internal override void PropagateDataTypesForInSchema()
{
// Input for JOIN is the combination of both sources
var prevLeftSchema = InOperatorLeft.OutputSchema;
var prevRightSchema = InOperatorRight.OutputSchema;
var prevOutFields = prevLeftSchema.Union(prevRightSchema);
var fieldMapping = new Dictionary <Field, Field>();
foreach (var inF in InputSchema)
{
var matchOutFields = prevOutFields.Where(f => f.FieldAlias == inF.FieldAlias);
if (matchOutFields.Count() > 1)
{
// In case of join by node ids between left and right input (such as in MATCH .. OPTIONAL MATCH ... WHERE case)
// we will take the from left side and ignore duplications
// otherwise throws exception
if (!JoinPairs.All(jp => jp.Type == JoinKeyPair.JoinKeyPairType.NodeId))
{
throw new TranspilerInternalErrorException($"Ambiguous match of field with alias '{inF.FieldAlias}'");
}
}
if (matchOutFields.Count() == 0)
{
throw new TranspilerInternalErrorException($"Failed to match field with alias '{inF.FieldAlias}'");
}
fieldMapping.Add(inF, matchOutFields.First());
}
CopyFieldInfoHelper(InputSchema, fieldMapping.Values);
// additional validation on if relationships can satisfy the joins if directional traversal is explicitly specified
foreach (var joinPair in JoinPairs)
{
var nodeEntity = InputSchema.First(s => s.FieldAlias == joinPair.NodeAlias) as EntityField;
var relEntity = InputSchema.First(s => s.FieldAlias == joinPair.RelationshipOrNodeAlias) as EntityField;
switch (joinPair.Type)
{
case JoinKeyPair.JoinKeyPairType.Source:
if (relEntity.BoundSourceEntityName != nodeEntity.BoundEntityName)
{
throw new TranspilerBindingException($"Cannot find relationship ({nodeEntity.BoundEntityName})-[{relEntity.BoundSourceEntityName}]->(*), for {joinPair.NodeAlias} and {joinPair.RelationshipOrNodeAlias}");
}
break;
case JoinKeyPair.JoinKeyPairType.Sink:
if (relEntity.BoundSinkEntityName != nodeEntity.BoundEntityName)
{
throw new TranspilerBindingException($"Cannot find relationship ({nodeEntity.BoundEntityName})<-[{relEntity.BoundSourceEntityName}]-(*), for {joinPair.NodeAlias} and {joinPair.RelationshipOrNodeAlias}");
}
break;
default:
// in .Either, or .Both case
// no validation need to be done as Binding should already enforce the existence of the relationships
break;
}
}
}
internal override void PropagateDateTypesForOutSchema()
{
// projection may alter the schema with calculated columns
// we calculate the data type of all the fields in the output schema
// using type evaluation method on the QueryExpression
// Map from out_alias to { projection_expression,
// e.g.: (a.b + c) AS d
// "d" -> (<expression of a.b+c>, <d's field in OutputSchema>)
var exprToOutputMap = ProjectionMap.ToDictionary(
kv => kv.Key, // key is output alias
kv => new { Expr = kv.Value, Field = OutputSchema.First(f => f.FieldAlias == kv.Key) } // value is the corresponding field object and expression
);
foreach (var map in exprToOutputMap)
{
// toggle the fact if any of the output column requires aggregation
HasAggregationField = HasAggregationField ||
(map.Value.Expr.GetChildrenQueryExpressionType <QueryExpressionAggregationFunction>().Count() > 0);
var allPropertyReferences = map.Value.Expr.GetChildrenQueryExpressionType <QueryExpressionProperty>();
// update types for all QueryExpressionPropty object first based on InputSchema (so QueryExpression.EvaluteType() will work)
foreach (var prop in allPropertyReferences)
{
UpdatePropertyBasedOnAliasFromInputSchema(prop);
}
// then, update the type in the OutputSchema
if (map.Value.Field is EntityField)
{
// This can only be direct exposure of entity (as opposed to deference of a particular property)
// We just copy of the fields that the entity can potentially be dereferenced
Debug.Assert(allPropertyReferences.Count() == 1);
var varName = allPropertyReferences.First().VariableName;
var matchInputField = InputSchema.First(f => f.FieldAlias == varName);
