How to understand how python executes database query operations

This article mainly explains "how to understand python to execute database query operation". The content of the article is simple and clear, and it is easy to learn and understand. Please follow the editor's train of thought to study and learn "how to understand python to execute database query operation".

1. Fetchone this method gets the next query result set. The result set is an object.

2. Fetchall receives all the returned result rows.

3. Rowcount this is a read-only property and returns the number of rows affected after the execution of the execute method.

Example

From pymysql import * def main (): # create a Connection connection conn = connect (host='localhost',port=3306,user='root',password='mysql',database='jing_dong',charset='utf8') # get the Cursor object cs1 = conn.cursor () # execute the select statement And return the number of affected rows: query a piece of data count = cs1.execute ('select id,name from goods where id > = 4') # print the number of affected rows print ("query% d pieces of data:"% count) for i in range (count): # get the result of the query result = cs1.fetchone () # print the result of the query print (result) # tuple (1 'Zhang San', 20, 'male') # get the result of the query # close the Cursor object cs1.close () conn.close () if _ _ name__ = ='_ main__': main ()

Instance expansion:

#! / usr/bin/python# filename conn.pyimport MySQLdb # load the connection database module try: # attempt to connect to the database conn = MySQLdb.connect ("localhost", "root", "www", "yao", charset= "utf8") # define the information except MySQLdb.OperationalError to connect to the database Message: # connection failure prompt print "link error" cursor=conn.cursor () # define connection object cursor.execute ("select * from user") # use the method provided by cursor to execute the query statement data=cursor.fetchall () # use the fetchall method to return all query results print data # print query results cursor.close () # close the cursor object Conn.close () # close the database link. Thank you for reading. The above is the content of "how to understand the query operation of the database by python". After the study of this article, I believe you have a deeper understanding of how to understand the query operation of the database by python, and the specific use needs to be verified in practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!