style: Apply pre-commit formatting fixes

- Collapse multi-line statements for readability (ruff-format)
- Consistent quote style (' vs ")
- Remove unused import (os from test_cascade_delete.py)
- Add blank line after import for PEP 8 compliance

All formatting changes from pre-commit hooks (ruff, ruff-format).

Author: dimitri-yatsenko

src/datajoint/declare.py

@@ -291,7 +291,7 @@ def compile_foreign_key(
     # Extract database and table name and rebuild with current adapter
     parent_full_name = ref.support[0]
     # Try to parse as database.table (with or without quotes)
-    parts = parent_full_name.replace('"', '').replace('`', '').split('.')
+    parts = parent_full_name.replace('"', "").replace("`", "").split(".")
     if len(parts) == 2:
         ref_table_name = f"{adapter.quote_identifier(parts[0])}.{adapter.quote_identifier(parts[1])}"
     else:

src/datajoint/heading.py

@@ -369,9 +369,7 @@ def _init_from_database(self) -> None:
             as_dict=True,
         ).fetchone()
         if info is None:
-            raise DataJointError(
-                f"The table {database}.{table_name} is not defined."
-            )
+            raise DataJointError(f"The table {database}.{table_name} is not defined.")
         # Normalize table_comment to comment for backward compatibility
         self._table_status = {k.lower(): v for k, v in info.items()}
         if "table_comment" in self._table_status:
@@ -592,9 +590,7 @@ def select(self, select_list, rename_map=None, compute_map=None):
                     dict(
                         self.attributes[old_name].todict(),
                         name=new_name,
-                        attribute_expression=(
-                            adapter.quote_identifier(old_name) if adapter else f"`{old_name}`"
-                        ),
+                        attribute_expression=(adapter.quote_identifier(old_name) if adapter else f"`{old_name}`"),
                     )
                     for new_name, old_name in rename_map.items()
                     if old_name == name

src/datajoint/table.py

@@ -372,9 +372,7 @@ def is_declared(self):
         """
         :return: True is the table is declared in the schema.
         """
-        query = self.connection.adapter.get_table_info_sql(
-            self.database, self.table_name
-        )
+        query = self.connection.adapter.get_table_info_sql(self.database, self.table_name)
         return self.connection.query(query).rowcount > 0
 
     @property
@@ -896,7 +894,7 @@ def cascade(table):
                         ) from None
 
                     # Strip quotes from parsed values for backend-agnostic processing
-                    quote_chars = ('`', '"')
+                    quote_chars = ("`", '"')
 
                     def strip_quotes(s):
                         if s and any(s.startswith(q) for q in quote_chars):
@@ -928,9 +926,7 @@ def strip_quotes(s):
                             args=(strip_quotes(match["name"]), child_schema, child_table_name),
                         ).fetchall()
                         if results:
-                            match["fk_attrs"], match["parent"], match["pk_attrs"] = list(
-                                map(list, zip(*results))
-                            )
+                            match["fk_attrs"], match["parent"], match["pk_attrs"] = list(map(list, zip(*results)))
                             match["parent"] = match["parent"][0]  # All rows have same parent
 
                     # Build properly quoted full table name for FreeTable

tests/integration/test_cascade_delete.py

@@ -2,8 +2,6 @@
 Integration tests for cascade delete on multiple backends.
 """
 
-import os
-
 import pytest
 
 import datajoint as dj
@@ -15,6 +13,7 @@ def schema_by_backend(connection_by_backend, db_creds_by_backend, request):
     backend = db_creds_by_backend["backend"]
     # Use unique schema name for each test
     import time
+
     test_id = str(int(time.time() * 1000))[-8:]  # Last 8 digits of timestamp
     schema_name = f"djtest_cascade_{backend}_{test_id}"[:64]  # Limit length