def _sql_type_name(self, col):
        dtype = self.dtype or {}
        if col.name in dtype:
            return dtype[col.name]

        col_type = self._get_notnull_col_dtype(col)
        if col_type == 'timedelta64':
            warnings.warn("the 'timedelta' type is not supported, and will be "
                          "written as integer values (ns frequency) to the "
                          "database.", UserWarning, stacklevel=8)
            col_type = "integer"

        elif col_type == "datetime64":
            col_type = "datetime"

        elif col_type == "empty":
            col_type = "string"

        elif col_type == "complex":
            raise ValueError('Complex datatypes not supported')

        if col_type not in _SQL_TYPES:
            col_type = "string"

        return _SQL_TYPES[col_type][self.pd_sql.flavor]
dataset/ETHPy150Open pydata/pandas/pandas/io/sql.py/SQLiteTable._sql_type_name/original