Is there an exception in my pymysql insert statement below that I can use here to pass on looping if the value already exists?
My code looks like:
try:
with db.cursor() as cursor:
sqltld = "INSERT INTO `table`(`colname`) VALUES (%s)"
cursor.execute(sqltld, (self.url))
db.commit()
except:
print("error INSERTing url")
db.rollback()
Mysql is already enforcing unique on the column colname
Thanks
Related
I am trying to insert Arduino data into a database through Python, however, it will not do it. Basically I am assigning data that I read in from the serial port assigned to my Arduino and storing the first value of it in the variable arduinoData. in my insert statement I am trying to use a string literal to put the arduinoData into the table. Here is the code:
import mysql.connector
from mysql.connector import errorcode
from time import sleep
import serial
# Obtain connection string information from the portal
config = {
'host':'oursystem.mysql.database.azure.com',
'user':'project',
'password':'',
'database':'projectdb'
}
# Construct connection string
try:
conn = mysql.connector.connect(**config)
print("Connection established")
except mysql.connector.Error as err:
if err.errno == errorcode.ER_ACCESS_DENIED_ERROR:
print("Something is wrong with the user name or password")
elif err.errno == errorcode.ER_BAD_DB_ERROR:
print("Database does not exist")
else:
print(err)
else:
cursor = conn.cursor()
ser = serial.Serial('/dev/ttyACM0', 9600) # Establish the connection on a specific port
arduinoData=ser.read().strip()
print arduinoData
# Drop previous table of same name if one exists
cursor.execute("DROP TABLE IF EXISTS ArduinoData;")
print("Finished dropping table (if existed).")
# Create table
cursor.execute("CREATE TABLE ArduinoData (value VARCHAR(20));")
print("Finished creating table.")
# Insert some data into table
cursor.execute("INSERT INTO ArduinoData (value) VALUES (%s);",(arduinoData))
print("Inserted",cursor.rowcount,"row(s) of data.")
# Cleanup
conn.commit()
cursor.close()
conn.close()
print("Done.")
If I put the %s in single quotes like '%s' it just prints that instead of my arduinoData. Can anyone see what is wrong here, thanks.
I just lost two hours on this :
If you're trying to observe what's happening to your database with phpmyadmin, please note that all your insert commands won't be visible until you commit them
connection.commit()
Simply pass a tuple (arduinoData,) which means a comma within parentheses for a single value or list [arduinoData] and not a single value (arduinoData) in your parameterization:
cursor.execute("INSERT INTO ArduinoData (`value`) VALUES (%s);",(arduinoData,))
However if arduinoData is a list of multiple values, then use executemany, still passing a list. Also, escape value which is a MySQL reserved word:
cursor.executemany("INSERT INTO ArduinoData (`value`) VALUES (%s);",[arduinoData])
I may have interpreted this wrong but, shouldn't there be something like certain_value = '%s' otherwise it doesn't know what it is looking for.
I have just figured out what was wrong, using Parfait's suggestion of parsing a tuple, i just changed my insert statement from cursor.execute("INSERT INTO ArduinoData (value) VALUES (%s);",(arduinoData))to cursor.execute("INSERT INTO ArduinoData (value) VALUES (%s);",(arduinoData,))thanks to everyone who answered you were all a great help! :D
When I'm using pymysql to perform operations on MySQL database, it seems that all the operations are temporary and only visible to the pymysql connection, which means I can only see the changes through cur.execute('select * from qiushi') and once I cur.close() and conn.close() and log back in using pymysql, everything seems unchanged.
However, when I'm looking at the incremental id numbers, it does increased, but I can't see the rows that were inserted from pymysql connection. It seems that they were automatically deleted?!
