpaceschemalocation clause in the subject XML document.

• schemalocation specifies a list of pairs, each pair consisting of a namespace name and a schema URI.

  • a namespace name is the name an xmlns attribute specifies for a namespace. http://acme.com/schemas.contract is declared as the default namespace in this example:

    <contract xmlns="http://acme.com/schemas.contract">
    

    In this example, however, it is declared as the namespace for the prefix "co":

    <co:contract xmlns:co="http://acme.com/schemas.contract">
    

    The namespace name is the URI specified in a namespace declaration itself, not the prefix.

• A schema_uri is a character string literal that contains a schema URI. The maximum length of a URI_string is 1927 characters, and it must specify http. The schema referenced by a schema_uri must be encoded as either UTF8 or UTF16.

• The dtdvalidate option values are:

  • dtdvalidate=no: No DTD or schema validation is performed; the document is checked to ensure that it is well-formed.

  • dtdvalidate=yes: The document is validated against any DTD the document specifies.

  • dtdvalidate=strict: This option depends on the schemavalidate option.

    • schemavalidate=no:

      You must specify a DTD in the subject XML document, and the document is validated against that DTD.

    • schemavalidate=yes:

      You must declare every element in the subject XML document in a DTD or a schema, and each element is validated against those declarations.

• The schemavalidate option values are:

  • If you specify schemavalidate=no, no schema validation is performed for the subject XML document.

  • If you specify schemavalidate=yes, schema validation is performed.

• The following results apply when a general_string_expression, for instance XC, is an XML document that passes the validation options specified in the option_string clause:

  • If xmlvalid specifies doc, the result of xmlvalidate is:

    convert(text, XC)
    

  • If xmlvalid specifies message, the result of xmlvalidate is this XML document:

    <xmlvalid/>
    

• The following results apply when a general_string_expression is not an XML document that passes the validation options specified in the option_string clause:

  • If the option_string specifies xmlerror=exception, an exception is raised carrying the exception message.

  • If option_string specifies xmlerror=message, an XML document of the following form is returned. E1, E2, and so forth are messages that describe the validation errors.

    <xml_validation_errors>
         <xml_validation_error>E1</xml_validation_error>
         <xml_validation_error>E2</xml_validation_error>
    ...
         <xml_validation_warning>W1</xml_validation_warning>
         <xml_vvalidation_fatal_error>E3<xml_validation_fatal_error>
    </xml_validation_errors>
    

  • If option_string specifies xmlerror=null, a null value is returned.

If the value of the xml_data_expression is not valid XML:

• If the explicit or default options specifies xmlerror=exception, an exception is raised.

• If the explicit or default options specifies xmlerror=null, a null value will be returned.

• If the explicit or default options specifies xmlerror=message, a character string containing an XML element with all the exception messages is returned. This value is valid parsed XML.

• Global variable @@error returns the error number of the last error, whether the value of xmlerror is exception, null, or message.

• If a web resource required for validation is unavailable, an exception occurs.

• If the source XML document is either invalid or not well-formed, an exception occurs. Its message describes the validation failure.

create table text_docs(xml_doc text null)

insert into text_docs
values (xmlvalidate(
  '<employee_name>John Doe</employee_name>',
  option 'dtdvalidate=yes'))
---------
(1 row inserted)

insert into text_docs
values(xmlvalidate(
  '<emp_name>John Doe</emp_name>',
option 'dtdvalidate=strict'))
--------
EXCEPTION

insert into text_docs
values(xmlvalidate(
  '<emp_name>John Doe</emp_name>'
option 'dtdvalidate=strict xmlerror=null'))
-------
null

insert into text_docs
values(xmlvalidate(
  '<emp_name>John Doe</emp_name>'
option 'dtdvalidate=strict xmlerror=message'))
--------
<xml_validation_errors>
<xml_validation_error>(1:15)Document is invalid:
  no grammar found.<xml_validation_error>
<xml_validation_error>(1:15)Document root element    "employee name",must match DOCTYPE root    "null."</xml_validation_error>
</xml_validation_errors>

