Row - mkleehammer/pyodbc GitHub Wiki

Row objects are returned from Cursor fetch functions. As specified in the DB API, they are tuple-like.

row = cursor.fetchone()
print(row[0])

However, there are some pyodbc additions that make them very convenient:

• Values can be accessed by column name.
• The Cursor.description values can be accessed even after the cursor is closed.
• Values can be replaced.
• Rows from the same select statement share memory.

Accessing rows by column name is very convenient, readable, and Pythonish:

cursor.execute("select album_id, photo_id from photos where user_id=1")
row = cursor.fetchone()
print(row.album_id, row.photo_id)
print(row[0], row[1])  # same as above, but less readable

This will not work if the column name is an invalid Python label (e.g. contains a space or is a Python reserved word), but you can still accessed by name using row.__getattribute__('My Value').

Having access to the cursor's description even after the cursor is closed makes Rows very convenient data structures - you can pass them around and they are self describing:

def getuser(userid):
    cnxn = pyodbc.connect(...)
    cursor = cnxn.cursor()
    return cursor.execute("""
                          select album_id, photo_id 
                            from photos
                           where user_id = ?
                          """, userid).fetchall()

row = getuser(7)
# At this point the cursor has been closed and deleted
# But the columns and datatypes can still be access:
print('columns:', ', '.join(t[0] for t in row.cursor_description))

Unlike normal tuples, values in Row objects can be replaced. (This means you shouldn't use rows as dictionary keys!)

The intention is to make Rows convenient data structures to replace small or short-lived classes. While SQL is powerful, there are sometimes slight changes that need to be made after reading values:

# Replace the 'start_date' datetime in each row with one that has a time zone.
rows = cursor.fetchall()
for row in rows:
    row.start_date = row.start_date.astimezone(tz)

Note that slicing rows returns tuples, not Row objects!

Attributes

cursor_description

A copy of the Cursor.description object from the Cursor that created this row. This contains the column names and data types of the columns. See Cursor.description