Some of my code is here:
import pymysql
try:
conn = pymysql.connect(host='127.0.0.1',port=3306,user='pymysql',passwd='pymysql',charset='utf8')
cur = conn.cursor()
#cur.execute('CREATE TABLE qiushi (id INT NOT NULL AUTO_INCREMENT, content_id BIGINT(10) NOT NULL, content VARCHAR(1000), created TIMESTAMP DEFAULT CURRENT_TIMESTAMP, PRIMARY KEY(id));')
#cur.execute('DESCRIBE content')
#cur.fetchall()
cur.execute('USE qiushibaike')
for _ in range(0,len(content_ids)):
cur.execute("INSERT INTO qiushi (content,content_id) VALUES (\"%s\",%d)"%(jokes[_],int(content_ids[_])))
finally:
cur.close()
conn.close()
I solved the problem by myself...
Because the config is automatically committed, so after each SQL sentence we should commit the changes.
Approach 1:
add cur.commit() after the cur.execute()
Approach 2:
edit the connection config, add autocommit=True
I'm having problems returning auto-incremented ID columns from a MySQL database using MySQLdb python library.
I have something like:
sql = """INSERT INTO %s (%s) VALUES (\"%s\")""" %(tbl, colsf, valsf)
try:
cursor.execute(sql)
id = cursor.lastrowid
db.close()
except:
print "Failed to add to MySQL database: \n%s" %sql
print sys.exc_info()
db.close()
exit()
However the lastrowid command seems to be returning incorrect values. For instance, I've tried printing out various id columns from the MySQL command line which shows them to be empty, but the lastrowid value keeps increasing by 1 every time the python script is run. Any ideas?
Turned out that the values weren't being committed to the MySQL database properly, adding "db.commit()" command seems to solve the problem.
sql = """INSERT INTO %s (%s) VALUES (\"%s\")""" %(tbl, colsf, valsf)
try:
cursor.execute(sql)
id = cursor.lastrowid
cursor.close()
db.commit()
db.close()
except:
print "Failed to add to MySQL database: \n%s" %sql
print sys.exc_info()
db.close()
exit()
I want to run the create function in a tkinter interface but it give me this error:
1064 (42000): You have an error in your SQL syntax; check the manual
that corresponds to your MySQL server version for the right syntax to
use near ''' (id INT NOT NULL AUTO_INCREMENT,cash INT,dt DATE, PRIMARY
KEY(id))' at line 1
This is the code. I have tried a lot of thinks but nothing...
from mysql.connector import MySQLConnection, Error
from tkinter import *
DB_HOST = 'localhost'
DB_USER = 'root'
DB_PASS = 'mysql123'
DB_NAME = 'Savings'
def create(Name):
try:
connection = MySQLConnection(host=DB_HOST,user=DB_USER,password=DB_PASS,database=DB_NAME)
cursor = connection.cursor()
tabla = Name.get()
cursor.execute("CREATE TABLE %s (id INT NOT NULL AUTO_INCREMENT,cash INT,dt DATE, PRIMARY KEY(id))", (tabla,))
print("Hecho!")
except Error as e:
print(e)
finally:
connection.commit()
cursor.close()
connection.close()
You cannot parameterize table or column names. Use string formatting (but make sure you trust your source or validate the input table name carefully):
cursor.execute("CREATE TABLE {table} (id INT NOT NULL AUTO_INCREMENT,cash INT,dt DATE, PRIMARY KEY(id))".format(table=tabla))
Note that you can use the mysql connector to escape strings:
tabla = connection.converter.escape(tabla)
I am inserting a couple thousand records into a table via the python code below:
values = ''
for row in cursor:
values = values + "(" + self.quoted_comma_separate(row) + "),"
values = values[:-1]
insert_statement = "INSERT INTO t1 ({0}) VALUES {1};".format(
self.comma_separate(members), values)
db = Database()
conn = db.get_db()
cursor = conn.cursor()
cursor.execute(insert_statement)
conn.commit()
conn.close()
When I check the database after it runs none of the records show up in the database. If I go into an MySQL editor and manually commit the transaction all of the records appear. Why is my conn.commit() not working?
The insert statements were fine. Turns out I had another database connection open and it was getting confused and committing to the wrong connection or something like that. Sorry for the pointless question :)