fix: Column name mapping in missing left/right (#12)

Author: MariusMerkleQC

sqlcompyre/analysis/schema_comparison.py

@@ -77,6 +77,7 @@ def table_names(self) -> Names:
         return Names(
             left=set(self.left_tables.keys()),
             right=set(self.right_tables.keys()),
+            name_mapping=None,
             ignore_casing=self.ignore_casing,
         )
 

sqlcompyre/analysis/table_comparison.py

@@ -156,6 +156,7 @@ def column_names(self) -> Names:
         return Names(
             left={col.name for col in self.left_table.columns},
             right={col.name for col in self.right_table.columns},
+            name_mapping=self.column_name_mapping,
             ignore_casing=self.ignore_casing,
         )
 

sqlcompyre/results/names.py

@@ -7,11 +7,18 @@
 class Names:
     """Investigate the names of database objects."""
 
-    def __init__(self, left: set[str], right: set[str], ignore_casing: bool):
+    def __init__(
+        self,
+        left: set[str],
+        right: set[str],
+        name_mapping: dict[str, str] | None,
+        ignore_casing: bool,
+    ):
         """
         Args:
             left: Names from the "left" database object.
             right: Names from the "right" database object.
+            name_mapping: Mapping from the "left" to the "right" database object.
             ignore_casing: Whether to ignore casing for name equality.
         """
         if ignore_casing:
@@ -20,6 +27,10 @@ def __init__(self, left: set[str], right: set[str], ignore_casing: bool):
         else:
             self._set_left = left
             self._set_right = right
+        self._name_mapping = name_mapping
+        self._inverse_name_mapping = (
+            {v: k for k, v in name_mapping.items()} if name_mapping else {}
+        )
 
     @cached_property
     def left(self) -> list[str]:
@@ -39,12 +50,22 @@ def in_common(self) -> list[str]:
     @cached_property
     def missing_left(self) -> list[str]:
         """Ordered list of names provided only by the "right" database object."""
-        return sorted(self._set_right - self._set_left)
+        if self._name_mapping:
+            right_renamed = {
+                self._inverse_name_mapping.get(k, k) for k in self._set_right
+            }
+            return sorted(right_renamed - self._set_left)
+        else:
+            return sorted(self._set_right - self._set_left)
 
     @cached_property
     def missing_right(self) -> list[str]:
         """Ordered list of names provided only by the "left" database object."""
-        return sorted(self._set_left - self._set_right)
+        if self._name_mapping:
+            left_renamed = {self._name_mapping.get(k, k) for k in self._set_left}
+            return sorted(left_renamed - self._set_right)
+        else:
+            return sorted(self._set_left - self._set_right)
 
     @cached_property
     def equal(self) -> bool:

tests/analysis/table_comparison/test_column_matching.py

@@ -89,8 +89,8 @@ def test_partly_renaming(
         column_name_mapping={"age": "age_v2", "gpa": "gpa_v2"},
     )
     assert len(comparison.column_names.in_common) == 2
-    assert len(comparison.column_names.missing_left) == 2
-    assert len(comparison.column_names.missing_right) == 2
+    assert len(comparison.column_names.missing_left) == 0
+    assert len(comparison.column_names.missing_right) == 0
     assert comparison.row_counts.diff == 1
     # Ensure that all columns are matched, one is primary key, 3 per table left
     assert pd.read_sql(comparison.row_matches.joined_equal, con=engine).shape[1] == 7
@@ -102,8 +102,8 @@ def test_partly_renaming(
         column_name_mapping={"age_v2": "age", "gpa_v2": "gpa"},
     )
     assert len(comparison.column_names.in_common) == 2
-    assert len(comparison.column_names.missing_left) == 2
-    assert len(comparison.column_names.missing_right) == 2
+    assert len(comparison.column_names.missing_left) == 0
+    assert len(comparison.column_names.missing_right) == 0
     assert comparison.row_counts.diff == 1
     # Ensure that all columns are matched, one is primary key, 3 per table left
     assert pd.read_sql(comparison.row_matches.joined_equal, con=engine).shape[1] == 7

tests/report/formatters/conftest.py

@@ -20,7 +20,10 @@ def metadata_description() -> Metadata:
 @pytest.fixture()
 def names() -> Names:
     return Names(
-        left={"hello", "world"}, right={"hello", "hi", "there"}, ignore_casing=False
+        left={"hello", "world"},
+        right={"hello", "hi", "there"},
+        name_mapping=None,
+        ignore_casing=False,
     )