Trying Python today for the first time today and got stuck following and example almost immediately. Using Pyhon 3.6 on Windows. Can someone help?
RESTART: C:/Users/tom_/AppData/Local/Programs/Python/Python36-32/Projects/Database/dbexample.py
Traceback (most recent call last):
File "C:/Users/tom_/AppData/Local/Programs/Python/Python36-32/Projects/Database/dbexample.py", line 13, in <module>
enter_data()
File "C:/Users/tom_/AppData/Local/Programs/Python/Python36-32/Projects/Database/dbexample.py", line 11, in enter_data
c.execute("INSERT INTO Example VALUES('Python', 2.7, 'Beginner')")
sqlite3.OperationalError: no such table: Example
Code:
import sqlite3
conn = sqlite3.connect('tutorial.db')
c = conn.cursor()
def create_table():
c.execute("CREATE TABLE Example(Language VARCHAR, Version REAL, Skill TEXT)")
def enter_data():
c.execute("INSERT INTO Example VALUES('Python', 2.7, 'Beginner')")
enter_data()
conn.close()
you need to call create_table() once before you can use enter_data() for a new db.
Once it has been created you will get a sqlite3.OperationalError: table Example already exists if you call it again.
Related
I want to delete rows based on a datetime filter.
I created a table with DateTime column without timezone using similar script.
class VolumeInfo(Base):
...
date: datetime.datetime = Column(DateTime, nullable=False)
Then I try to delete rows using such filter
days_interval = 10
to_date = datetime.datetime.combine(
datetime.datetime.utcnow().date(),
datetime.time(0, 0, 0, 0),
).replace(tzinfo=None)
from_date = to_date - datetime.timedelta(days=days_interval)
query = delete(VolumeInfo).where(Volume.date < from_date)
Unexpectedly, sometimes there is no error, but sometimes there is the error:
Traceback (most recent call last):
...
File "script.py", line 381, in delete_volumes
db.execute(query)
File "/usr/local/lib/python3.10/site-packages/sqlalchemy/orm/session.py", line 1660, in execute
) = compile_state_cls.orm_pre_session_exec(
File "/usr/local/lib/python3.10/site-packages/sqlalchemy/orm/persistence.py", line 1843, in orm_pre_session_exec
update_options = cls._do_pre_synchronize_evaluate(
File "/usr/local/lib/python3.10/site-packages/sqlalchemy/orm/persistence.py", line 2007, in _do_pre_synchronize_evaluate
matched_objects = [
File "/usr/local/lib/python3.10/site-packages/sqlalchemy/orm/persistence.py", line 2012, in <listcomp>
and eval_condition(state.obj())
File "/usr/local/lib/python3.10/site-packages/sqlalchemy/orm/evaluator.py", line 211, in evaluate
return operator(eval_left(obj), eval_right(obj))
TypeError: can't compare offset-naive and offset-aware datetimes
Using python3.10 in docker (image python:3.10-slim) and postgreSQL database with psycopg2 driver.
I have already tried all possible options, but this error appears every once in a while
How can i solve this? or where I made a mistake?
UPD1:
I keep getting an error with Pandas' 0.25.0 read_sql(). The code below is supposed to establish a couple connections, check if tables need to be created, and then begin extracting the result set from Oracle.
