XSD - how to allow elements in any order any number of times

Question

I am trying to create an XSD  and trying to write the definition with the following requirement    Allow child element specified to appear any number of times  0 to unbounded  Allow child elements to be in any order   I looked around and found various solutions like this    lt xs element name  foo  gt     lt xsl complexType gt       lt xs choice minOccurs  0  maxOccurs  unbounded  gt         lt xs element name  child1  type  xs int   gt         lt xs element name  child2  type  xs string   gt       lt  xs choice gt     lt  xs complexType gt   lt  xs element gt    But from what I understand xs choice still only allows single element selection  Hence setting the MaxOccurs to unbounded  like this should only mean that  any one  of the child elements can appear multiple times  Is this accurate    If above solution is incorrect  how can I achieve what I stated above in my requirement   EDIT  What if the requirement is as follows    Element child1 child2 can appear any number of times  0 to unbounded  Elements to be in any order Elements child3 and child4 should appear exactly once    For example   this xml is valid    lt foo gt   lt child1 gt  value  lt  child1 gt   lt child1 gt  value  lt  child1 gt   lt child3 gt  value  lt  child3 gt   lt child2 gt  value  lt  child2 gt   lt child4 gt  value  lt  child4 gt   lt child1 gt  value  lt  child1 gt   lt  foo gt    but this is not  missing child3    lt foo gt   lt child1 gt  value  lt  child1 gt   lt child1 gt  value  lt  child1 gt   lt child2 gt  value  lt  child2 gt   lt child4 gt  value  lt  child4 gt   lt child1 gt  value  lt  child1 gt   lt  foo gt

User · Answer

If none of the above is working  you are probably working on EDI trasaction where you need to validate your result against an HIPPA schema or any other complex xsd for that matter  The requirement is that  say there 8 REF segments and any of them have to appear in any order and also not all are required  means to say you may have them in following order 1st REF  3rd REF   2nd REF  9th REF  Under default situation EDI receive will fail  beacause default complex type is    lt xs sequence gt     lt xs element     gt   lt  xs sequence gt    The situation is even complex when you are calling your element by refrence and then that element in its original spot is quite complex itself  for example    lt xs element gt   lt xs complexType gt   lt xs sequence gt   lt element name  REF1   ref   REF1 Mycustomelment  minOccurs  0  maxOccurs  1  gt   lt element name  REF2   ref   REF2 Mycustomelment  minOccurs  0  maxOccurs  1  gt   lt element name  REF3   ref   REF3 Mycustomelment  minOccurs  0  maxOccurs  1  gt   lt  xs sequence gt   lt  xs complexType gt   lt  xs element gt    Solution   Here simply replacing  sequence  with  all   or using  choice  with min max combinations won t work   First thing replace  xs sequence  with   lt xs all gt   Now You need to make some changes where you are Referring the element from  There go to    lt xs annotation gt     lt xs appinfo gt       lt b recordinfo structure  delimited  field         Biztalk 2003  gt       Now in the above segment add trigger point in the end like this trigger field  REF01    complete name    trigger value    38   Do the same for other REF segments where trigger value will be different like say  18    XX     YY  etc  so that your record info now looks like b recordinfo structure  delimited  field         Biztalk 2003  trigger field  REF01    complete name    trigger value  38  gt     This will make each element unique  reason being All REF segements  above example  have same structure like REF01  REF02  REF03  And during validation the structure validation is ok but it doesn t let the values repeat because it tries to look for remaining values in first REF itself  Adding triggers will make them all unique and they will pass in any order and situational cases  like use 5 out 9 and not all 9 9    Hope it helps you  for I spent almost 20 hrs on this   Good Luck

User · Answer

This is what finally worked for me    lt xsd element name  bar  gt     lt xsd complexType gt       lt xsd sequence gt         lt  --  Permit any of these tags in any order in any number     -- gt         lt xsd choice minOccurs  0  maxOccurs  unbounded  gt           lt xsd element name  child1  type  xsd string    gt           lt xsd element name  child2  type  xsd string    gt           lt xsd element name  child3  type  xsd string    gt         lt  xsd choice gt       lt  xsd sequence gt     lt  xsd complexType gt   lt  xsd element gt

