BUG: Should allow numeric mysql table/column names

Doc fix

Author: Artemy Kolchinsky

doc/source/whatsnew/v0.16.2.txt

@@ -88,3 +88,5 @@ Bug Fixes
 - Bug where infer_freq infers timerule (WOM-5XXX) unsupported by to_offset (:issue:`9425`)
 
 - Bug to handle masking empty ``DataFrame``(:issue:`10126`)
+- Bug where MySQL interface could not handle numeric table/column names (:issue:`10255`)
+

pandas/io/sql.py

@@ -1283,8 +1283,6 @@ def _get_valid_mysql_name(name):
         if not re.match(basere, c):
             if not (0x80 < ord(c) < 0xFFFF):
                 raise ValueError("Invalid MySQL identifier '%s'" % uname)
-    if not re.match(r'[^0-9]', uname):
-        raise ValueError('MySQL identifier cannot be entirely numeric')
 
     return '`' + uname + '`'
 

pandas/io/tests/test_sql.py

@@ -1738,7 +1738,8 @@ def test_illegal_names(self):
 
         for ndx, weird_name in enumerate(['test_weird_name]','test_weird_name[',
             'test_weird_name`','test_weird_name"', 'test_weird_name\'',
-            '_b.test_weird_name_01-30', '"_b.test_weird_name_01-30"']):
+            '_b.test_weird_name_01-30', '"_b.test_weird_name_01-30"',
+            '12345','12345blah']):
             df.to_sql(weird_name, self.conn, flavor=self.flavor)
             sql.table_exists(weird_name, self.conn)
 
@@ -1839,16 +1840,30 @@ def test_to_sql_save_index(self):
         self._to_sql_save_index()
 
     def test_illegal_names(self):
+        df = DataFrame([[1, 2], [3, 4]], columns=['a', 'b'])
+
+        # These tables and columns should be ok
+        for ndx, ok_name in enumerate(['99beginswithnumber','12345']):
+            df.to_sql(ok_name, self.conn, flavor=self.flavor, index=False,
+                      if_exists='replace')
+            self.conn.cursor().execute("DROP TABLE `%s`" % ok_name)
+            self.conn.commit()
+            df2 = DataFrame([[1, 2], [3, 4]], columns=['a', ok_name])
+            c_tbl = 'test_ok_col_name%d'%ndx
+            df2.to_sql(c_tbl, self.conn, flavor=self.flavor, index=False,
+                      if_exists='replace')   
+            self.conn.cursor().execute("DROP TABLE `%s`" % c_tbl)
+            self.conn.commit()
+
         # For MySQL, these should raise ValueError
         for ndx, illegal_name in enumerate(['test_illegal_name]','test_illegal_name[',
             'test_illegal_name`','test_illegal_name"', 'test_illegal_name\'', '']):
-            df = DataFrame([[1, 2], [3, 4]], columns=['a', 'b'])
             self.assertRaises(ValueError, df.to_sql, illegal_name, self.conn,
                 flavor=self.flavor, index=False)
 
             df2 = DataFrame([[1, 2], [3, 4]], columns=['a', illegal_name])
             c_tbl = 'test_illegal_col_name%d'%ndx
-            self.assertRaises(ValueError, df2.to_sql, 'test_illegal_col_name',
+            self.assertRaises(ValueError, df2.to_sql, c_tbl,
                 self.conn, flavor=self.flavor, index=False)