XML to Oracle for Newby

Question

Hi,
im a newby in Oracle related Stuff and want to read in several XML files into a table.
In the Documentation ive found this:
Working with XML
Getting data into an XMLType table and column. As you may expect, there are many options available to us to get XML data into the database. Data can be inserted with SQL, PL/SQL, Java, and C programs. We can also load data into the database using the SQL*Loader and Import/Export functions of XMLType tables. XML data can also be moved with Oracle Streams and can also use DBMS_XDB functions. Let’s explore one useful and simple way to load XML data.
In this example, an XML document will be loaded from a file into a table using a SQL insert to load the XML document from a bfile. This file needs to be accessed through a database directory. To begin this, we’ll create a directory pointing to a file where the XML document file is stored. Note that to perform the examples in this article, you must ensure that role xdbadmin has been granted to the user you are working with.
create or replace directory xmldir as '/u01/app/oracle/admin/db01/sql';
Now we can create tables that can contain XMLType data in two ways. The first will be a table with a column of XMLType. The second will be a table defined as type XMLType.
1. Create a table with an XML column.
create table invoiceXML_col (
inv_id number primary key,
inv_doc XMLType);
2. Create an XML table.
create table invoiceXML_tbl of XMLtype;
Each of the above statements implicitly creates two indexes in each table—one for the primary key and one for the LOB.
Now we will insert an invoice document into both tables. Note that we are using character set AL32UTF8 and will specify this to pass the character set encoding to be used for the file being read. Data will be inserted into both tables to show the similarity between the SQL statements.
But i dont really understand what is happening here.
Can someone here please explain me stepby step how to read in one XML file (with PL/SQL or Java) and put it into a table.
Thx

Answer 1

The simple stuff. A XML doc can be stored in its native format (plain text file) in Oracle as a CLOB. It an be stored as a parsed XML DOM (Document Object Model) as XMLTYPE.
Loading a XML file can be done using SQL*Loader - where the data file that you load contains the name of the XML file. Example of the control file for the loader:
LOAD DATA
INFILE 'mydatafile.csv'
INTO TABLE my_xml_table
FIELDS TERMINATED BY ','
filename CHAR(200),
xmlfile_content LOBFILE(filename) TERMINATED BY EOF
)And the CSV file will contain a single value per line, where the value is the (path and) name of the XML file to load. This method is typically used from client platforms to load data into the Oracle server.
Or when the file is on the Oracle Server itself, you can use DBMS_LOB to load it. Example:
create or replace procedure LoadDocument( dirName varchar2, fileName varchar2 ) is
filehandle BFILE;
buffer CLOB;
warning varchar2(4000);
srcOffset integer := 1;
dstOffset integer := 1;
langContext integer := 0;
charSetID integer := 0;
procedure CleanupLoadDoc is
begin
-- discard the temporary CLOB
DBMS_LOB.FreeTemporary( buffer );
-- close open file
if DBMS_LOB.IsOpen( filehandle ) = 1 then
DBMS_LOB.FileClose( filehandle );
end if;
end;
begin
-- assign the filehandle
filehandle := BFilename( dirName, cFileName );
-- create a temporary CLOB
DBMS_LOB.CreateTemporary( buffer, FALSE );
-- read the contents of the file into a CLOB
DBMS_LOB.FileOpen( filehandle, DBMS_LOB.FILE_READONLY );
DBMS_LOB.LoadCLOBFromFile(
buffer, filehandle, DBMS_LOB.LOBMAXSIZE,
dstOffset, srcOffset, charSetID, langContext,
warning
-- save the contents
insert
into docs
values(
dirName,
fileName,
warning,
buffer
commit;
-- cleanup
CleanupLoadDoc;
exception when OTHERS then
-- as we cannot create resource protection blocks in PL/SQL,
-- we need to make sure we cleanup for both normal termination
-- and exceptions
CleanupLoadDoc;
raise;
end;
Once loaded a CLOB, the raw XML can be parsed using the XMTYPE function.
Oracle also has a component called XDB. This allows XSD's to be loaded, tables to be auto generated for the complex types in the XSD, loading XMLs into these tables, verifying that a XML complies with a XSD, etc.
But no easy examples at hand for these - suggest you read the Oracle XDB manual from start to end. (All Oracle docs for versions 8i to 11g available via http://tahiti.oracle.com)