diff --git a/ingestify/application/dataset_store.py b/ingestify/application/dataset_store.py
index e2032aa..f2c1934 100644
--- a/ingestify/application/dataset_store.py
+++ b/ingestify/application/dataset_store.py
@@ -17,6 +17,7 @@
     Dataset,
     DatasetCollection,
     DatasetRepository,
+    DatasetResource,
     DraftFile,
     File,
     LoadedFile,
@@ -205,14 +206,14 @@ def add_revision(
     def update_dataset(
         self,
         dataset: Dataset,
-        dataset_identifier: Identifier,
+        dataset_resource: DatasetResource,
         files: Dict[str, DraftFile],
     ):
         """The add_revision will also save the dataset."""
         metadata_changed = False
-        # if dataset.update_from_identifier(dataset_identifier):
-        #     self.dataset_repository.save(bucket=self.bucket, dataset=dataset)
-        #     metadata_changed = True
+        if dataset.update_from_resource(dataset_resource):
+            self.dataset_repository.save(bucket=self.bucket, dataset=dataset)
+            metadata_changed = True
 
         self.add_revision(dataset, files)
 
diff --git a/ingestify/application/loader.py b/ingestify/application/loader.py
index 4131f3e..4b69b14 100644
--- a/ingestify/application/loader.py
+++ b/ingestify/application/loader.py
@@ -25,7 +25,7 @@
 logger = logging.getLogger(__name__)
 
 
-DEFAULT_CHUNK_SIZE = 100
+DEFAULT_CHUNK_SIZE = 1000
 
 
 def to_batches(input_):
@@ -52,7 +52,8 @@ def load_file(
             file_resource.file_id
         )
 
-    if file_resource.json_content:
+    if file_resource.json_content is not None:
+        # Empty dictionary is allowed
         return DraftFile.from_input(
             file_=json.dumps(file_resource.json_content, indent=4),
             data_serialization_format="json",
@@ -93,7 +94,7 @@ def __init__(
     def run(self):
         self.store.update_dataset(
             dataset=self.dataset,
-            dataset_identifier=Identifier(self.dataset_resource.dataset_resource_id),
+            dataset_resource=self.dataset_resource,
             files={
                 file_id: load_file(file_resource, dataset=self.dataset)
                 for file_id, file_resource in self.dataset_resource.files.items()
diff --git a/ingestify/domain/models/dataset/dataset.py b/ingestify/domain/models/dataset/dataset.py
index d39bd05..a1309b3 100644
--- a/ingestify/domain/models/dataset/dataset.py
+++ b/ingestify/domain/models/dataset/dataset.py
@@ -53,18 +53,18 @@ def add_revision(self, revision: Revision):
         self.revisions.append(revision)
         self.updated_at = utcnow()
 
-    def update_from_identifier(self, dataset_identifier: Identifier) -> bool:
+    def update_from_resource(self, dataset_resource) -> bool:
         changed = False
-        if self.name != dataset_identifier.name:
-            self.name = dataset_identifier.name
+        if self.name != dataset_resource.name:
+            self.name = dataset_resource.name
             changed = True
 
-        if self.metadata != dataset_identifier.metadata:
-            self.metadata = dataset_identifier.metadata
+        if self.metadata != dataset_resource.metadata:
+            self.metadata = dataset_resource.metadata
             changed = True
 
-        if self.state != dataset_identifier.state:
-            self.state = dataset_identifier.state
+        if self.state != dataset_resource.state:
+            self.state = dataset_resource.state
             changed = True
 
         if changed:
diff --git a/ingestify/domain/models/resources/dataset_resource.py b/ingestify/domain/models/resources/dataset_resource.py
index b447b6e..67e8d4d 100644
--- a/ingestify/domain/models/resources/dataset_resource.py
+++ b/ingestify/domain/models/resources/dataset_resource.py
@@ -2,6 +2,8 @@
 from datetime import datetime
 from typing import Optional, Callable, TYPE_CHECKING
 
+from ingestify.exceptions import DuplicateFile
+
 if TYPE_CHECKING:
     from ingestify.domain import DraftFile, File
     from ingestify.domain.models.dataset.dataset import DatasetState
@@ -28,6 +30,12 @@ class FileResource:
         Callable[["FileResource", Optional["File"]], Optional["DraftFile"]]
     ] = None
 
+    def __post_init__(self):
+        if self.json_content is None and not self.url and not self.file_loader:
+            raise TypeError(
+                "You need to specify `json_content`, `url` or a custom `file_loader`"
+            )
+
 
 class DatasetResource:
     def __init__(
@@ -55,7 +63,8 @@ def add_file(
         self,
         last_modified: datetime,
         data_feed_key: str,
-        data_spec_version: str,
+        # Some sources might not have a DataSpecVersion. Set a default
+        data_spec_version: str = "v1",
         json_content: Optional[dict] = None,
         url: Optional[str] = None,
         http_options: Optional[dict] = None,