Work in progress This version may be updated without notice.

1 The RDBMS module

This Active Tags module has been designed to provide basic RDBMS support.

1.1 Performing SQL queries

This module is somewhat very simple to use :

• create a connection to the database with <rdbms:connect>,
• submit a request with <rdbms:select> or <rdbms:update>,
• commit updates operations with <rdbms:commit>, or browse the result of the SELECT query like a adt:list.

SQL queries accept prepared SQL statements, which parameters are set with entries found in the context after performing the subactions.

    <rdbms:connect driver="com.mysql.jdbc.Driver" name="sql" password="{ $sys:env/password }"
 url="jdbc:mysql://localhost:3306/employees" user="{ $sys:env/user }"/>
    <rdbms:select connection="{ $sql }" name="result-set" query="SELECT EMPLOYEES WHERE ID = ?">
        <xcl:param value="{ $employee-id }"/>
    </rdbms:select>

    <rdbms:update connection="{ $sql }" name="result-count"
 query="UPDATE EMPLOYEES SET SALARY = ? WHERE ID = ?">
        <xcl:param value="{ $employee-salary }"/>
        <xcl:param value="{ $employee-id }"/>
    </rdbms:update>

1.2 Producing straightly the expected XML structure

Unlike any proprietary technique of database vendors, Active Tags allows to produce directly any XML structure without the help of XSLT. Active Tags offers very flexible means for designing arbitrary complex XML structures. Active Tags allows actually :

• to choose which results have to be an attribute, and which have to be an element,
• to name elements and attributes, even if a name is taken from the value of a column,
• to decide precisely how to nest elements, particularly when an element container is wanted,
• to perform operations and use functions other than those supplied by SQL,
• etc

    <rdbms:connect driver="..." name="sql" password="..." url="..." user="..."/>
    <rdbms:select connection="{ $sql }" name="orders" query="SELECT * FROM orders WHERE id= ? ">
        <xcl:param value="{ $sys:env/order-id }"/>
    </rdbms:select>
    <xcl:document name="xml">
        <order id="{ $sys:env/order-id }">
            <xcl:for-each name="group" select="{ xcl:group( $orders, currency ) }">
                <xcl:element name="{ currency }">
                    <xcl:for-each select="{ $group }">
                        <item part-number="{ pn }" quantity="{ qty }">
                            { price }
                            <xcl:text>{ string( product ) }</xcl:text>
                        </item>
                    </xcl:for-each>
                </xcl:element>
            </xcl:for-each>
        </order>
    </xcl:document>

<order id="1234">
    <dollar>
        <item part-number="321" price="138.95" quantity="1">Lawnmower</item>
        <item part-number="654" price="29.99" quantity="2">Baby Monitor</item>
    </dollar>
    <euro>
        <item part-number="987" price="11.27" quantity="3">Roquefort Cheese</item>
    </euro>
</order>

2 RDBMS module reference

	Must be an adt:expression that computes an object of the type expected.
	Must be a hard-coded value (litteral)
	Can be either a hard-coded value or an adt:expression
	This material may be missing
	Denotes a value to use by default
	Allows a read operation.
	Allows a write operation.
	Allows a rename operation.
	Allows an update operation.
	Allows a delete operation.

2.1 Elements

2.2 Foreign attributes

@rdbms:version

• Priority : 0

The version of the RDBMS module to use. This attribute should be encountered before any RDBMS element, but it takes precedence on the element inside which it is hosted.

2.3 Predefined properties

$rdbms:null

$rdbms refers to null values in the database.

2.4 Extended XPath functions

No XPath functions are defined by this module.

2.5 Data types

rdbms:connection type

Represents a connection to the data base.

rdbms:x-row type

Represents a row of a result set of a query.

Operation			read | write | rename | update | delete
	Type	Value	Comment
type()
	xs:QName	rdbms:x-row	This type
child::
	adt:list		Each item has a name and a value of the type supplied by the underlying implementation.

Appendix

A Glossary

B Related Active Tags specifications

This list is not exhaustive; it is a list of common modules usable by an engine that implements the Active Tags specifications that implementors may use. Additional modules are welcome.

C Lists

C.1 Examples list

• Performing a SELECT query
• Performing an UPDATE query
• SQL to XML

C.2 Figures list

D Active Schema for the RDBMS module

[schema.asl]

<asl:active-schema asl:version="1.0" adt:version="1.0" xs:version="1.0" target="web"
 schema-version="1.0" xml:lang="en"
    xmlns:rdbms="http://www.inria.fr/xml/active-tags/rdbms"
    xmlns:asl="http://www.inria.fr/xml/active-schema"
    xmlns:adt="http://www.inria.fr/xml/active-datatypes"
    xmlns:xs="http://www.w3.org/2001/XMLSchema-datatypes"
    xmlns="http://www.w3.org/1999/xhtml"
    xmlns:at="http://www.inria.fr/xml/active-tags/reference">

    <asl:element name="rdbms:select" root="never">
        <!-- TODO -->
    </asl:element>

    <!-- TODO -->

</asl:active-schema>