I just re-tested with simple source/view table transformation using "double" and "float" and my button is enabled.
Please log a JIRA and attach your source and view models (or an exported Model Project Set) so we can debug it.
Teiid Designer Project
We figured out we can have that button enabled now if we do mapping in another way.
Now the problem is, we picked the "convert" option for the virtual column, but we can't query against that column, we got this error:
14:18:55,546 WARN [org.teiid.PROCESSOR] (Worker4_QueryProcessorQueue39) TEIID30020 Processing exception 'TEIID30328 Unable to evaluate convert(Petrel_SM.PetrelMarker.DipAngle, float): TEIID30384 Error while evaluating function convert' for request jPSnK8VBPZty.6. Exception type org.teiid.api.exception.query.ExpressionEvaluationException thrown from org.teiid.core.types.Transform.checkValueRange(Transform.java:112). Enable more detailed logging to see the entire stacktrace.
BTW, the middle column "Matched Datatype", what is that for? How to pick the type for it?
For the exception, maybe check your datatype properties (precision, length, etc.) to make sure the number you are converting is compatible.
The Matched Datatype is what Designer discovers as the compatible runtime datatype based on the source column datatype
For the benefit of all, let me elaborate little on what jane_lj found.
Usual way of doing the mapping is select an apporpriate SQL symbol (i.e., source attribute) and select a virtual target column and use "< Bind" button to map them.
The convert of souce SQL Symbol to target datatype will be enabled in this scenario.
Though the resulting SQL will be same as in the previous case, the convert of souce SQL Symbol to target datatype will be disabled.
Thanks for your hint, the root cause is some bad data, nothing else was wrong.