Python MySQL database of pymysql connection module (1)

01Python Login .py

username = input ( "Enter the user name:") 
pwd = the INPUT ( "Please enter your password:") 

# IF username == "ERGE" and pwd == "dashabi": 
# Print ( "! successful landing") 
# the else: 
# print ( "roll ~") 


with Open ( "userinfo.txt", "R & lt", encoding = "UTF-. 8") AS F: 
    for in Line F: 
        # Print (line.strip ()) 
        U, P = . line.strip () Split ( "|") 
        IF U == == username and the p-pwd: 
            Print ( "! successful landing") 
            BREAK 
    the else: 
        Print ( "Go OUT ~") 


02Python connect to the database login .py

pymysql Import 

username = the INPUT ( "Enter the user name:") 
pwd = the INPUT ( "Please enter your password:") 

# IF username == "ERGE" and pwd == "dashabi": 
# Print ( "successful landing!") 
# the else: 
# Print ( "roll ~") 

# get user name of the user entered password 

# determines which database to the user name and password are correct 
# 1 connected to the database 
Conn = pymysql.connect ( 
    Host = "localhost", 
    Port = 3306, # port number is numeric 
    database = "userinfo", # write your own local database name of 
    the User = "root", 
    password = "123456", 
    charset = "utf8" # always remember that no - 
) 

the Cursor = conn.cursor () # get input SQL statement cursor object 
SQL = "info from the SELECT *;" 
RET = the cursor.Execute (SQL) 
Print (RET) 
# close the connection 
cursor.close () 
conn.Close ()


2. Analyzing # -> only need to write the sql statement search condition, a database to be performed on a 

# with Open ( "userinfo.txt", "R & lt", encoding = "UTF-. 8") AS F: 
# f Line in for: 
# # Print (line.strip ()) 
. # U, the p-line.strip = () Split ( "|") 
# IF U == == username and the p-pwd: 
# Print ( "successful landing ! ") 
# BREAK 
# the else: 
# Print (" Go OUT ~ ") 


03 Login check MySQL.py

pymysql Import 

# get user input 
username = input ( "Enter the user name:") 
pwd = the INPUT ( "Please enter your password:") 


# there is no connection to the database to retrieve the user 
conn = pymysql.connect ( 
    Host = "localhost", 
    Port = 3306, 
    Database = "UserInfo", 
    the User = "root", 
    password = "123456", 
    charset = "utf8" 
) 

the cursor = conn.cursor () # get the cursor 
SQL statement to be executed mosaic # 
sql = "select * from info username = WHERE '% S' and password = '% S' "% (username, pwd) 
Print (SQL) 
Print (" = "120 *) 
# execute SQL statements 
RET = the cursor.execute (SQL) 
IF RET: 
    Print ( "Login successful") 
the else: 
    Print ( "Login failed!") 
# Close a cursor image 
cursor.close () 
# close the connection 
conn.Close ()

04 Log check MySQL avoid SQL injection .py

pymysql Import 

# get user input 
username = input ( "Enter the user name:") 
pwd = the INPUT ( "Please enter your password:") 


# there is no connection to the database to retrieve the user 
conn = pymysql.connect ( 
    Host = "localhost", 
    Port = 3306, 
    Database = "UserInfo", 
    the User = "root", 
    password = "123456", 
    charset = "utf8" 
) 

the cursor = conn.cursor () # get the cursor 
SQL statement to be executed mosaic # 
sql = 'select * from info username =% S and the WHERE password =% S ' 
Print (SQL) 
Print ( "=" * 120) 
# execute SQL statements 
ret = cursor.execute (sql, [username , pwd]) # let us help pymysql stitching SQL statements 
if RET: 
    Print ( "Login successful") 
the else: 
    Print ( "Login failed!") 
# Close a cursor image 
cursor.close () 
# close the connection
conn.Close () 

05pymysql by operation .py

"" " 
Pymysql-increment 
" "" 

Import pymysql 

Conn = pymysql.connect ( 
    Host = "localhost", 
    Port = 3306, 
    Database = "UserInfo", 
    User = "the root", 
    password = "123456", 
    charset = "UTF8" 
) 

Cursor = conn.cursor () 

# splicing statement 
SQL = "INSERT INTO info (username, password) the VALUES (% S,% S)" 
# execute 
the try: 
    the cursor.execute (SQL, [ "big Xu"]) 
    # write your own for loop (today operating under its own test) 
    conn.commit () 
the except Exception AS E: 
    Print ( "error Rights:", str (E)) 
    conn.rollback () rollback # 
# write to the database to do a certain operation remember to submit assword 

the Cursor.use Close () 
conn.Close () 

06 demo lastrowid what's the use .py

pymysql Import 

Conn = pymysql.connect ( 
    Host = "localhost", 
    Port = 3306, 
    Database = "UserInfo", 
    User = "the root", 
    password = "123456", 
    charset = "UTF8" 
) 

Cursor = conn.cursor () 
# create a class sql statement 
SQL1 = "INSERT INTO class (name) VALUES (% S)" 
# students create sql statement 
SQL2 = "INSERT INTO student (name, cid) VALUES (% S,% S)" 


cursor.execute ( sql1, "full-stack 9") 
NEW_ID ID = cursor.lastrowid # Get the value of the newly inserted data 
cursor.execute (sql2, [ "small Northeast", NEW_ID]) 

conn.commit () 
cursor.close () 
conn.Close () 

07 bulk insert data .py

pymysql Import 

Conn = pymysql.connect ( 
    Host = "localhost", 
    Port = 3306, 
    Database = "UserInfo", 
    User = "the root", 
    password = "123456", 
    charset = "UTF8" 
) 

Cursor = conn.cursor () 
# create class sql statement 
sql = "INSERT INTO info (username, password) the VALUES (% S,% S)" 

Data = [( "alex1", "dashabi"), ( "dirty Sir1",), ( "xiaoyima1 " , "nvshen")] 
the try: 
    cursor.executemany (SQL, the Data) # internals for circulating, batch execution insert statement 
    # for i in the Data: 
    # cursor.execute (SQL, i) 
    conn.commit () # submitted once 
except AS E Exception: 
    Print ( "You're wrong!") 
    conn.ROLLBACK () 

cursor.close () 
conn.Close () 

08 deletes data manipulation .py

import pymysql

conn = pymysql.connect(
    host="localhost",
    port=3306,
    database="userinfo",
    user="root",
    password="123456",
    charset="utf8"
)

cursor = conn.cursor()

# sql = "delete from info WHERE username=%s"
sql = "delete from info WHERE id=%s"

cursor.execute(sql,8)

conn.commit()
cursor.close()
conn.close()