Insert values into SQL column with mysql-python

Question

I am trying to insert values into a column of a SQL table, using MySQLdb in Python 2.7. I am having problems with the command to insert a list into 1 column.

I have a simple table called 'name' as shown below:

+--------+-----------+----------+--------+
| nameid | firstname | lastname | TopAdd |
+--------+-----------+----------+--------+
| 1      | Cookie    | Monster  |        |
| 2      | Guy       | Smiley   |        |
| 3      | Big       | Bird     |        |
| 4      | Oscar     | Grouch   |        |
| 5      | Alastair  | Cookie   |        |
+--------+-----------+----------+--------+

Here is how I created the table:

CREATE TABLE `name` (
  `nameid` int(11) NOT NULL AUTO_INCREMENT,
  `firstname` varchar(45) DEFAULT NULL,
  `lastname` varchar(45) DEFAULT NULL,
  `TopAdd` varchar(40) NOT NULL,
  PRIMARY KEY (`nameid`)
) ENGINE=InnoDB AUTO_INCREMENT=16 DEFAULT CHARSET=utf8

Here is how I populated the table:

INSERT INTO `test`.`name`
(`firstname`,`lastname`)
VALUES
("Cookie","Monster"),
("Guy","Smiley"),
("Big","Bird"),
("Oscar","Grouch"),
("Alastair","Cookie");

DISCLAIMER: The original source for the above MySQL example is here .

Here is how I created the a new column named TopAdd:

ALTER TABLE name ADD TopAdd VARCHAR(40) NOT NULL

I now have a list of 5 values that I would like to insert into the column TopAdd as the values of that column. Here is the list.

vals_list = ['aa','bb','cc','dd','ee']

Here is what I have tried (UPDATE statement inside loop):

vals = tuple(vals_list)
for self.ijk in range (0,len(self.vals)):
            self.cursor.execute ("UPDATE name SET TopAdd = %s WHERE 'nameid' = %s" % (self.vals[self.ijk],self.ijk+1))

I get the following error message:

Traceback (most recent call last):
  File "C:\Python27\mySQLdbClass.py", line 70, in <module>
    [Finished in 0.2s with exit code 1]main()
  File "C:\Python27\mySQLdbClass.py", line 66, in main
    db.mysqlconnect()
  File "C:\Python27\mySQLdbClass.py", line 22, in mysqlconnect
    self.cursor.execute ("UPDATE name SET TopAdd = %s WHERE 'nameid' = %s" % (self.vals[self.ijk],self.ijk+1))
  File "C:\Python27\lib\site-packages\MySQLdb\cursors.py", line 205, in execute
    self.errorhandler(self, exc, value)
  File "C:\Python27\lib\site-packages\MySQLdb\connections.py", line 36, in defaulterrorhandler
    raise errorclass, errorvalue
_mysql_exceptions.OperationalError: (1054, "Unknown column 'aa' in 'field list'")

Is there a way to insert these values into the column with a loop or directly as a list?

Answer 1

Try This:

vals_list = ['aa','bb','cc','dd','ee']

for i, j in enumerate(vals_list):

 self.cursor.execute(("UPDATE test.name SET TopAdd = '%s' WHERE nameid = %s" % (str(j),int(i+1))

Answer 2

One problem is here:

for self.ijk in range (0,len(self.vals)):

The range function is creating a list of integers (presumably, the list [0, 1, 2, 3, 4] ). When iterating over a collection in a for loop, you bind each successive item in the collection to a name; you do not access them as attributes of an instance . (It also seems appropriate to use xrange here; see xrange vs range .) So the self reference is non-sensical; beyond that, ijk is a terrible name for an integer value, and there's no need to supply the default start value of zero. KISS :

for i in range(len(self.vals)):

Not only does this make your line shorter (and thus easier to read), using i to represent an integer value in a loop is a convention that's well understood. Now we come to another problem:

self.cursor.execute ("UPDATE name SET TopAdd = %s WHERE 'nameid' = %s" % (self.vals[self.ijk],self.ijk+1))

You're not properly parameterizing your query here. Do not follow this advice , which may fix your current error but leaves your code prone to wasted debugging time at best, SQL injection and/or data integrity issues at worst. Instead, replace the % with a comma so that the execute function does the work safely quoting and escaping parameters for you.

With that change, and minus the quotation marks around your column name, nameid :

query = "UPDATE name SET TopAdd = %s WHERE nameid = %s;"
for i in range(len(self.vals)):
    self.cursor.execute(query, (self.vals[i], i + 1))

Should work as expected. You can still use enumerate as suggested by the other answer, but there's no reason to go around typecasting everything in sight; enumerate is documented and gives exactly the types you already want:

for i, val in enumerate(self.vals):
    self.cursor.execute(query, (val, i + 1))