/// <summary>
/// Creates a column map for the given reader and function mapping.
/// </summary>
internal static CollectionColumnMap CreateFunctionImportStructuralTypeColumnMap(
DbDataReader storeDataReader, FunctionImportMappingNonComposable mapping, int resultSetIndex, EntitySet entitySet,
StructuralType baseStructuralType)
{
var resultMapping = mapping.GetResultMapping(resultSetIndex);
Debug.Assert(resultMapping != null);
if (resultMapping.NormalizedEntityTypeMappings.Count == 0) // no explicit mapping; use default non-polymorphic reader
{
// if there is no mapping, create default mapping to root entity type or complex type
Debug.Assert(!baseStructuralType.Abstract, "mapping loader must verify abstract types have explicit mapping");
return CreateColumnMapFromReaderAndType(
storeDataReader, baseStructuralType, entitySet, resultMapping.ReturnTypeColumnsRenameMapping);
}
// the section below deals with the polymorphic entity type mapping for return type
var baseEntityType = baseStructuralType as EntityType;
Debug.Assert(null != baseEntityType, "We should have entity type here");
// Generate column maps for all discriminators
var discriminatorColumns = CreateDiscriminatorColumnMaps(storeDataReader, mapping, resultSetIndex);
// Generate default maps for all mapped entity types
var mappedEntityTypes = new HashSet<EntityType>(resultMapping.MappedEntityTypes);
mappedEntityTypes.Add(baseEntityType); // make sure the base type is represented
var typeChoices = new Dictionary<EntityType, TypedColumnMap>(mappedEntityTypes.Count);
ColumnMap[] baseTypeColumnMaps = null;
foreach (var entityType in mappedEntityTypes)
{
var propertyColumnMaps = GetColumnMapsForType(storeDataReader, entityType, resultMapping.ReturnTypeColumnsRenameMapping);
var entityColumnMap = CreateEntityTypeElementColumnMap(
storeDataReader, entityType, entitySet, propertyColumnMaps, resultMapping.ReturnTypeColumnsRenameMapping);
if (!entityType.Abstract)
{
typeChoices.Add(entityType, entityColumnMap);
}
if (entityType == baseStructuralType)
{
baseTypeColumnMaps = propertyColumnMaps;
}
}
// NOTE: We don't have a null sentinel here, because the stored proc won't
// return one anyway; we'll just presume the data's always there.
var polymorphicMap = new MultipleDiscriminatorPolymorphicColumnMap(
TypeUsage.Create(baseStructuralType), baseStructuralType.Name, baseTypeColumnMaps, discriminatorColumns, typeChoices,
(object[] discriminatorValues) => mapping.Discriminate(discriminatorValues, resultSetIndex));
CollectionColumnMap collection = new SimpleCollectionColumnMap(
baseStructuralType.GetCollectionType().TypeUsage, baseStructuralType.Name, polymorphicMap, null, null);
return collection;
}
internal FunctionColumnMapGenerator(FunctionImportMappingNonComposable mapping, int resultSetIndex, EntitySet entitySet, StructuralType baseStructuralType)
{
_mapping = mapping;
_entitySet = entitySet;
_baseStructuralType = baseStructuralType;
_resultSetIndex = resultSetIndex;
}
/// <summary>
/// Determines the store type for a function import.
/// </summary>
private TypeUsage DetermineStoreResultType(MetadataWorkspace workspace, FunctionImportMappingNonComposable mapping, int resultSetIndex, out IColumnMapGenerator columnMapGenerator) {
// Determine column maps and infer result types for the mapped function. There are four varieties:
// Collection(Entity)
// Collection(PrimitiveType)
// Collection(ComplexType)
// No result type
TypeUsage storeResultType;
{
StructuralType baseStructuralType;
EdmFunction functionImport = mapping.FunctionImport;
// Collection(Entity) or Collection(ComplexType)
if (MetadataHelper.TryGetFunctionImportReturnType<StructuralType>(functionImport, resultSetIndex, out baseStructuralType))
{
ValidateEdmResultType(baseStructuralType, functionImport);
//Note: Defensive check for historic reasons, we expect functionImport.EntitySets.Count > resultSetIndex
EntitySet entitySet = functionImport.EntitySets.Count > resultSetIndex ? functionImport.EntitySets[resultSetIndex] : null;
columnMapGenerator = new FunctionColumnMapGenerator(mapping, resultSetIndex, entitySet, baseStructuralType);
// We don't actually know the return type for the stored procedure, but we can infer
// one based on the mapping (i.e.: a column for every property of the mapped types
// and for all discriminator columns)
storeResultType = mapping.GetExpectedTargetResultType(workspace, resultSetIndex);
}
// Collection(PrimitiveType)
else
{
FunctionParameter returnParameter = MetadataHelper.GetReturnParameter(functionImport, resultSetIndex);
if (returnParameter != null && returnParameter.TypeUsage != null)
{
// Get metadata description of the return type
storeResultType = returnParameter.TypeUsage;
Debug.Assert(storeResultType.EdmType.BuiltInTypeKind == BuiltInTypeKind.CollectionType, "FunctionImport currently supports only collection result type");
TypeUsage elementType = ((CollectionType)storeResultType.EdmType).TypeUsage;
Debug.Assert(Helper.IsScalarType(elementType.EdmType)
, "FunctionImport supports only Collection(Entity), Collection(Enum) and Collection(Primitive)");
// Build collection column map where the first column of the store result is assumed
// to contain the primitive type values.
ScalarColumnMap scalarColumnMap = new ScalarColumnMap(elementType, string.Empty, 0, 0);
SimpleCollectionColumnMap collectionColumnMap = new SimpleCollectionColumnMap(storeResultType,
string.Empty, scalarColumnMap, null, null);
columnMapGenerator = new ConstantColumnMapGenerator(collectionColumnMap, 1);
}
// No result type
else
{
storeResultType = null;
columnMapGenerator = new ConstantColumnMapGenerator(null, 0);
}
}
}
return storeResultType;
}
private static ScalarColumnMap[] CreateDiscriminatorColumnMaps(DbDataReader storeDataReader, FunctionImportMappingNonComposable mapping, int resultIndex)
{
// choose an arbitrary type for discriminator columns -- the type is not
// actually statically known
EdmType discriminatorType =
MetadataItem.EdmProviderManifest.GetPrimitiveType(PrimitiveTypeKind.String);
TypeUsage discriminatorTypeUsage =
TypeUsage.Create(discriminatorType);
IList<string> discriminatorColumnNames = mapping.GetDiscriminatorColumns(resultIndex);
ScalarColumnMap[] discriminatorColumns = new ScalarColumnMap[discriminatorColumnNames.Count];
for (int i = 0; i < discriminatorColumns.Length; i++)
{
string columnName = discriminatorColumnNames[i];
ScalarColumnMap columnMap = new ScalarColumnMap(discriminatorTypeUsage, columnName, 0,
GetDiscriminatorOrdinalFromReader(storeDataReader, columnName, mapping.FunctionImport));
discriminatorColumns[i] = columnMap;
}
return discriminatorColumns;
}
