sql.py 文件源码

def to_sql(self, frame, name, if_exists='fail', index=True,
               index_label=None, schema=None, chunksize=None, dtype=None):
        """
        Write records stored in a DataFrame to a SQL database.

        Parameters
        ----------
        frame : DataFrame
        name : string
            Name of SQL table
        if_exists : {'fail', 'replace', 'append'}, default 'fail'
            - fail: If table exists, do nothing.
            - replace: If table exists, drop it, recreate it, and insert data.
            - append: If table exists, insert data. Create if does not exist.
        index : boolean, default True
            Write DataFrame index as a column
        index_label : string or sequence, default None
            Column label for index column(s). If None is given (default) and
            `index` is True, then the index names are used.
            A sequence should be given if the DataFrame uses MultiIndex.
        schema : string, default None
            Name of SQL schema in database to write to (if database flavor
            supports this). If specified, this overwrites the default
            schema of the SQLDatabase object.
        chunksize : int, default None
            If not None, then rows will be written in batches of this size at a
            time.  If None, all rows will be written at once.
        dtype : dict of column name to SQL type, default None
            Optional specifying the datatype for columns. The SQL type should
            be a SQLAlchemy type.

        """
        if dtype is not None:
            from sqlalchemy.types import to_instance, TypeEngine
            for col, my_type in dtype.items():
                if not isinstance(to_instance(my_type), TypeEngine):
                    raise ValueError('The type of %s is not a SQLAlchemy '
                                     'type ' % col)

        table = SQLTable(name, self, frame=frame, index=index,
                         if_exists=if_exists, index_label=index_label,
                         schema=schema, dtype=dtype)
        table.create()
        table.insert(chunksize)
        # check for potentially case sensitivity issues (GH7815)
        engine = self.connectable.engine
        with self.connectable.connect() as conn:
            table_names = engine.table_names(
                schema=schema or self.meta.schema,
                connection=conn,
            )
        if name not in table_names:
            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)