User · Answer

The alternative formulation of the question added in a later edit seems still to be unanswered   how to specify that among the children of an element  there must be one named child3  one named child4  and any number named child1 or child2  with no constraint on the order in which the children appear   This is a straightforwardly definable regular language  and the content model you need is isomorphic to a regular expression defining the set of strings in which the digits  3  and  4  each occur exactly once  and the digits  1  and  2  occur any number of times   If it s not obvious how to write this  it may help to think about what kind of finite state machine you would build to recognize such a language   It would have at least four distinct states      an initial state in which neither  3  nor  4  has been seen an intermediate state in which  3  has been seen but not  4  an intermediate state in which  4  has been seen but not  3  a final state in which both  3  and  4  have been seen   No matter what state the automaton is in   1  and  2  may be read  they do not change the machine s state   In the initial state   3  or  4  will also be accepted  in the intermediate states  only  4  or  3  is accepted  in the final state  neither  3  nor  4  is accepted   The structure of the regular expression is easiest to understand if we first define a regex for the subset of our language in which only  3  and  4  occur    34   43    To allow  1  or  2  to occur any number of times at a given location  we can insert  1 2    or  12   if our regex language accepts that notation    Inserting this expression at all available locations  we get    1 2    3 1 2  4   4 1 2  3   1 2     Translating this into a content model is straightforward   The basic structure is equivalent to the regex  34   43     lt xsd complexType name  paul0  gt     lt xsd choice gt       lt xsd sequence gt         lt xsd element ref  child3   gt         lt xsd element ref  child4   gt       lt  xsd sequence gt       lt xsd sequence gt         lt xsd element ref  child4   gt         lt xsd element ref  child3   gt       lt  xsd sequence gt     lt  xsd choice gt   lt  xsd complexType gt    Inserting a zero-or-more choice of child1 and child2 is straightforward    lt xsd complexType name  paul1  gt     lt xsd sequence gt       lt xsd choice minOccurs  0  maxOccurs  unbounded  gt         lt xsd element ref  child1   gt         lt xsd element ref  child2   gt       lt  xsd choice gt             lt xsd choice gt         lt xsd sequence gt           lt xsd element ref  child3   gt           lt xsd choice minOccurs  0  maxOccurs  unbounded  gt             lt xsd element ref  child1   gt             lt xsd element ref  child2   gt           lt  xsd choice gt                 lt xsd element ref  child4   gt         lt  xsd sequence gt         lt xsd sequence gt           lt xsd element ref  child4   gt           lt xsd choice minOccurs  0  maxOccurs  unbounded  gt             lt xsd element ref  child1   gt             lt xsd element ref  child2   gt           lt  xsd choice gt                 lt xsd element ref  child3   gt         lt  xsd sequence gt       lt  xsd choice gt       lt xsd choice minOccurs  0  maxOccurs  unbounded  gt         lt xsd element ref  child1   gt         lt xsd element ref  child2   gt       lt  xsd choice gt           lt  xsd sequence gt   lt  xsd complexType gt    If we want to minimize the bulk a bit  we can define a named group for the repeating choices of child1 and child2    lt xsd group name  onetwo  gt     lt xsd choice gt       lt xsd element ref  child1   gt       lt xsd element ref  child2   gt     lt  xsd choice gt      lt  xsd group gt    lt xsd complexType name  paul2  gt     lt xsd sequence gt       lt xsd group ref  onetwo  minOccurs  0  maxOccurs  unbounded   gt       lt xsd choice gt         lt xsd sequence gt           lt xsd element ref  child3   gt           lt xsd group ref  onetwo  minOccurs  0  maxOccurs  unbounded   gt           lt xsd element ref  child4   gt         lt  xsd sequence gt         lt xsd sequence gt           lt xsd element ref  child4   gt           lt xsd group ref  onetwo  minOccurs  0  maxOccurs  unbounded   gt           lt xsd element ref  child3   gt         lt  xsd sequence gt       lt  xsd choice gt         lt xsd group ref  onetwo  minOccurs  0  maxOccurs  unbounded   gt     lt  xsd sequence gt   lt  xsd complexType gt    In XSD 1 1  some of the constraints on all-groups have been lifted  so it s possible to define this content model more concisely    lt xsd complexType name  paul3  gt     lt xsd all gt       lt xsd element ref  child1  minOccurs  0  maxOccurs  unbounded   gt       lt xsd element ref  child2  minOccurs  0  maxOccurs  unbounded   gt       lt xsd element ref  child3   gt       lt xsd element ref  child4   gt           lt  xsd all gt   lt  xsd complexType gt    But as can be seen from the examples given earlier  these changes to all-groups do not in fact change the expressive power of the language  they only make the definition of certain kinds of languages more succinct

User · Answer

You should find that the following schema allows the what you have proposed      lt xs element name  foo  gt       lt xs complexType gt         lt xs sequence minOccurs  0  maxOccurs  unbounded  gt           lt xs choice gt             lt xs element maxOccurs  unbounded  name  child1  type  xs unsignedByte    gt             lt xs element maxOccurs  unbounded  name  child2  type  xs string    gt           lt  xs choice gt         lt  xs sequence gt       lt  xs complexType gt     lt  xs element gt    This will allow you to create a file such as    lt  xml version  1 0  encoding  utf-8    gt   lt foo gt     lt child1 gt 2 lt  child1 gt     lt child1 gt 3 lt  child1 gt     lt child2 gt test lt  child2 gt     lt child2 gt another-test lt  child2 gt   lt  foo gt    Which seems to match your question

User · Answer

In the schema you have in your question  child1 or child2 can appear in any order  any number of times  So this sounds like what you are looking for   Edit  if you wanted only one of them to appear an unlimited number of times  the unbounded would have to go on the elements instead   Edit  Fixed type in XML   Edit  Capitalised O in maxOccurs   lt xs element name  foo  gt      lt xs complexType gt        lt xs choice maxOccurs  unbounded  gt          lt xs element name  child1  type  xs int  maxOccurs  unbounded   gt          lt xs element name  child2  type  xs string  maxOccurs  unbounded   gt        lt  xs choice gt      lt  xs complexType gt   lt  xs element gt

User · Answer

But from what I understand xs choice still only allows single element selection  Hence setting the MaxOccurs to unbounded like this should only mean that  any one  of the child elements can appear multiple times  Is this accurate    No  The choice happens individually for every  repetition  of xs choice that occurs due to maxOccurs  unbounded   Therefore  the code that you have posted is correct  and will actually do what you want as written

[xml] XSD - how to allow elements in any order any number of times?

Examples related to xml

Examples related to xsd