Handling PyMySql exceptions - Best Practices
<p>My question regards exception best practices.
I'll present my question on a specific case with PyMySQL but it regards errors handling in general.
I am using PyMySQL and out of the many possible exceptions, there is one I want to deal with in a specific manner. "Duplicate" exception.</p>

<p>pymysql maps mysql errors to python errors according to the following table:</p>

<pre><code>_map_error(ProgrammingError, ER.DB_CREATE_EXISTS, ER.SYNTAX_ERROR,
       ER.PARSE_ERROR, ER.NO_SUCH_TABLE, ER.WRONG_DB_NAME,
       ER.WRONG_TABLE_NAME, ER.FIELD_SPECIFIED_TWICE,
       ER.INVALID_GROUP_FUNC_USE, ER.UNSUPPORTED_EXTENSION,
       ER.TABLE_MUST_HAVE_COLUMNS, ER.CANT_DO_THIS_DURING_AN_TRANSACTION)
_map_error(DataError, ER.WARN_DATA_TRUNCATED, ER.WARN_NULL_TO_NOTNULL,
       ER.WARN_DATA_OUT_OF_RANGE, ER.NO_DEFAULT, ER.PRIMARY_CANT_HAVE_NULL,
       ER.DATA_TOO_LONG, ER.DATETIME_FUNCTION_OVERFLOW)
_map_error(IntegrityError, ER.DUP_ENTRY, ER.NO_REFERENCED_ROW,
       ER.NO_REFERENCED_ROW_2, ER.ROW_IS_REFERENCED, ER.ROW_IS_REFERENCED_2,
       ER.CANNOT_ADD_FOREIGN, ER.BAD_NULL_ERROR)
_map_error(NotSupportedError, ER.WARNING_NOT_COMPLETE_ROLLBACK,
       ER.NOT_SUPPORTED_YET, ER.FEATURE_DISABLED, ER.UNKNOWN_STORAGE_ENGINE)
_map_error(OperationalError, ER.DBACCESS_DENIED_ERROR, ER.ACCESS_DENIED_ERROR,
       ER.CON_COUNT_ERROR, ER.TABLEACCESS_DENIED_ERROR,
       ER.COLUMNACCESS_DENIED_ERROR)
</code></pre>

<p>I want to specifically catch ER.DUP_ENTRY but I only know how to catch IntegrityError and that leads to redundant cases within my exception catch.</p>

<pre><code>cur.execute(query, values)
except IntegrityError as e:
     if e and e[0] == PYMYSQL_DUPLICATE_ERROR:
          handel_duplicate_pymysql_exception(e, func_a)
     else:
          handel_unknown_pymysql_exception(e, func_b)
except Exception as e:
     handel_unknown_pymysql_exception(e, func_b)
</code></pre>

<p>Is there a way to simply catch only ER.DUP_ENTRY some how?
looking for something like:</p>

<pre><code>except IntegrityError.DUP_ENTRY as e:
     handel_duplicate_pymysql_exception(e, func_a)
</code></pre>

<p>Thanks in advance for your guidance,</p>