Reserved MySQL keywords as field names result in syntax errors on string restriction

[CBroz1]

Bug Report

Description

There are no guardrails in place to prevent a user from declaring a field called 'match', for example, which will require escaping in order to perform string restrictions.

Reproducibility

Include:

• OS Linux
• Python Version 3.9.18
• MySQL Version 8.0.34
• MySQL Deployment Strategy (local-native | local-docker | remote)
• DataJoint Version 0.14.3
• Minimum number of steps to reliably reproduce the issue
• Complete error stack as a result of evaluating the above steps

Reproduction

import datajoint as dj

schema = dj.schema("temp")


@schema
class BadField(dj.Lookup):
    definition = """
    id: int
    ---
    match : bool
    """
    contents = [(1, True), (2, False), (3, True)]


if __name__ == "__main__":
    print(BadField() & "id = 1")
    print(BadField() & "`match` = 1")
    print(BadField() & "match = 1")

Error stack

I [77]: run temp.py
*id    match
+----+ +-------+
1      1
 (Total: 1)

*id    match
+----+ +-------+
1      1
3      1
 (Total: 2)

---------------------------------------------------------------------------
QuerySyntaxError                          Traceback (most recent call last)
File ~/wrk/spyglass/temp-btl.py:19
     17 print(BadField() & "id = 1")
     18 print(BadField() & "`match` = 1")
---> 19 print(BadField() & "match = 1")

File ~/miniconda3/envs/rio/lib/python3.9/site-packages/datajoint/expression.py:671, in QueryExpression.__repr__(self)
    660 def __repr__(self):
    661     """
    662     returns the string representation of a QueryExpression object e.g. ``str(q1)``.
    663
   (...)
    666     :rtype: str
    667     """
    668     return (
    669         super().__repr__()
    670         if config["loglevel"].lower() == "debug"
--> 671         else self.preview()
    672     )

File ~/miniconda3/envs/rio/lib/python3.9/site-packages/datajoint/expression.py:676, in QueryExpression.preview(self, limit, width)
    674 def preview(self, limit=None, width=None):
    675     """:return: a string of preview of the contents of the query."""
--> 676     return preview(self, limit, width)

File ~/miniconda3/envs/rio/lib/python3.9/site-packages/datajoint/preview.py:13, in preview(query_expression, limit, width)
     11 if width is None:
     12     width = config["display.width"]
---> 13 tuples = rel.fetch(limit=limit + 1, format="array")
     14 has_more = len(tuples) > limit
     15 tuples = tuples[:limit]

File ~/miniconda3/envs/rio/lib/python3.9/site-packages/datajoint/fetch.py:236, in Fetch.__call__(self, offset, limit, order_by, format, as_dict, squeeze, download_path, *attrs)
    234         ret = return_values[0] if len(attrs) == 1 else return_values
    235 else:  # fetch all attributes as a numpy.record_array or pandas.DataFrame
--> 236     cur = self._expression.cursor(as_dict=as_dict)
    237     heading = self._expression.heading
    238     if as_dict:

File ~/miniconda3/envs/rio/lib/python3.9/site-packages/datajoint/expression.py:658, in QueryExpression.cursor(self, as_dict)
    656 sql = self.make_sql()
    657 logger.debug(sql)
--> 658 return self.connection.query(sql, as_dict=as_dict)

File ~/miniconda3/envs/rio/lib/python3.9/site-packages/datajoint/connection.py:343, in Connection.query(self, query, args, as_dict, suppress_warnings, reconnect)
    341 cursor = self._conn.cursor(cursor=cursor_class)
    342 try:
--> 343     self._execute_query(cursor, query, args, suppress_warnings)
    344 except errors.LostConnectionError:
    345     if not reconnect:

File ~/miniconda3/envs/rio/lib/python3.9/site-packages/datajoint/connection.py:299, in Connection._execute_query(cursor, query, args, suppress_warnings)
    297         cursor.execute(query, args)
    298 except client.err.Error as err:
--> 299     raise translate_query_error(err, query)

QuerySyntaxError: ("You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '= 1)) ORDER BY `id` LIMIT 13' at line 1", 'SELECT `id`,`match` FROM `cbroz_temp`.`#bad_field` WHERE ( (match = 1)) ORDER BY `id` LIMIT 13')

Expected Behavior

A naive user might not be familiar with SQL keywords and expect the following to behave similarly.

MyTable & 'my_field = 1' # works, no reserved keyword
MyTable & {'match':1} # works, escaped keyword
MyTable & 'match = 1'

DataJoint could potentially...

1. prevent field names like this, and raise an error similar to using underscores in table names
2. escape field names in string restrictions
3. on SyntaxError, scan the where clause for reserved keywords and suggest the user restrict with a dictionary instead.

Screenshots

n/a

Additional Research and Context

n/a

[dimitri-yatsenko]

This is a known problem that has been raised from time to time. DataJoint does not prevent users from using attribute names that are reserved words in MySQL, e.g. key, select, signal. Our decision was to address this correctly in all cases where datajoint has control over the syntax (e.g. declarations and queries), but not in cases where the user supplies their own SQL conditions as strings. This should be addressed in the documentation or perhaps in the error message.