Rock.Model.AttributeValueService.GetByAttributeId C# (CSharp) Method

        public IQueryable<AttributeValue> GetByAttributeId( int attributeId )
        {
            return Queryable().Where( t => t.AttributeId == attributeId );
        }

        /// <summary>
        /// Loads Rock data that's used globally by the transform
        /// </summary>
        private void LoadExistingRockData()
        {
            var attributeValueService = new AttributeValueService();
            var attributeService = new AttributeService();

            IntegerFieldTypeId = FieldTypeCache.Read( new Guid( Rock.SystemGuid.FieldType.INTEGER ) ).Id;
            TextFieldTypeId = FieldTypeCache.Read( new Guid( Rock.SystemGuid.FieldType.TEXT ) ).Id;
            PersonEntityTypeId = EntityTypeCache.Read( "Rock.Model.Person" ).Id;
            BatchEntityTypeId = EntityTypeCache.Read( "Rock.Model.FinancialBatch" ).Id;

            var personAttributes = attributeService.GetByEntityTypeId( PersonEntityTypeId ).ToList();

            var householdAttribute = personAttributes.FirstOrDefault( a => a.Key == "F1HouseholdId" );
            if ( householdAttribute == null )
            {
                householdAttribute = new Rock.Model.Attribute();
                householdAttribute.Key = "F1HouseholdId";
                householdAttribute.Name = "F1 Household Id";
                householdAttribute.FieldTypeId = IntegerFieldTypeId;
                householdAttribute.EntityTypeId = PersonEntityTypeId;
                householdAttribute.EntityTypeQualifierValue = string.Empty;
                householdAttribute.EntityTypeQualifierColumn = string.Empty;
                householdAttribute.Description = "The FellowshipOne household identifier for the person that was imported";
                householdAttribute.DefaultValue = string.Empty;
                householdAttribute.IsMultiValue = false;
                householdAttribute.IsRequired = false;
                householdAttribute.Order = 0;

                attributeService.Add( householdAttribute, ImportPersonAlias );
                attributeService.Save( householdAttribute, ImportPersonAlias );
                personAttributes.Add( householdAttribute );
            }

            var individualAttribute = personAttributes.FirstOrDefault( a => a.Key == "F1IndividualId" );
            if ( individualAttribute == null )
            {
                individualAttribute = new Rock.Model.Attribute();
                individualAttribute.Key = "F1IndividualId";
                individualAttribute.Name = "F1 Individual Id";
                individualAttribute.FieldTypeId = IntegerFieldTypeId;
                individualAttribute.EntityTypeId = PersonEntityTypeId;
                individualAttribute.EntityTypeQualifierValue = string.Empty;
                individualAttribute.EntityTypeQualifierColumn = string.Empty;
                individualAttribute.Description = "The FellowshipOne individual identifier for the person that was imported";
                individualAttribute.DefaultValue = string.Empty;
                individualAttribute.IsMultiValue = false;
                individualAttribute.IsRequired = false;
                individualAttribute.Order = 0;

                attributeService.Add( individualAttribute, ImportPersonAlias );
                attributeService.Save( individualAttribute, ImportPersonAlias );
                personAttributes.Add( individualAttribute );
            }

            IndividualAttributeId = individualAttribute.Id;
            HouseholdAttributeId = householdAttribute.Id;

            ReportProgress( 0, "Checking for existing people..." );
            var listHouseholdId = attributeValueService.GetByAttributeId( householdAttribute.Id ).Select( av => new { PersonId = av.EntityId, HouseholdId = av.Value } ).ToList();
            var listIndividualId = attributeValueService.GetByAttributeId( individualAttribute.Id ).Select( av => new { PersonId = av.EntityId, IndividualId = av.Value } ).ToList();

            ImportedPeople = listHouseholdId.GroupJoin( listIndividualId, household => household.PersonId,
                individual => individual.PersonId, ( household, individual ) => new ImportedPerson
                {
                    PersonId = household.PersonId,
                    HouseholdId = household.HouseholdId.AsType<int?>(),
                    IndividualId = individual.Select( i => i.IndividualId.AsType<int?>() ).FirstOrDefault()
                } ).ToList();

            var batchAttribute = attributeService.Queryable().FirstOrDefault( a => a.EntityTypeId == BatchEntityTypeId
                && a.Key == "F1BatchId" );
            if ( batchAttribute == null )
            {
                batchAttribute = new Rock.Model.Attribute();
                batchAttribute.Key = "F1BatchId";
                batchAttribute.Name = "F1 Batch Id";
                batchAttribute.FieldTypeId = IntegerFieldTypeId;
                batchAttribute.EntityTypeId = BatchEntityTypeId;
                batchAttribute.EntityTypeQualifierValue = string.Empty;
                batchAttribute.EntityTypeQualifierColumn = string.Empty;
                batchAttribute.Description = "The FellowshipOne identifier for the batch that was imported";
                batchAttribute.DefaultValue = string.Empty;
                batchAttribute.IsMultiValue = false;
                batchAttribute.IsRequired = false;
                batchAttribute.Order = 0;

                attributeService.Add( batchAttribute, ImportPersonAlias );
                attributeService.Save( batchAttribute, ImportPersonAlias );
            }

            BatchAttributeId = batchAttribute.Id;

            ReportProgress( 0, "Checking for existing contributions..." );
            ImportedBatches = new AttributeValueService().GetByAttributeId( batchAttribute.Id )
                .Select( av => new { F1BatchId = av.Value.AsType<int?>(), RockBatchId = av.EntityId } )
                .ToDictionary( t => t.F1BatchId, t => t.RockBatchId );

            CampusList = new CampusService().Queryable().ToList();
        }