Oracle Database Discussions

em.createNamedQuery("Memos.findPhoto", Memos.class)

em.createNamedQuery("Memos.getPhoto", Memos.class) 
mage/jpeg','image/jpeg',

Well, when you use some api, you first need to read (and understand ) docs for it.

Here is description for createNamedQuery() with two parameters(note that there is also the same method with only one parameter): https://docs.oracle.com/javaee/6/api/javax/persistence/EntityManager.html#createNamedQuery%28java.lang.String,%20java.la…

Dario

Hi Dario, thk for your reply but I'm not following.

What does the createNamedQuery as to do with it?

That part of code was generated when I added them to my SessionBean

That part of code was generated when I added them to my SessionBean

Are these queries also generated?

1. @NamedQuery(name = "Memos.findPhoto", query = "select o.thememo from Memos o where o.sourceid = :recid and o.memotyp = 101"), 
2. @NamedQuery(name = "Memos.getPhoto", query = "select 'image/jpeg', o.thememo from Memos o where o.sourceid = :recid and o.memotyp = 101") 

Like I said in previous reply, read docs for createNamedQuery(), then analyze your queries(hint: look at select clause) and you will find issue.

Dario

I get it Dario, I cannot add that 'image/jpeg', in the query, so both queries I have presented are wrong.

In this case I can only create a function that use a query to get the row where the image is and return that image.

Since I'm working with byte[], my service function will have to treat that data and convert it so it can be read as as image.

Am I correct, thinking this way?

So why you don't use createdNamedQuery() with only one parameter?

Something like this: http://stackoverflow.com/questions/5498391/how-to-download-a-file-stored-in-a-database-with-jsf-2-0

Dario

I can use it, but in my class that attribute is recognized as a byte[] and when I add that 'query' to my SessionBean it will create a function that returns a List<Byte>. I can't even return the array that getTheMemo will return.

This brings me another question, how can I define in the query, if possible, that the return of it is a class object or a type like string or something else?

I'm not sure that I understand your question.

You can define your own @NamedQuery then define your own java method to invoke that query and return byte[] or whatever you want.

(like downloadGarbage(Long id) function in referred stack overflow link)

Dario

What you are saying, if I understand it correctly is that I don't have to define the functions that call the queries through Session bean facade options.

I create those references by hand in the session bean and interface and it won't establish a 'direct' connection between them.

This way I can control everything.

Thanks Dario, it works.

When I was adding the service to my client, which was a little bit tricky, I encountered a post referring streamed and non-streamed.

byte[] imageData = SessionBean.getPhoto(recid);

// uncomment line below to send non-streamed
//return Response.ok(imageData).build();

// uncomment line below to send streamed
return Response.ok(new ByteArrayInputStream(imageData)).build();

I tried to find something that could explain the difference between them but i didn't quite understand.

Which one is better or in which situations?

Thanks

You already have complete content retrieved as byte array on the server so this is probably irrelevant.

Streaming is good if you have large file(because you will not load whole file to server memory) or for video streams(because there is no need to show all content at once).

If you want to effectively use streaming, you need to retrieve data from database as stream, and then pass this stream to http response.

Dario