[CALCITE-1551] fix for: RelBuilder's project() doesn't preserve alias #340
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This is accomplished by changing the structure of the Frame in RelBuilder to include alias and field information for all fields in the relnode irrespective of their origin. Rel aliases also preserved on group keys through aggregate operations.
aggregate aliases
julianhyde
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ldming
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This is accomplished by changing the structure of the Frame in RelBuilder to include alias and field information for all fields in the RelNode irrespective of their origin. Rel aliases also preserved on group keys through aggregate operations. In PigRelBuilder, we retain aggregate aliases, because Pig Latin relies upon them. Close apache/calcite#340
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This is accomplished by changing the structure of the Frame in
RelBuilder to include alias and field information for all fields in the
relnode irrespective of their origin. Rel aliases also preserved on
group keys through aggregate operations.
General approach:
Framenow maintains a list of fields, each field having a set of rel aliases by which it can be referred to. I renamedFrame.righttoFrame.fieldsand the type is nowPair<Set<String>, RelDataTypeField>.RelBuilder.field(alias, fieldName)modified slightly to check aliases and field name equality. Code is simpler now as there is an entry for each field.RelBuilder.project()modified to build a field list preserving any aliases linked byRexInputRefnodes.RelBuilder.filter(), sort, sortLimit modified to retain the existing set of aliases & fields.RelBuilder.aggregate()modified to retain aliases of group keys which areRexInputRefnodes.A few notes about the patch:
PigRelBuilderto use anullalias for theaggregateCall(). It was previously taken from the (first) rel alias which doesn't seem to have any utility. If this needs to do something else, I'll gladly change it.RelBuilder.field(ordinals)uses a special version offield()which may assign an alias. I didn't understand the original intention of this in 2193c6e. I'm no longer using thataliasargument and everything seems to work well without it. Is it ok to remove?