Question: Oracle is offering more than
one possibility to save XML into its DB. Can you explain the different
ways that you can store an XML document in Oracle?
Answer: Oracle has several procedures and techniques for inserting
data, either in-line (inside the tablespace) or offline using the BFILE syntax.
Begin
DBMS_XMLSCHEMA.registerSchema(
schemaURL => 'Mailpiece_Processing/oif_dtypes',
schemaDoc => bfilename('XML_TEST','oif_dtypes.xsd'));
End;
Create table XML_default auf XMLType
insert into xml_default
values
(
XMLTYPE
(
Bfilename ('XML_TEST', 'Test.xml'),
nls_charset_id('AL32UTF8'
));
Also, note that the best benefit of XML-DB
is the ability to validate document structure with DTD's, which Oracle has
re-named XSD's (XML-DB
schema definition):
Rampant author V. J. Jain has a
good
article on storing XML inside Oracle with XSD definitions.
Question: If I import XML with
the BFILE option, is it called CLOB Storage or object relational?
Answer: I would say "both"! The main difference between
relational and object-relational is the use of pointers (file location address),
so the BFILE function is indeed object-oriented. It's also properly called CLOB
storage, but remember that CLOB's can also be stored in the tablespace without
pointers.
Using the BFILE construct is outside Oracle, and all Oracles does is maintain a
"pointer" to the file location where the CLOB resides. Oracle DOES not manage
the data itself, in a traditional relational sense.
So, does this non-relational storage make it "object relational"? I would say
"Yes".
In a true object-oriented database, the DBMS is nothing more that a persistence
method for allowing object permanence. It's more like a C++ language extension
than a DBMS.
What is "object oriented Oracle"? It's the incorporation of the OO constructs
such as polymorphism, encapsulation and inheritance, but it also include the
"create type" ability where you can define
non-traditional storage
constructs (nested tables, VARRAY columns, capturing OID's that point to
rows).
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