[Database] add some helper functions

database.py

@@ -63,6 +63,16 @@ class Dataset(dj.Manual):
             sane = False
         return sane
 
+    @property
+    def cells(self, restrictions:dict=None):
+        cs = (Cell & (CellDatasetMap & self) & restrictions).fetch()
+        return cs
+
+    @property
+    def subjects(self, restrictions:dict=None):
+        subjs = (Subject & (SubjectDatasetMap & self) & restrictions).fetch()
+        return subjs
+
 
 @schema
 class Subject(dj.Manual):
@@ -98,6 +108,14 @@ class Subject(dj.Manual):
         self.insert1(inserts, skip_duplicates=True)
         nix_file.close()
 
+    @staticmethod
+    def subjects(species=None):
+        subjs = []
+        if species:
+            subjs = (Subject & "species like '\%%s\%'"%species).fetch()
+        else:
+            subjs = (Subject & True).fetch()
+        return subjs
 
 @schema
 class SubjectDatasetMap(dj.Manual):