java-client: which filterfields can be used when fetching da

Posted by agent_008_nl on 22-Feb-2012 06:56


OE11 serverside, java clients using java-proxies, and a progress CHUI client. I would like to provide the java-client (and the CHUI client) with info about which filter-fields can be used before a fetch-action is done. These filter-fields should result in picking up the right indexes in tables in the database. Maybe an xsd with index-info could be used.  For a prodataset you can 'import' an xsd using the read-xmlschema method. Is there something like read-xmlschema for the prodatagraph/ProDataGraphMetaData object or have you developed something for that and want to share? Or do you have another/better idea to provide clients with this info?

Regards, Stefan.

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Posted by Admin on 22-Feb-2012 07:38

Why do you need dynamic schema there?

And even if you need this to be dynamic I guess the schema (and probably  data as well) is generated by the ABL back-end and seems like it is a  dataset in the first place... why don't you simply use datase-handle  output parameter to pass that to both CHUI ABL client and Java?

Posted by agent_008_nl on 22-Feb-2012 07:59

Hi Marian,

I'm a java-dummy, the java-client is programmed by someone else in the team. Again another here suggested to do it what I tried to explain with an xsd, if it can be done in a more simple way I would be glad to hear. Maybe I have to explain a bit more: in my java-client I select the maintain orders screen. No data are presented yet, but I want the right filterfields to be shown above the empty grid(s). I only want filters that are supported by indexes. Do you propose to do an appservercall to get this index-info to build the client-screen?

Regrds, Stefan.

Posted by Admin on 23-Feb-2012 02:12

Stefan,  I guess the only place that can give you that kind of information is  the back-end so it has to be some sort of appserver call to get that or  might follow the ORM path and 'export' the database schema in a way your  client can make use of... reduce the number of appserver calls but need  to keep the schema information in sync.

Either  way you can pass that data as a dataset or XML, for ABL CHUI client  probably a dataset is the best thing but for Java client you'll have to  turn that info in some sort of an object... jaxb was mentioned on peg, I  use simplexml for that (because it's simple right).

Although  what are you trying to do might look legitimate from the database  developer perspective might not be what the user want and need... and  sometimes, if not always, the users knows better since they are using  the damn thing, we just have to catch-up with them and learn how they  actually use the application and improve the performance when needed  instead of restricting functionality

Nevertheless, as a theoretical discussion... what fields will you  consider as valid for filter operations? In an OLTP, especially  Progress, the indexes tend to be most of the time composed indexes, with  highly repetitive occurrence of 'primary key' fields in many of them  with added extra fields. You consider valid all fields that are part of a  index, only the first entry in the index, think any of the two options  could lead you to where you think you want to go?

Posted by agent_008_nl on 23-Feb-2012 03:56

Thanks Marian,

Good points, we will discuss them. If something interesting comes out I'll post it.

Kind regards, Stefan.

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