private static void UpdateManyToManyForeignKeys(this SQLiteConnection conn, object element, PropertyInfo relationshipProperty)
{
var type = element.GetType();
EnclosedType enclosedType;
var entityType = relationshipProperty.GetEntityType(out enclosedType);
var currentEntityPrimaryKeyProperty = type.GetPrimaryKey();
var otherEntityPrimaryKeyProperty = entityType.GetPrimaryKey();
var manyToManyMetaInfo = type.GetManyToManyMetaInfo(relationshipProperty);
var currentEntityForeignKeyProperty = manyToManyMetaInfo.OriginProperty;
var otherEntityForeignKeyProperty = manyToManyMetaInfo.DestinationProperty;
var intermediateType = manyToManyMetaInfo.IntermediateType;
Assert(enclosedType != EnclosedType.None, type, relationshipProperty, "ManyToMany relationship must be a List or Array");
Assert(currentEntityPrimaryKeyProperty != null, type, relationshipProperty, "ManyToMany relationship origin must have Primary Key");
Assert(otherEntityPrimaryKeyProperty != null, type, relationshipProperty, "ManyToMany relationship destination must have Primary Key");
Assert(intermediateType != null, type, relationshipProperty, "ManyToMany relationship intermediate type cannot be null");
Assert(currentEntityForeignKeyProperty != null, type, relationshipProperty, "ManyToMany relationship origin must have a foreign key defined in the intermediate type");
Assert(otherEntityForeignKeyProperty != null, type, relationshipProperty, "ManyToMany relationship destination must have a foreign key defined in the intermediate type");
var primaryKey = currentEntityPrimaryKeyProperty.GetValue(element, null);
// Obtain the list of children keys
var childList = (IEnumerable)relationshipProperty.GetValue(element, null);
var childKeyList = (from object child in childList ?? new List <object>()
select otherEntityPrimaryKeyProperty.GetValue(child, null)).ToList();
// Check for already existing relationships
var childrenPlaceHolders = string.Join(",", Enumerable.Repeat("?", childKeyList.Count));
var currentChildrenQuery = string.Format("select [{0}] from [{1}] where [{2}] == ? and [{0}] in ({3})",
otherEntityForeignKeyProperty.GetColumnName(), intermediateType.GetTableName(), currentEntityForeignKeyProperty.GetColumnName(), childrenPlaceHolders);
var parameters = new List <object> {
primaryKey
};
parameters.AddRange(childKeyList);
var currentChildKeyList =
from object child in conn.Query(conn.GetMapping(intermediateType), currentChildrenQuery, parameters.ToArray())
select otherEntityForeignKeyProperty.GetValue(child, null);
// Insert missing relationships in the intermediate table
var missingChildKeyList = childKeyList.Where(o => !currentChildKeyList.Contains(o)).ToList();
var missingIntermediateObjects = new List <object>(missingChildKeyList.Count);
foreach (var missingChildKey in missingChildKeyList)
{
var intermediateObject = Activator.CreateInstance(intermediateType);
currentEntityForeignKeyProperty.SetValue(intermediateObject, primaryKey, null);
otherEntityForeignKeyProperty.SetValue(intermediateObject, missingChildKey, null);
missingIntermediateObjects.Add(intermediateObject);
}
conn.InsertAll(missingIntermediateObjects);
// Delete any other pending relationship
var deleteQuery = string.Format("delete from [{0}] where [{1}] == ? and [{2}] not in ({3})",
intermediateType.GetTableName(), currentEntityForeignKeyProperty.GetColumnName(),
otherEntityForeignKeyProperty.GetColumnName(), childrenPlaceHolders);
conn.Execute(deleteQuery, parameters.ToArray());
}