private static bool UpdateColumnNamesForTableSharing(
DbDatabaseMapping databaseMapping, EdmEntityType entityType, DbTableMetadata toTable,
DbEntityTypeMappingFragment fragment)
{
// Validate: this table can be used only if:
// 1. The table is not used by any other type
// 2. The table is used only by types in the same type hierarchy (TPH)
// 3. There is a 1:1 relationship and the PK count and types match (Table Splitting)
var typesSharingTable = FindAllTypesUsingTable(databaseMapping, toTable);
var associationsToSharedTable = new Dictionary<EdmEntityType, List<EdmAssociationType>>();
foreach (var candidateType in typesSharingTable)
{
var oneToOneAssocations = FindAllOneToOneFKAssociationTypes(
databaseMapping.Model, entityType, candidateType);
var rootType = candidateType.GetRootType();
if (!associationsToSharedTable.ContainsKey(rootType))
{
associationsToSharedTable.Add(rootType, oneToOneAssocations.ToList());
}
else
{
associationsToSharedTable[rootType].AddRange(oneToOneAssocations);
}
}
foreach (var candidateTypePair in associationsToSharedTable)
{
// Check if these types are in a TPH hierarchy
if (candidateTypePair.Key != entityType.GetRootType()
&&
candidateTypePair.Value.Count == 0)
{
var tableName = toTable.GetTableName();
throw Error.EntityMappingConfiguration_InvalidTableSharing(
entityType.Name, candidateTypePair.Key.Name,
tableName != null ? tableName.Name : toTable.DatabaseIdentifier);
}
}
var allAssociations = associationsToSharedTable.Values.SelectMany(l => l);
if (allAssociations.Any())
{
var principalKeyNamesType = toTable.GetKeyNamesType();
if (principalKeyNamesType == null)
{
// grab a candidate
var association = allAssociations.First();
principalKeyNamesType = association.Constraint.PrincipalEnd(association).EntityType;
if (allAssociations.All(x => x.Constraint.PrincipalEnd(x).EntityType == principalKeyNamesType))
{
toTable.SetKeyNamesType(principalKeyNamesType);
}
}
// rename the columns in the fragment to match the principal keys
var principalKeys = principalKeyNamesType.KeyProperties().ToArray();
var i = 0;
foreach (var k in entityType.KeyProperties())
{
var dependentColumn = fragment.PropertyMappings.Single(pm => pm.PropertyPath.First() == k).Column;
dependentColumn.Name = principalKeys[i].Name;
i++;
}
return true;
}
return false;
}
