python mysql.connector DictCursor?

Question

In Python mysqldb I could declare a cursor as a dictionary cursor like this:

cursor = db.cursor(MySQLdb.cursors.DictCursor) 

This would enable me to reference columns in the cursor loop by name like this:

for row in cursor:   # Using the cursor as iterator 
    city = row["city"]
    state = row["state"]

Is it possible to create a dictionary cursor using this MySQL connector? http://dev.mysql.com/doc/connector-python/en/connector-python-example-cursor-select.html

Their example only returns a tuple.

I imagine the creators of MySQL would eventually do this for us?

Answer 1

According to this article it is available by passing in 'dictionary=True' to the cursor constructor: http://dev.mysql.com/doc/connector-python/en/connector-python-api-mysqlcursordict.html

so I tried:

cnx = mysql.connector.connect(database='bananas')
cursor = cnx.cursor(dictionary=True)

and got: TypeError: cursor() got an unexpected keyword argument 'dictionary'

and I tried:

cnx = mysql.connector.connect(database='bananas')
cursor = cnx.cursor(named_tuple=True)

and got: TypeError: cursor() got an unexpected keyword argument 'named_tuple'

and I tried this one too: cursor = MySQLCursorDict(cnx)

but to no avail. Clearly I'm on the wrong version here and I suspect we just have to be patient as the document at http://downloads.mysql.com/docs/connector-python-relnotes-en.a4.pdf suggests these new features are in alpha phase at point of writing.

Answer 2

A possible solution involves subclassing the MySQLCursor class like this:

class MySQLCursorDict(mysql.connector.cursor.MySQLCursor):
    def _row_to_python(self, rowdata, desc=None):
        row = super(MySQLCursorDict, self)._row_to_python(rowdata, desc)
        if row:
            return dict(zip(self.column_names, row))
        return None

db = mysql.connector.connect(user='root', database='test')

cursor = db.cursor(cursor_class=MySQLCursorDict)

Now the _row_to_python() method returns a dictionary instead of a tuple.

I found this on the mysql forum, and I believe it was posted by the mysql developers themselves. I hope they add it to the mysql connector package some day.

I tested this and it does work.

UPDATE: As mentioned below by Karl M.W... this subclass is no longer needed in v2 of the mysql.connector. The mysql.connector has been updated and now you can use the following option to enable a dictionary cursor.

cursor = db.cursor(dictionary=True)

Answer 3

This example works:

cnx = mysql.connector.connect(database='world')
cursor = cnx.cursor(dictionary=True)
cursor.execute("SELECT * FROM country WHERE Continent = 'Europe'")

print("Countries in Europe:")
for row in cursor:
    print("* {Name}".format(Name=row['Name']

Keep in mind that in this example, 'Name' is specific to the column name of the database being referenced.

Also, if you want to use stored procedures, do this instead:

cursor.callproc(stored_procedure_name, args)
result = []
for recordset in cursor.stored_results():
    for row in recordset:
        result.append(dict(zip(recordset.column_names,row)))

where stored_procedure_name is the name of the stored procedure to use and args is the list of arguments for that stored procedure (leave this field empty like [] if no arguments to pass in).

This is an example from the MySQL documentation found here: http://dev.mysql.com/doc/connector-python/en/connector-python-api-mysqlcursordict.html

Answer 4

Using Python 3.6.2 and MySQLdb version 1.3.10, I got this to work with:

import MySQLdb
import MySQLdb.cursors

...

conn = MySQLdb.connect(host='...', 
                       <connection info>, 
                       cursorclass=MySQLdb.cursors.DictCursor)

try:
    with conn.cursor() as cursor:
        query = '<SQL>'
        data = cursor.fetchall()
        for record in data:
            ... record['<field name>'] ...

finally:
    conn.close()

I'm using PyCharm, and simply dug into the MySQLdb modules connections.py and cursors.py.