insert into text_docs
values(xmlvalidate(
  '<DOCTYPE emp_name PUBLIC "http://test/dtd_emp.dtd">
  <emp_name>John Doe</emp_name>',
option 'dtdvalidate=yes'))
-------
(1 row inserted)

insert into text_docs
values(xmlvalidate(
  '<DOCTYPE emp_name PUBLIC "http://test/dtd_cust.dtd">
<emp_name>John Doe</emp_name>',
option 'dtdvalidate=yes'))
--------
EXCEPTION

insert into text_docs
values(xmlvalidate('<emp_name>John Doe</emp_name>',
  option 'schemavalidate=yes'))
-------
EXCEPTION

insert into text_docs
values(xmlvalidate(
  '<emp_name xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi: noNamespaceSchemaLocation="http://test/schema_emp.xsd">
  John Doe</emp_name>'
 option 'schemavalidate=yes'))
--------
(1 row inserted)

insert into text_docs
values(xmlvalidate(
  '<emp:emp_name xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xmlns:emp="http://test/ns_schema_emp"
   xsi: SchemaLocation="http://test/ns_schema_emp       http://test/ns_schema_emp.xsd">
  John Doe</emp:emp_name>'
 option 'schemavalidate=yes'))
--------
(1 row inserted)

insert into text_docs
values (xmlvalidate(
  '<emp_name xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:noNamespaceSchemaLocation="http://test/schema_cust.xsd">
   John Doe</emp_name>'
 option 'schemavalidate=yes'))
-------
EXCEPTION

insert into text_docs
values(xmlvalidate(
  '<emp:emp_name
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:emp="http://test/ns_schema_cust"
    xsi:schemaLocation=
       "http://test/ns_schema_cust http://test/ns_schema_cust.xsd">
    John Doe</emp:emp_name>',
   option 'schemavalidate=yes'))
------------
EXCEPTION

The validation options of xmlvalidate specify a nonamespaceschemalocation of http://test/ns_schema_emp.xsd.

The document specifies a schemaLocation of http://test/schema_cust.xsd, and the validation option in xmlvalidate specifies a schemalocation of http://test/ns_schema_emp.xsd.

This command succeeds, because the document matches the schema referenced in xmlvalidate, which overrides the schema referenced in the document.

insert into text_docs
values (xmlvalidate(
  '<emp:emp_name
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:emp="http://test/schema_emp"
    xsi:schemaLocation="http://test/ns_schema_emp          http://test/schema_cust.xsd">
    John Doe</emp:emp_name>',
   option 'schemavalidate=yes,
    schemalocation= "http://test/ns_schema_emp          http://test/ns_schema_emp.xsd"
    nonamespaceschemalocation="http://test/schema_emp.xsd" '))
-------------
(1 row inserted)

The document specifies a noNamespaceSchemaLocation of http://test/schema_cust.xsd, and the validation option in xmlvalidate specifies a nonamespaceschemalocation of http://test/ns_schema_emp.xsd.

This command fails, because the document doesn’t match the schema referenced in xmlvalidate. The document does, however, match the schema referenced in the document.

insert into text_docs
values(xmlvalidate(
  '<customer_name
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:noNamespaceSchemaLocation="http://test/schema_cust.xsd">
  John Doe</customer_name>'
  option 'schemavalidate=yes,
schemalocation="http://test/ns_schema_emp http://test/ns_schema_emp.xsd"
    nonamespaceschemalocation="http://test/schema_emp.xsd" '))
-----------
EXCEPTION

The document specifies a schemaLocation of http://test/schema_cust.xsd, and the validation option of xmlvalidate specifies a schemalocation of http://test/ns_schema_emp.xsd.

This command fails, because the document doesn’t match the schema referenced in xmlvalidate. The document does, however, match the schema referenced in the document.

insert into text_docs
values(xmlvalidate(
  '<cust:cust_name
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:cust="http://test/schema_cust"
    xsi:schemaLocation="http://test/schema_cust           http://test/schema_cust.xsd">
   John Doe</cust:cust_name>',
  option 'schemavalidate=yes,
   schemalocation="http://test/ns_schema_emp http://test/ns_schema_emp.xsd"
   nonamespaceschemalocation="http://test/schema_emp.xsd" '))
-------
(1 row inserted)