[ruby-oci8-devel] About XML DB support in Ruby-OCI8

Liming Lian liming.lian at oracle.com
Tue Mar 25 23:16:44 EDT 2008


Hi Kubo,

After applying your patch for defining bind type of XMLType, I can 
successfully retrieve XML data from db by explicitly defining the select 
data as XMLType. Here is code snippet:

## SQLs for defining XMLType table and inserting XML data to the table

CREATE TABLE xml_table (key VARCHAR2(10) PRIMARY KEY, xml_column XMLType);
CREATE DIRECTORY xmldir AS path_to_folder_containing_XML_file;
INSERT INTO xml_table VALUES (1, XMLType(bfilename('XMLDIR', 'mytest.xml'),
nls_charset_id('AL32UTF8')));

## Ruby code for retrieving XML data

conn = OCI8.new(dbuser, dbpass, dbname)
cur = conn.parse('select xml_column from xml_table where key = 1')
cur.define(1, :xmltype)
cur.exec
r = cur.fetch
xml = r[0]

After that, the variable "xml" is a REXML object, so that we can 
populate it with standard REXML APIs. It is fine with this kind of 
explicitly defining XMLtype while I also find some existed code in 
lib/oci8/oci8.rb to deal with XMLType as following:

File: lib/oci8/oci8.rb
Method: make_bind_object

def make_bind_object(param)
   case param
   when Hash
       ..........
   when OCI8::Metadata::Base
        key = param.data_type
        case key
        when :named_type
          if param.type_name == 'XMLTYPE'
            key = :xmltype
          else
            param = @con.get_tdo_by_metadata(param.type_metadata)
          end
        end
      else
      .............

I am only familiar with passing Hash parameter to make_bind_object. 
Meantime, I notice method make_bind_object also accepts param of 
OCI8::Metadata::Base type.  I am wondering how to construct such 
OCI8::Metadata::Base object so that we can bind or define XMLType in a 
manner other than the one I have tried.  Any hints? Code sample is 
appreciated!

Thanks in advance!

Liming

> Here is a quick fix to fetch XMLTYPE data as REXML objects.
>
> ===================================================================
> --- ext/oci8/xmldb.c	(revision 253)
>   



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