/// <summary>
/// Determines the expected shape of store results. We expect a column for every property
/// of the mapped type (or types) and a column for every discriminator column. We make no
/// assumptions about the order of columns: the provider is expected to determine appropriate
/// types by looking at the names of the result columns, not the order of columns, which is
/// different from the typical handling of row types in the EF.
/// </summary>
/// <remarks>
/// Requires that the given function import mapping refers to a Collection(Entity) or Collection(ComplexType) CSDL
/// function.
/// </remarks>
/// <returns>Row type.</returns>
internal TypeUsage GetExpectedTargetResultType(MetadataWorkspace workspace, int resultSetIndex)
{
FunctionImportStructuralTypeMappingKB resultMapping = this.GetResultMapping(resultSetIndex);
// Collect all columns as name-type pairs.
Dictionary <string, TypeUsage> columns = new Dictionary <string, TypeUsage>();
// Figure out which entity types we expect to yield from the function.
IEnumerable <StructuralType> structuralTypes;
if (0 == resultMapping.NormalizedEntityTypeMappings.Count)
{
// No explicit type mappings; just use the type specified in the ReturnType attribute on the function.
StructuralType structuralType;
MetadataHelper.TryGetFunctionImportReturnType <StructuralType>(this.FunctionImport, resultSetIndex, out structuralType);
Debug.Assert(null != structuralType, "this method must be called only for entity/complextype reader function imports");
structuralTypes = new StructuralType[] { structuralType };
}
else
{
// Types are explicitly mapped.
structuralTypes = resultMapping.MappedEntityTypes.Cast <StructuralType>();
}
// Gather columns corresponding to all properties.
foreach (StructuralType structuralType in structuralTypes)
{
foreach (EdmProperty property in TypeHelpers.GetAllStructuralMembers(structuralType))
{
// NOTE: if a complex type is encountered, the column map generator will
// throw. For now, we just let them through.
// We expect to see each property multiple times, so we use indexer rather than
// .Add.
columns[property.Name] = property.TypeUsage;
}
}
// Gather discriminator columns.
foreach (string discriminatorColumn in this.GetDiscriminatorColumns(resultSetIndex))
{
if (!columns.ContainsKey(discriminatorColumn))
{
//
TypeUsage type = TypeUsage.CreateStringTypeUsage(workspace.GetModelPrimitiveType(PrimitiveTypeKind.String), true, false);
columns.Add(discriminatorColumn, type);
}
}
// Expected type is a collection of rows
RowType rowType = new RowType(columns.Select(c => new EdmProperty(c.Key, c.Value)));
TypeUsage result = TypeUsage.Create(new CollectionType(TypeUsage.Create(rowType)));
return(result);
}
internal FunctionImportNormalizedEntityTypeMapping(FunctionImportStructuralTypeMappingKB parent,
List <FunctionImportEntityTypeMappingCondition> columnConditions, BitArray impliedEntityTypes)
{
// validate arguments
EntityUtil.CheckArgumentNull(parent, "parent");
EntityUtil.CheckArgumentNull(columnConditions, "discriminatorValues");
EntityUtil.CheckArgumentNull(impliedEntityTypes, "impliedEntityTypes");
Debug.Assert(columnConditions.Count == parent.DiscriminatorColumns.Count,
"discriminator values must be ordinally aligned with discriminator columns");
Debug.Assert(impliedEntityTypes.Count == parent.MappedEntityTypes.Count,
"implied entity types must be ordinally aligned with mapped entity types");
this.ColumnConditions = new OM.ReadOnlyCollection <FunctionImportEntityTypeMappingCondition>(columnConditions.ToList());
this.ImpliedEntityTypes = impliedEntityTypes;
this.ComplementImpliedEntityTypes = (new BitArray(this.ImpliedEntityTypes)).Not();
}
internal FunctionImportNormalizedEntityTypeMapping(
FunctionImportStructuralTypeMappingKB parent,
List<FunctionImportEntityTypeMappingCondition> columnConditions, BitArray impliedEntityTypes)
{
// validate arguments
//Contract.Requires(parent != null);
//Contract.Requires(columnConditions != null);
//Contract.Requires(impliedEntityTypes != null);
Debug.Assert(
columnConditions.Count == parent.DiscriminatorColumns.Count,
"discriminator values must be ordinally aligned with discriminator columns");
Debug.Assert(
impliedEntityTypes.Count == parent.MappedEntityTypes.Count,
"implied entity types must be ordinally aligned with mapped entity types");
ColumnConditions = new ReadOnlyCollection<FunctionImportEntityTypeMappingCondition>(columnConditions.ToList());
ImpliedEntityTypes = impliedEntityTypes;
ComplementImpliedEntityTypes = (new BitArray(ImpliedEntityTypes)).Not();
}
/// <summary>
/// Gets the disctriminator columns resultSetIndexth result set, or an empty array if the index is not in range
/// </summary>
internal IList <string> GetDiscriminatorColumns(int resultSetIndex)
{
FunctionImportStructuralTypeMappingKB resultMapping = this.GetResultMapping(resultSetIndex);
return(resultMapping.DiscriminatorColumns);
}
/// <summary>
/// Given discriminator values (ordinally aligned with DiscriminatorColumns), determines
/// the entity type to return. Throws a CommandExecutionException if the type is ambiguous.
/// </summary>
internal EntityType Discriminate(object[] discriminatorValues, int resultSetIndex)
{
FunctionImportStructuralTypeMappingKB resultMapping = this.GetResultMapping(resultSetIndex);
Debug.Assert(resultMapping != null);
// initialize matching types bit map
BitArray typeCandidates = new BitArray(resultMapping.MappedEntityTypes.Count, true);
foreach (var typeMapping in resultMapping.NormalizedEntityTypeMappings)
{
// check if this type mapping is matched
bool matches = true;
var columnConditions = typeMapping.ColumnConditions;
for (int i = 0; i < columnConditions.Count; i++)
{
if (null != columnConditions[i] && // this discriminator doesn't matter for the given condition
!columnConditions[i].ColumnValueMatchesCondition(discriminatorValues[i]))
{
matches = false;
break;
}
}
if (matches)
{
// if the type condition is met, narrow the set of type candidates
typeCandidates = typeCandidates.And(typeMapping.ImpliedEntityTypes);
}
else
{
// if the type condition fails, all implied types are eliminated
// (the type mapping fragment is a co-implication, so a type is no longer
// a candidate if any condition referring to it is false)
typeCandidates = typeCandidates.And(typeMapping.ComplementImpliedEntityTypes);
}
}
// find matching type condition
EntityType entityType = null;
for (int i = 0; i < typeCandidates.Length; i++)
{
if (typeCandidates[i])
{
if (null != entityType)
{
throw EntityUtil.CommandExecution(System.Data.Entity.Strings.ADP_InvalidDataReaderUnableToDetermineType);
}
entityType = resultMapping.MappedEntityTypes[i];
}
}
// if there is no match, raise an exception
if (null == entityType)
{
throw EntityUtil.CommandExecution(System.Data.Entity.Strings.ADP_InvalidDataReaderUnableToDetermineType);
}
return(entityType);
}
