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Refactor - break up fat method FindSchemaMappingFragment
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Names could still be clearer, it's all very abstract, but it's a start.
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@timabell
timabell committed Feb 21, 2015
1 parent 960570e commit 3e431a7
Showing 1 changed file with 103 additions and 69 deletions.
172 changes: 103 additions & 69 deletions EfEnumToLookup/LookupGenerator/MetadataHandler.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,12 @@

class MetadataHandler
{
// refs:
// * http://romiller.com/2014/04/08/ef6-1-mapping-between-types-tables/
// * http://blogs.msdn.com/b/appfabriccat/archive/2010/10/22/metadataworkspace-reference-in-wcf-services.aspx
// * http://msdn.microsoft.com/en-us/library/system.data.metadata.edm.dataspace.aspx - describes meaning of OSpace etc
// * http://stackoverflow.com/questions/22999330/mapping-from-iedmentity-to-clr

internal IList<EnumReference> FindEnumReferences(MetadataWorkspace metadataWorkspace)
{
// Get the part of the model that contains info about the actual CLR types
Expand Down Expand Up @@ -116,6 +122,7 @@ private static string GetColumnName(StructuralTypeMapping mappingFragment, EdmPr

propertyMapping = propertyMappings.Single();
}

return GetColumnNameFromPropertyMapping(edmProperty, propertyMapping);
}

Expand Down Expand Up @@ -144,88 +151,115 @@ private static PropertyMapping GetPropertyMapping(StructuralTypeMapping mappingF

private static MappingFragment FindSchemaMappingFragment(MetadataWorkspace metadata, EntityType entityType)
{
// refs:
// * http://romiller.com/2014/04/08/ef6-1-mapping-between-types-tables/
// * http://blogs.msdn.com/b/appfabriccat/archive/2010/10/22/metadataworkspace-reference-in-wcf-services.aspx
// * http://msdn.microsoft.com/en-us/library/system.data.metadata.edm.dataspace.aspx - describes meaning of OSpace etc
// * http://stackoverflow.com/questions/22999330/mapping-from-iedmentity-to-clr

// todo: break this function down into manageable chunks

try
{
// Get the entity type from the model that maps to the CLR type
var entityTypes = metadata
.GetItems<EntityType>(DataSpace.OSpace) // OSpace = Object Space
.Where(e => e == entityType)
.ToList();
if (entityTypes.Count() != 1)
{
throw new EnumGeneratorException(string.Format("{0} entities of type {1} found in mapping.", entityTypes.Count(),
entityType));
}
var entityMetadata = entityTypes.Single();

// Get the entity set that uses this entity type
var containers = metadata
.GetItems<EntityContainer>(DataSpace.CSpace); // CSpace = Conceptual model
if (containers.Count() != 1)
{
throw new EnumGeneratorException(string.Format("{0} EntityContainer's found.", containers.Count()));
}
var container = containers.Single();
var conceptualEntitySet = FindConceptualEntity(metadata, entityType);

var entitySets = container
.EntitySets
.Where(s => s.ElementType.Name == entityMetadata.Name)
.ToList();

// Child types in Table-per-Hierarchy don't have any mapping so return null for the table name. Foreign key will be created from the base type.
if (!entitySets.Any())
// Child types in Table-per-Hierarchy don't have any mappings defined as they don't add any new tables, so skip them.
if (conceptualEntitySet == null)
{
return null;
}
if (entitySets.Count() != 1)
{
throw new EnumGeneratorException(string.Format(
"{0} EntitySet's found for element type '{1}'.", entitySets.Count(), entityMetadata.Name));
}
var entitySet = entitySets.Single();

// Find the mapping between conceptual and storage model for this entity set
var entityContainerMappings = metadata.GetItems<EntityContainerMapping>(DataSpace.CSSpace);
// CSSpace = Conceptual model to Storage model mappings
if (entityContainerMappings.Count() != 1)
{
throw new EnumGeneratorException(string.Format("{0} EntityContainerMappings found.", entityContainerMappings.Count()));
}
var containerMapping = entityContainerMappings.Single();
var mappings = containerMapping.EntitySetMappings.Where(s => s.EntitySet == entitySet).ToList();
if (mappings.Count() != 1)
{
throw new EnumGeneratorException(string.Format(
"{0} EntitySetMappings found for entitySet '{1}'.", mappings.Count(), entitySet.Name));
}
var mapping = mappings.Single();