map.Value.Field.Copy(matchInputField);
}
else
{
// This can be a complex expression involve multiple field/column references
// We will compute the type of the expression
Debug.Assert(map.Value.Field is ValueField);
var evalutedType = map.Value.Expr.EvaluateType();
var outField = map.Value.Field as ValueField;
outField.FieldType = evalutedType;
}
}
}
internal override void PropagateDateTypesForOutSchema()
{
// projection may alter the schema with calculated columns
// we calculate the data type of all the fields in the output schema
// using type evaluation method on the QueryExpression
var exprToOutputMap = ProjectionMap.ToDictionary(
kv => kv.Key, // key is output alias
kv => new { Expr = kv.Value, Field = OutputSchema.First(f => f.FieldAlias == kv.Key) } // value is the corresponding field object and expression
);
foreach (var map in exprToOutputMap)
{
// toggle the fact if any of the output column requires aggregation
HasAggregationField = HasAggregationField ||
(map.Value.Expr.GetChildrenQueryExpressionType <QueryExpressionAggregationFunction>().Count() > 0);
var allPropertyReferences = map.Value.Expr.GetChildrenQueryExpressionType <QueryExpressionProperty>();
if (map.Value.Field is EntityField)
{
// This can only be direct exposure of entity (as opposed to deference of a particular property)
// We just copy of the fields that the entity can potentially be dereferenced
Debug.Assert(allPropertyReferences.Count() == 1);
var varName = allPropertyReferences.First().VariableName;
var matchInputField = InputSchema.First(f => f.FieldAlias == varName);
map.Value.Field.Copy(matchInputField);
}
else
{
// This can be a complex expression involve multiple field/column references
// We will compute the type of the expression
Debug.Assert(map.Value.Field is ValueField);
// first of all, bind the type to the variable references
foreach (var prop in allPropertyReferences)
{
var varName = prop.VariableName;
var propName = prop.PropertyName;
Debug.Assert(prop.VariableName != null);
var matchedField = InputSchema.FirstOrDefault(f => f.FieldAlias == varName);
if (matchedField == null)
{
throw new TranspilerBindingException($"Failed to find input matching field alias {varName}");
}
if (string.IsNullOrEmpty(propName))
{
// direct reference to an alias (value column or entity column)
if (matchedField is ValueField)
{
prop.DataType = (matchedField as ValueField).FieldType;
}
else
{
// entity field reference in a single field expression
// this is valid only in handful situations, such as Count(d), Count(distinct(d))
// in such case, we populate the Entity object with correct entity type so that code generator can use it later
Debug.Assert(matchedField is EntityField);
var matchedEntity = matchedField as EntityField;
prop.Entity = matchedEntity.Type == EntityField.EntityType.Node ?
new NodeEntity()
{
EntityName = matchedEntity.EntityName, Alias = matchedEntity.FieldAlias
} as Entity:
new RelationshipEntity()
{
EntityName = matchedEntity.EntityName, Alias = matchedEntity.FieldAlias
} as Entity;
}
}
else
{
// property dereference of an entity column
if (!(matchedField is EntityField))
{
throw new TranspilerBindingException($"Failed to dereference property {propName} for alias {varName}, which is not an alias of entity type as expected");
}
var entField = matchedField as EntityField;
var entPropField = entField.EncapsulatedFields.FirstOrDefault(f => f.FieldAlias == propName);
if (entPropField == null)
{
throw new TranspilerBindingException($"Failed to dereference property {propName} for alias {varName}, Entity type {entField.BoundEntityName} does not have a property named {propName}");
}
entField.AddReferenceFieldName(propName);
prop.DataType = entPropField.FieldType;
}
}
// do data type evaluation
var evalutedType = map.Value.Expr.EvaluateType();
var outField = map.Value.Field as ValueField;
outField.FieldType = evalutedType;
}
}
}
