Understanding How the XML Engine Works

The XML engine works much like other SAS engines. That is, you execute a LIBNAME statement in order to assign a libref and specify an engine. You then use that libref throughout the SAS session where a libref is valid.

However, instead of the libref being associated with the physical location of a SAS library, the libref for the XML engine is associated with a physical location of an XML document. When you use the libref that is associated with an XML document, SAS either translates the data in a SAS data set into XML markup or translates the XML markup into SAS format.

To import an XML document as a SAS data set, the following LIBNAME statement assigns a libref to a specific XML document and specifies the XML engine:

libname myxml xml 'C:\My Files\XML\Students.xml';

Executing the DATASETS procedure shows that SAS interprets the XML document as a SAS data set:

proc datasets library=myxml;

PROC DATASETS Output for MYXML Library

                                            Directory

          Libref         MYXML
          Engine         XML
          Physical Name  C:\My Files\XML\Students.xml
          XMLType        GENERIC
          XMLMap         NO XMLMAP IN EFFECT


                                                    Member
                                       #  Name      Type

                                       1  STUDENTS  DATA

The PRINT procedure results in the following output:

proc print data=myxml.students;
run;

PROC PRINT Output of SAS Data Set MYXML.STUDENTS

                              The SAS System      

    Obs    STATE     CITY          ADDRESS           NAME                  ID

      1    Texas     Huntsville    1611 Glengreen    Brad Martin          755
      2    Texas     Houston       11900 Glenda      Zac Harvell         1522

To export an XML document from a SAS data set, the LIBNAME statement for the XML engine assigns a libref to an XML document to be created from a SAS data set.

In the following code, the first LIBNAME statement assigns the libref MYFILES to the SAS library that contains the SAS data set Singers. The second LIBNAME statement assigns the libref MYXML to the physical location of the XML document that is to be exported from Myfiles.Singers:

libname myfiles 'C:\My Files\';

libname myxml xml 'C:\My Files\XML\Singers.xml';

Executing these statements creates the XML document named Singers.XML:

data myxml.Singers;
   set myfiles.Singers;
run;

XML Document Singers.XML

<?xml version="1.0" encoding="windows-1252" ?>
<TABLE>
   <SINGERS>
      <FirstName> Tom </FirstName>
      <Age> 62 </Age>
   </SINGERS>
   <SINGERS>
      <FirstName> Willie </FirstName>
      <Age> 70 </Age>
   </SINGERS>
   <SINGERS>
      <FirstName> Randy </FirstName>
      <Age> 43 </Age>
   </SINGERS>
</TABLE>

Copyright © 2007 by SAS Institute Inc., Cary, NC, USA. All rights reserved.