// Find the storage entity set (table) that the entity is mapped to
var entityTypeMappings = mapping.EntityTypeMappings;
var entityTypeMapping = entityTypeMappings.First();
// using First() because Table-per-Hierarchy (TPH) produces multiple copies of the entity type mapping
var fragments = entityTypeMapping.Fragments;
// <=== this contains the column mappings too. fragments.Items[x].PropertyMappings.Items[x].Column/Property
if (fragments.Count() != 1)
{
throw new EnumGeneratorException(string.Format("{0} Fragments found.", fragments.Count()));
}
var fragment = fragments.Single();
return fragment;
return FindStorageMappingFragmentFromConceptual(metadata, conceptualEntitySet);
}
catch (Exception exception)
{
throw new EnumGeneratorException(string.Format("Error getting schema mappings for entity type '{0}'", entityType.Name), exception);
}
}

private static EntitySet FindConceptualEntity(MetadataWorkspace metadata, EntityType entityType)
{
var entityMetadata = FindObjectSpaceEntityMetadata(metadata, entityType);

// Get the entity set that uses this entity type
var containers = metadata
.GetItems<EntityContainer>(DataSpace.CSpace); // CSpace = Conceptual model
if (containers.Count() != 1)
{
throw new EnumGeneratorException(string.Format("{0} EntityContainer's found.", containers.Count()));
}
var container = containers.Single();

var entitySets = container
.EntitySets
.Where(s => s.ElementType.Name == entityMetadata.Name)
// doesn't seem to be possible to get at the Object-Conceptual mappings from the public API so match on name.
.ToList();

// Child types in Table-per-Hierarchy don't have any mappings defined as they don't add any new tables, so skip them.
if (!entitySets.Any())
{
return null;
}

if (entitySets.Count() != 1)
{
throw new EnumGeneratorException(string.Format(
"{0} EntitySet's found for element type '{1}'.", entitySets.Count(), entityMetadata.Name));
}
var entitySet = entitySets.Single();

return entitySet;
}

private static EntityType FindObjectSpaceEntityMetadata(MetadataWorkspace metadata, EntityType entityType)
{
// Get the entity type from the model that maps to the CLR type
var entityTypes = metadata
.GetItems<EntityType>(DataSpace.OSpace) // OSpace = Object Space
.Where(e => e == entityType)
.ToList();
if (entityTypes.Count() != 1)
{
throw new EnumGeneratorException(string.Format("{0} entities of type {1} found in mapping.", entityTypes.Count(),
entityType));
}
var entityMetadata = entityTypes.Single();
return entityMetadata;
}

private static MappingFragment FindStorageMappingFragmentFromConceptual(MetadataWorkspace metadata, EntitySet conceptualEntitySet)
{
var storageMapping = FindStorageMapping(metadata, conceptualEntitySet);

return FindStorageMappingFragmentInStorageMapping(storageMapping);
}

private static MappingFragment FindStorageMappingFragmentInStorageMapping(EntitySetMapping storageMapping)
{
// Find the storage mapping fragment that the entity is mapped to
var entityTypeMappings = storageMapping.EntityTypeMappings;
var entityTypeMapping = entityTypeMappings.First();
// using First() because Table-per-Hierarchy (TPH) produces multiple copies of the entity type mapping
var fragments = entityTypeMapping.Fragments;
if (fragments.Count() != 1)
{
throw new EnumGeneratorException(string.Format("{0} Fragments found.", fragments.Count()));
}
var fragment = fragments.Single();
return fragment;
}

private static EntitySetMapping FindStorageMapping(MetadataWorkspace metadata, EntitySet conceptualEntitySet)
{
// Find the mapping between conceptual and storage model for this entity set
var entityContainerMappings = metadata.GetItems<EntityContainerMapping>(DataSpace.CSSpace);
// CSSpace = Conceptual model to Storage model mappings
if (entityContainerMappings.Count() != 1)
{
throw new EnumGeneratorException(string.Format("{0} EntityContainerMappings found.", entityContainerMappings.Count()));
}
var containerMapping = entityContainerMappings.Single();
var mappings = containerMapping.EntitySetMappings.Where(s => s.EntitySet == conceptualEntitySet).ToList();
if (mappings.Count() != 1)
{
throw new EnumGeneratorException(string.Format(
"{0} EntitySetMappings found for entitySet '{1}'.", mappings.Count(), conceptualEntitySet.Name));
}
var mapping = mappings.Single();
return mapping;
}
}
}

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