CSHARP-1913: Support using Dictionary fields as IEnumerable<KeyValuePair<TKey, TValue>> #1800
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| public bool TryGetItemSerializationInfo(out BsonSerializationInfo serializationInfo) | ||
| { | ||
| if (_dictionaryRepresentation != DictionaryRepresentation.ArrayOfDocuments) | ||
| if (_dictionaryRepresentation is DictionaryRepresentation.ArrayOfArrays or DictionaryRepresentation.ArrayOfDocuments) |
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We were sort of working with ArrayOfDocuments representation, but this adds support for ArrayOfArrays.
| var ienumerableSerializer = ArraySerializerHelper.CreateSerializer(keyValuePairSerializer); | ||
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| return new TranslatedExpression(aggregateExpression.Expression, ast, enumerableSerializer); | ||
| aggregateExpression = new TranslatedExpression(expression, ast, ienumerableSerializer); |
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Both of the above cases share this in common: they are both cases where an enumerable value has the values represented in some unusual way other than as a BsonArray.
The first case corresponds to IGrouping<TKey, TElement> where the elements are wrapped one level deeper in an _elements field.
The second is new in this PR, and corresponds to a Dictionary<TKey, TValue> with the Document representation. In order to use this dictionary as an enumerable of KeyValuePair<TKey, TValue> we have to insert a call to $objectToArray.
| var selectorParameter = selectorLambda.Parameters.Single(); | ||
| var selectorParameterSymbol = context.CreateSymbol(selectorParameter, sourceSerializer, isCurrent: true); | ||
| var selectorContext = context.WithSymbol(selectorParameterSymbol); | ||
| var selectorTranslation = ExpressionToAggregationExpressionTranslator.TranslateEnumerable(selectorContext, selectorLambda.Body); |
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Need to call TranslateEnumerable instead of Translate.
rstam
changed the title
| AssertStages( | ||
| stages, | ||
| "{ $match : { Name : 'TestName' } }", | ||
| "{ $project : { _v : { $reduce : { input : { $map : { input : '$DictionaryWithArrayOfArraysRepresentation', as : 'kvp', in : ['$$kvp'] } }, initialValue : [], in : { $concatArrays : ['$$value', '$$this'] } } }, _id : 0 } }"); |
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I would have liked to use kvp.Key or kvp.Value in the test test but that is not (yet) supported when the KeyValuePair is represented as an array. So I just used the entire KeyValuePair.
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I have getting the Key or Value of a KeyValuePair represented as an array supported in my work for full support of dictionary representations. So I'll probably update this test when I rebase on this PR.
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As discussed in our meeting, we can remove this test.
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I think this test serves a useful purpose in proving that this PR also fixes 4251 but at your request I will remove it.
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remove extra spacing here.
| AssertStages( | ||
| stages, | ||
| "{ $match : { Name : 'TestName' } }", | ||
| "{ $project : { _v : { $reduce : { input : { $map : { input : '$DictionaryWithArrayOfArraysRepresentation', as : 'kvp', in : ['$$kvp'] } }, initialValue : [], in : { $concatArrays : ['$$value', '$$this'] } } }, _id : 0 } }"); |
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I have getting the Key or Value of a KeyValuePair represented as an array supported in my work for full support of dictionary representations. So I'll probably update this test when I rebase on this PR.
2 participants
SelectMany expects the selector to return an enumerable value.
Dictionary is a special case of an enumerable value, and we have to treat it specially.