How to use FDS with Oracle DB?? JavaAdapter?

[kedward]

Hello,



Can anyone explain to me in plain english how my Flex
application uses FDS to connect to an oracle database?



Ok, so the mxml/swf calls the dataservice.... WHERE is the
dataservice? WHAT is the dataservice (functionaly a servlet?)?? HOW
is the dataservice configured?? Do I use J2ee connection pools?



Where are the detailed instructions for connecting my FDS
flex application to a backend oracle database?!?!?!



Ed

[kedward]

Hello,



OK, from reading the HORRIBLE adobe doc's on data services, I
am thinking that I just need to alter the below files.... but it
still doesn't work. I get a "No destination 'Employee' exists in
service flex.data.DataService" error when running the
application...... what am I missing?????:



1. add call to dataservice in the mxml file:



<"mx:Application xmlns:mx="
http://www.adobe.com/2006/mxml"
creationComplete="onCreationComplete()">

<mx:DataService id="ds" destination="Employee"
conflict="logEvent(event)" fault="logEvent(event)"
message="logEvent(event)"/>

<mx:VDividedBox width="800" height="100%">

<mx:Panel title="Employee::getEmployees()" width="800"



2. alter the data-management-config.xml to map the data
service id to the java class file



<destination id="Employee">

<adapter ref="java-dao"/>

<properties>

<source>com.theriabook.datasource.EmployeeAssembler</source>

<scope>application</scope>





3. The com.theriabook.datasource.EmployeeAssembler java class
abstracts the EmployeeDataServiceDAO class which contains the call
to the j2ee connection pool:



conn = JDBCConnection.getConnection("jdbc/theriabook");

if( logger.isDebugEnabled() ) logger.debug(" SQL: "+sql);

stmt = conn.prepareStatement(sql);

[seth_hodgson]

Hi Ed,



FDS is a Java web app that you can think of as having 3
layers:

1. A set of endpoints that clients connect to in order to
send and recieve data and messages. The HTTP and AMF endpoints are
implemented as a servlet. The RTMP endpoint is an NIO socket
server.

2. A core message broker that takes inbound messages and
routes them to their target service destination and routes
responses back out to connected clients.

3. A service layer with destinations that process these
messages from clients and if necessary return a response. Each
service exposes specific destinations. In the case of the remoting
service each destination is a Java object exposes for RPC, in
messaging each destination is a topic to publish to or subscribe
to, in the data service each destination is backed by an assembler
that manages a specific entity type in your domain model, etc.



In the data service case you can connect to a database either
via the HibernateAssembler or a custom assembler within which you
could talk to a DAO layer or manage CRUD ops directly. Your
assembler receives change objects for creates, updates, deletes and
the way you access your datastore is up to you. The intent of the
data service is to act as a layer on top of an existing Java domain
model on the server that allows Flash clients to interact with it
directly.



Hopefully that clarrifies the general picture a bit.



Regarding the error you're hitting, if that's a runtime error
being thrown on the client it's because the configuration
information compiled into the swf doesn't contain the "Employee"
destination you've added. How are you compiling your MXML app? If
you're compiling in FlexBuilder or at the command line are you
referencing your services-config.xml file using the -services
option?



Best,

Seth

[kedward]

Thanks,



What do you mean the configuration information is compilied
into the swf? I thought the whole purpose of the config file was
that it was kept outside the swf in the data-management-config.xml
?



Ed

[seth_hodgson]

The configuration files are used for two purposes.



1. To configure the server portion of FDS

2. A subset of the configuration data is injected into
compiled swfs to allow you to reach destinations on the server over
their supported channels/endpoints.



Taking your example: <mx:DataService id="ds"
destination="Employee" ...

Without injecting some of the configuration info into the
swf, there's no way for the DataService component to know how or
where to reach the "Employee" destination.



So you need to compile your swf using the -services compiler
option: -services=<path to your services-config.xml file>



Seth