Database Reference
In-Depth Information
elements represent data and attributes represent metadata,
though this is not part of any XML standard.
XML Schemas (and documents) may have more struc-
ture than the columns of a table. Groups, such as Phone and
Address, can be defined. An XML Schema that has all ele-
ments at the same level is a flat schema. Structured schemas
are those that have defined subgroups, such as Phone and
Address. To avoid definition duplication, elements can be
defined globally. Duplication is undesirable because there is
the risk that definitions will become inconsistent if a change
is made to one definition and not the other.
SQL Server, Oracle Database, and MySQL can produce
XML documents from database data. The Oracle Database
facilities require the use of Java; see
www.oracle.com
for
more information. SQL Server supports an add-on expres-
sion to the SQL SELECT statement, the FOR XML expres-
sion. FOR XML can be used to produce XML documents in
which all data are expressed as attributes or as elements.
FOR XML can also write an XML Schema description as
well as the XML document. Using FOR XML EXPLICIT, the
developer can place some columns into elements and oth-
ers into attributes.
When interpreting multitable selects, the FOR XML
processor uses the order of the tables to determine the hier-
archical order of elements in the document. FOR XML can
be used to produce XML documents with one multivalued
path. Documents with more than one multivalued path must
be patched together in the application by some means.
XML is important because it facilitates the sharing of
XML documents (and hence database data) among organi-
zations. After an XML Schema has been defined, organiza-
tions can ensure that they are receiving and sending only
schema-valid documents. Additionally, XSL documents can
be coded to transform any schema-valid XML document,
from any source, into other standardized formats. These
advantages become even more important as industry groups
standardize their own XML Schemas. XML also facilitates
business-to-business processing. This chapter concludes
with a brief description of additional XML standards: XPath,
SAX, DOM, XQuery, and XML Namespaces.
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.NET Framework
.NET for Windows Store Apps
abstraction
Active Data Objects (ADO)
Active Server Pages (ASP)
ADO.NET
ADO.NET Command object
ADO.NET Connection object
ADO.NET Data Provider
ADO.NET DataAdapter object
ADO.NET DataReader
ADO.NET DataSet
ADO.NET Entity Framework
AMP
Apache Tomcat
Apache Web server
applet
application program interface (API)
ASP.NET
Base Class Library
bytecode interpreter
Callable Statement object
collection
Common Language Runtime (CLT)
Component Object Model (COM)
Constraints
current values
cursor
data consumer
data provider
DataColumnsCollection
DataRelationCollection
DataRelations
DataRowCollection
DataTable object
DataTableCollection
Default Web Site folder
DeleteCommand object
document type declaration (DTD)
Eclipse IDE
Eclipse PDT (PHP Development Tools)
Project
Entity Data Model (EDM)
Extensible Markup Language (XML)
file data source
ForeignKeyConstraint
HTML document tags
HTML syntax rules
Hypertext Markup Language (HTML)
iisstart.htm
implementation
index.html
inetpub folder
InsertCommand object
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