markap14 commented on a change in pull request #4282:
URL: https://github.com/apache/nifi/pull/4282#discussion_r427525012
##########
File path:
nifi-nar-bundles/nifi-standard-bundle/nifi-standard-processors/src/main/java/org/apache/nifi/queryrecord/FlowFileTable.java
##########
@@ -223,12 +225,69 @@ private RelDataType getRelDataType(final DataType
fieldType, final JavaTypeFacto
case BIGINT:
return typeFactory.createJavaType(BigInteger.class);
case CHOICE:
+ final ChoiceDataType choiceDataType = (ChoiceDataType)
fieldType;
+ DataType widestDataType =
choiceDataType.getPossibleSubTypes().get(0);
+ for (final DataType possibleType :
choiceDataType.getPossibleSubTypes()) {
+ if (possibleType == widestDataType) {
+ continue;
+ }
+ if
(possibleType.getFieldType().isWiderThan(widestDataType.getFieldType())) {
+ widestDataType = possibleType;
+ continue;
+ }
+ if
(widestDataType.getFieldType().isWiderThan(possibleType.getFieldType())) {
+ continue;
+ }
+
+ // Neither is wider than the other.
+ widestDataType = null;
+ break;
+ }
+
+ // If one of the CHOICE data types is the widest, use it.
+ if (widestDataType != null) {
+ return getRelDataType(widestDataType, typeFactory);
+ }
+
+ // None of the data types is strictly the widest. Check if all
data types are numeric.
+ // This would happen, for instance, if the data type is a
choice between float and integer.
+ // If that is the case, we can use a String type for the table
schema because all values will fit
+ // into a String. This will still allow for casting, etc. if
the query requires it.
+ boolean allNumeric = true;
+ for (final DataType possibleType :
choiceDataType.getPossibleSubTypes()) {
+ if (!isNumeric(possibleType)) {
+ allNumeric = false;
+ break;
+ }
+ }
+
+ if (allNumeric) {
Review comment:
As an example, consider a csv like:
```
name, other
markap14, 48
pcgrenier, computer
```
In this case, the schema has a field with name 'name' and a type String. But
'other' field is a CHOICE[INT, STRING]. So what should best represent that
field in terms of java objects? I'd say `Object.class`. The `String.class`
being used here is honestly a bit of a hack because Calcite doesn't give us a
better way to represent Number - or, at least, not to my knowledge :)
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