Document Previewer error: ORA-00932: inconsistent datatypes: expected - got CLOB

Before the question starts, I have already posted this question in the Forge Discussion since this question is related to the Forge Module "Web Previewer" which allows people to have a pop-up screen to view a document (PDF strictly in my case). I checked the error log and found the error message which seems to be general, and I couldn't receive any answer for my question so I wonder you fellows may be able to help me. If this problem doesn't find an answer, I will also be very grateful if you can provide me a workaround or other way to achieve previewing documents.


I have this WebBlock inside a Webscreen where shows a table of files records that people uploaded, the records are saved in a List of file structure in a local variable.

I put the Web Previewer in such WebBlock, when people click on the name of the record, it execute the following OnClick action just like what it shows in the sample.

I did a debugging and when it reaches the Ajax refresh it has been all fine. But once I clicked the next step, the process stopped and at the browser it pops "Error executing query" as a red alert. However the whole process doesn't seem to do any DB query so I have completely no idea why this is happening.

I am using O11.



I checked the Service Center and it says tells the following error:

ORA-00932: inconsistent datatypes: expected - got CLOB

and I searched a bit and someone said that it might be because of the 2000 characters problem from the following URL:

https://www.outsystems.com/forums/discussion/32915/ora-00923-incosistent-datatypes-got-clob/

But I thought it was a binary? Please enlighten me.

Hi Stephen,

I'm not sure where the error comes from, or why it appears at that moment. However, you really shouldn't load all the binaries in the AttachmentList like you did, as it means all of them (and they're probably large) are kept in memory. It's better to just have the Id in the list, and query for the attachment data in the OnClickFileName Screen Action using the Id.

Secondly, did you check Service Center to see where exactly the error orginates? Especially check the stack trace, as it will show you the calling chain, which may help you see where the problem lies.

Kilian Hekhuis wrote:

Hi Stephen,

I'm not sure where the error comes from, or why it appears at that moment. However, you really shouldn't load all the binaries in the AttachmentList like you did, as it means all of them (and they're probably large) are kept in memory. It's better to just have the Id in the list, and query for the attachment data in the OnClickFileName Screen Action using the Id.

Secondly, did you check Service Center to see where exactly the error orginates? Especially check the stack trace, as it will show you the calling chain, which may help you see where the problem lies.

Sorry for the late response as I was working on other parts of the module. I also tried to use such forge module built-in sample and check the error message is also the same throwing about the data type CLOB. I am unsure about the reason.

What I did there was following the sample too.

Would anyone be able to replicate a successful case of using such module?