Python sqlite3 错误-executemany function

Question

I am importing data from text file,

1, A1, chicago.

2, B1, NY.

3, K2, LA.

d=open('file.txt','r')
data=d.readlines()
data1=[]
for items in data:
    data1=items.split()
    #print(data1)
    stmt = "INSERT INTO Student1 VALUES (?,?,?)"
    cu.executemany(stmt, data1)```


I am getting this error.
cu.executemany(stmt, data1)
sqlite3.ProgrammingError: Incorrect number of bindings supplied. The current statement uses 4, and there are 2 supplied.

Answer 1

To use "executemany" you need to pass list of tuples:

conn = sqlite3.connect('test.db')
cu = conn.cursor()
d = open('file.txt', 'r')
data = d.readlines()
data1 = []
for items in data:
    data1 += [items.split()]
stmt = "INSERT INTO Student1 VALUES (?,?,?,?)"
cu.executemany(stmt, data1)
conn.commit()

Use executemany to insert list of rows. Or change to "execute"

for items in data:
    data1=items.split()
    #print(data1)
    stmt = "INSERT INTO Student1 VALUES (?,?,?)"
    cu.execute(stmt, data1)

Answer 2

executemany() this function needs second parameter as list of tuples in python. data1 variable in your code is list without tuples. you can use something like following.

import sqlite3
d=open('file.txt','r')
data=d.readlines()
data1=[]
data1_in_list_of_tuple = []
for items in data:
    data1=items.split()
    data1_in_list_of_tuple.append(tuple(data1))
stmt = "INSERT INTO Student1 VALUES (?,?,?)"
cu.executemany(stmt, data1_in_list_of_tuple)

Answer 3

Since you are only inserting one student at a time, use cursor.execute instead.

Create the data (basically equivalent to reading the file):

In [1]: txt = '''1, A1, chicago.
   ...: 2, B1, NY.
   ...: 3, K2, LA.'''
Out[1]: '1, A1, chicago.\n2, B1, NY.\n3, K2, LA.'

In [2]: data = txt.splitlines()
Out[2]: ['1, A1, chicago.', '2, B1, NY.', '3, K2, LA.']

For correct data handling;

• Remove the . at the end of each line.
• split on the , ,
• strip all the parts.

Let's test how to do that:

In [4]: item = [j.strip() for j in data[0][:-1].split(",")]
Out[4]: ['1', 'A1', 'chicago']

This looks OK.

Create database and table (note that I've made up field names):

In [5]: import sqlite3

In [6]: con = sqlite3.connect(':memory:')
Out[6]: <sqlite3.Connection at 0x80414cd50>

In [7]: cur = con.cursor()
Out[7]: <sqlite3.Cursor at 0x8041aab20>

In [8]: cur.execute("CREATE TABLE Student1 (num INTEGER, grade TEXT, location TEXT)")
Out[8]: <sqlite3.Cursor at 0x8041aab20>

Now we can insert all the students:

In [9]: for line in data:
   ...:     items = tuple(j.strip() for j in line[:-1].split(","))
   ...:     cur.execute("INSERT INTO Student1 VALUES (?,?,?)", items)
   ...:    

Check that it worked:

In [10]: for row in cur.execute("SELECT * FROM Student1"):
    ...:     print(row)
    ...:     
(1, 'A1', 'chicago')
(2, 'B1', 'NY')
(3, 'K2', 'LA')