如何与 Python-Mysql 交互

Question

I have done the following code and I would like to ask the user to input how many new records want and after to fill column by column those records.

import MySQLdb

import mysql.connector

mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="Adam!977",
  database="testdb1"

)

cur = mydb.cursor()

get_tables_statement = """SHOW TABLES"""
cur.execute(get_tables_statement)
tables = cur.fetchall()
table = tables(gene)        
x=input("How many records you desire: ")
x
print "Please enter the data you would like to insert into table %s" %(table)
columns = []
values = []
for j in xrange(0, len(gene)):
    column = gene[j][0]
    value = raw_input("Value to insert for column '%s'?"%(gene[j][0]))
    columns.append(str(column))
    values.append('"' + str(value) + '"')
columns = ','.join(columns)
values = ','.join(values)
print columns
print values

The error that i get is about table gene( The table exist in db of SQL) Traceback (most recent call last): File "C:\\Users\\Admin\\Desktop\\π.py", line 25, in table = tables(gene) NameError: name 'gene' is not defined

Also, even I don't know if working properly the code. Please, I need help. Thank you

Answer 1

The error being returned by python is down to the lack of definition of a variable gene . In the following line you reference gene , without it existing:

table = tables(gene)

In the documentation for the python mysql connector, under cursor.fetchall() you'll notice that this method returns either a list of tuples or an empty list. It is therefore somewhat puzzling why you call tables as a function and attempt to pass a parameter to it - this is not correct syntax for accessing a list, or a tuple.

At the beginning of your code example you fetch a list of all of the tables in your database, despite knowing that you only want to update a specific table. It would make more sense to simply reference the name of the table in your SQL query, rather than querying all of the tables that exist and then in python selecting one. For example, the following query would give you 10 records from the table 'gene':

SELECT * FROM gene LIMIT 10

Below is an attempt to correct your code:

import mysql.connector

mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="Adam!977",
  database="testdb1"

)

x=input("How many records you desire: ")
cur = mydb.cursor()

get_rows_statement = """SELECT * FROM gene"""
cur.execute(get_rows_statement)
results = cur.fetchall()

This should give you all of the rows within the table.