Merge pull request #8180 from jorisvandenbossche/sql-7815-casesens

SQL: add warning for mismatch in provided and written table name (GH7815)

Author: jorisvandenbossche

pandas/io/sql.py

@@ -886,6 +886,12 @@ def to_sql(self, frame, name, if_exists='fail', index=True,
             name, self, frame=frame, index=index, if_exists=if_exists,
             index_label=index_label, schema=schema)
         table.insert(chunksize)
+        # check for potentially case sensitivity issues (GH7815)
+        if name not in self.engine.table_names(schema=schema or self.meta.schema):
+            warnings.warn("The provided table name '{0}' is not found exactly "
+                          "as such in the database after writing the table, "
+                          "possibly due to case sensitivity issues. Consider "
+                          "using lower case table names.".format(name), UserWarning)
 
     @property
     def tables(self):

pandas/io/tests/test_sql.py

@@ -681,6 +681,19 @@ def test_not_reflect_all_tables(self):
             # Verify some things
             self.assertEqual(len(w), 0, "Warning triggered for other table")
 
+    def test_warning_case_insensitive_table_name(self):
+        # see GH7815.
+        # We can't test that this warning is triggered, a the database
+        # configuration would have to be altered. But here we test that
+        # the warning is certainly NOT triggered in a normal case.
+        with warnings.catch_warnings(record=True) as w:
+            # Cause all warnings to always be triggered.
+            warnings.simplefilter("always")
+            # This should not trigger a Warning
+            self.test_frame1.to_sql('CaseSensitive', self.conn)
+            # Verify some things
+            self.assertEqual(len(w), 0, "Warning triggered for writing a table")
+
 
 class TestSQLLegacyApi(_TestSQLApi):
     """