Merge f7220ee into 209b9b1

graphql_compiler/schema_generation/sqlalchemy/schema_graph_builder.py

@@ -9,7 +9,9 @@
 from .edge_descriptors import validate_edge_descriptors
 from .scalar_type_mapper import try_get_graphql_scalar_type
 from .utils import (
-    validate_that_tables_belong_to_the_same_metadata_object, validate_that_tables_have_primary_keys
+    validate_that_sqlalchemy_tables_have_a_single_vertex_name,
+    validate_that_tables_belong_to_the_same_metadata_object,
+    validate_that_tables_have_primary_keys
 )
 
 
@@ -35,6 +37,7 @@ def get_sqlalchemy_schema_graph(vertex_name_to_table, direct_edges):
     validate_that_tables_belong_to_the_same_metadata_object(vertex_name_to_table.values())
     validate_edge_descriptors(vertex_name_to_table, direct_edges)
     validate_that_tables_have_primary_keys(vertex_name_to_table.values())
+    validate_that_sqlalchemy_tables_have_a_single_vertex_name(vertex_name_to_table)
 
     vertex_types = {
         vertex_name: _get_vertex_type_from_sqlalchemy_table(vertex_name, table)

graphql_compiler/schema_generation/sqlalchemy/utils.py

@@ -14,6 +14,19 @@ def validate_that_tables_have_primary_keys(tables):
                                          .format(table.name, table.schema))
 
 
+def validate_that_sqlalchemy_tables_have_a_single_vertex_name(vertex_name_to_table):
+    """Validate that each SQLAlchemy Table has only one corresponding vertex type name."""
+    table_to_vertex_name = {}
+
+    for vertex_name, table in vertex_name_to_table.items():
+        if table in table_to_vertex_name:
+            other_vertex_name = vertex_name_to_table[table]
+            raise AssertionError('Table {} is associated with multiple vertex types: {} and {}.'
+                                 .format(table.fullname, vertex_name, other_vertex_name))
+        else:
+            table_to_vertex_name[table] = vertex_name
+
+
 def validate_that_tables_belong_to_the_same_metadata_object(tables):
     """Validate that all the SQLAlchemy Table objects belong to the same MetaData object."""
     metadata = None