Native XML Database or RDBMS

1
Native XML Database or RDBMS
2
Data or Document orientation

• If you are primarily storing documents, then a
  Native XML Database may be the best option.
  However it will depend on document structure and
  on the kinds of questions you need to ask about
  the information / data that the documents
  contain.

3
Native XML Database

• If primarily storing and querying the content of
  documents, especially with
• varying structure.
• mixed content
• recursive content
• complex mix of elements and attributes
• Documents best encoded handled with XML
• If you have lots of different XML datatypes and
  schema or you have lots of well-formed XML to
  deal with, the native XML DBMSs make it much
  easier to efficiently store and retrieve
  well-formed XML.

4
RDBMS

• If you are primarily storing data or
  data-oriented documents (primarily of interest to
  an application) then mapping documents into
  relations may be appropriate where there is
• clear metadata
• head-body structure primarily queried on metadata
  (which tends to be fixed structure)
• a simple schema - otherwise you get
• lots of tables, complex query joins and slow
  access times
• few tables and lots of null column entries which
  need complex interpretation
• If you have a small number of XML schema to work
  with, are able and prepared to design appropriate
  storage strategies and to build data loading
  programs, an XML-enabled RDBMS may be
  satisfactory.

5

• Importing and Exporting XML to/from MSAccess
• http//msdn.microsoft.com/library/default.asp?url
  /library/en-us/dnacc2k2/html/odc_accessxml.asp
• Oracle9i SQL/XML
• http//www.oracle.com/technology/oramag/oracle/03-
  may/o33xml.html
• Native XQuery engine integrated with Oracle
  Database 10g Release 2.
• http//www.oracle.com/technology/pub/articles/vasi
  liev_xquery.html

6
Complexity of queries

• The ways in which information will be queried is
  an important factor.
• Retrieval / manipulation of structured data --
  RDBMS
• Full-text searching, or manipulating a recursive
  content model --Native XML Database or XML
  enabled Database with an appropriate XML query
  language
• e.g. bill of materials or build configuration
  queries are difficult for SQL, but
  straightforward in XPath

7
Existing investment

• DBMS
• Existing applications and data resources
• Tools and add-ons
• report generators
• forms
• Skill-sets
• 3NF
• SQL
• Experience of existing environment

8
Relative Cost

• If you have a heavy investment in an
  Object-Relational DBMS their XML add-on support
  may be appropriate. If you are starting from
  scratch, the Native XML DBMSs are generally
  cheaper, lighter, and easier to manage.

9
Data integrity

• Referential integrity is at the core of the
  relational model.
• In XML the concept of integrity is less well
  defined and application code will be required to
  maintain integrity.
• If there is a strong requirement for data
  integrity, then a relational or XML enabled
  database may be the better solution.
• When mapping an XML document into a relational
  database (if you're not using a BLOB to store the
  whole document), some information about the
  document will be lost. If you require that data
  must retain its original structure, into and out
  of storage, then an Native XML Database is the
  best solution.