Stack Trace
RESTART: C:\xxxx\xxxx\AppData\Local\Programs\Python\Python36\xxxx\main.py
Creating connections
Attempting to connect
Connection to box_db Successful
Attempting to connect
Connection to JDE Successful
Box table already existed
BoxStaging table already existed
LotStartSiteMap table already existed
Extracting from JDE
Traceback (most recent call last):
File "C:\xxxx\xxxx\AppData\Local\Programs\Python\Python36\xxxx\main.py", line 42, in <module>
main()
File "C:\xxxx\xxxx\AppData\Local\Programs\Python\Python36\xxxx\main.py", line 26, in main
df = data.box_data_extract(queries.BOX_QUERY, jde_conn)
File "C:\xxxx\xxxx\AppData\Local\Programs\Python\Python36\xxxx\data.py", line 46, in box_data_extract
pd.read_sql_query(query, connection)
File "C:\xxxx\xxxx\AppData\Local\Programs\Python\Python36\lib\site-packages\pandas\io\sql.py", line 332, in read_sql_query
chunksize=chunksize,
File "C:\xxxx\xxxx\AppData\Local\Programs\Python\Python36\lib\site-packages\pandas\io\sql.py", line 1645, in read_query
cursor = self.execute(*args)
File "C:\xxxx\xxxx\AppData\Local\Programs\Python\Python36\lib\site-packages\pandas\io\sql.py", line 1590, in execute
cur = self.con.cursor()
AttributeError: module 'connection' has no attribute 'cursor'
main.py
import connection
import credential
import data
import emailer
import queries
import tables
def main():
# Create connection to box_db file and JDE
#
print("Creating connections")
sqlite_conn = connection.box_db_connect(tables.DB_PATH)
jde_conn = connection.mrap0680_connect(credential.USERNAME, credential.MRAP0680_PASSWORD)
# If new path has been chosen create sqlite db and tables accordingly
#
tables.create_box_table(sqlite_conn)
tables.create_box_staging_table(sqlite_conn)
tables.create_lot_startsite_map_table(sqlite_conn)
# Extract & insert JDE Box Query results into BoxStaging table
#
print("Extracting from JDE")
df = data.box_data_extract(queries.BOX_QUERY, jde_conn) #############LINE CAUSING ERROR
print("Storing in box_db")
data.box_data_insert(df, sqlite_conn)
print("BoxStaging updated")
data.py
# Extract the box data from JDE
#
def box_data_extract(query, connnection):
try:
df = pd.read_sql(query, con=connection)
print("JDE Box Data extracted")
return df
except Exception as e:
print(repr(e))
connection.py
def xxxx_connect(username, password):
# Connect to JDE database
try:
print("Attempting to connect")
conn = cx_Oracle.connect(user=username, password=password, dsn=DSN_TNS)
print("Connection to JDE Successful")
return conn
except Exception as e:
print(repr(e))
I am able to extract the data if running manually.
Please help. Thanks.
I found the error! The issue was in data.py. In the parameter list of data_box_extract, connection is spelled as "connnection". Inside the function, "connection" was being used so a cursor couldn't be instantiated. Not sure why it didn't throw an error about "connection" not being instantiated. Oh well, I'm writing the program in IDLE, maybe it's time to switch to an IDE that will catch those mistakes...
Thanks to all who viewed!
I encoded a value from input file and inserted into Sqlite DB
cur.execute('''INSERT INTO Locations (address, geodata)
VALUES ( ?, ? )''', (memoryview(address.encode()), memoryview(data.encode()) ) )
Now I'm trying to decode it but I'm getting
Traceback (most recent call last):
File "return.py", line 9, in
print(c.decode('utf-8'))
AttributeError: 'tuple' object has no attribute 'decode'
My code looks like this:
import sqlite3
conn = sqlite3.connect('geodata.sqlite')
cur = conn.cursor()
cur.execute('SELECT address FROM Locations')
for c in cur:
print(c.decode('utf-8'))
Regardless of how many columns are selected, rows are returned as tuples. You would get the first element of the tuple the usual way.
I am unable to create a database file using python. I am facing this issue only in windows. On my Mac machine i was able to get it working. Here is a test code i tried -
import os, sys, shutil, glob, pandas, sqlite3
db_path = 'E:\\Archive.db'
conn = sqlite3.connect(db_path)
Here are other versions of variable db_path i have tried
db_path = 'E:\Archive.db'
db_path = 'E:/Archive.db'
db_path = 'E://Archive.db'
But i always get following error -
Traceback (most recent call last):
File "test.py", line 4, in <module>
conn = sqlite3.connect(db_path)
sqlite3.OperationalError: unable to open database file
I do have write permissions on E:
I was able to create csv files using python script. Not sure why its stuck with database. It should create the database in E:
Following example taken from here works for me. Try this out. If this doesn't work, try to create a file in your documents folder by changing the path
import sqlite3
from sqlite3 import Error
def create_connection(db_file):
""" create a database connection to a SQLite database """
conn = None
try:
conn = sqlite3.connect(db_file)
print(sqlite3.version)
except Error as e:
print(e)
finally:
if conn:
conn.close()
if __name__ == '__main__':
create_connection(r"E:\Archive.db")
I've installed DataStax Community Edition, and added DataStax ODBC connector. Now I try to access the database via pyodbc:
import pyodbc
connection = pyodbc.connect('Driver=DataStax Cassandra ODBC Driver;Host=127.0.0.1',
autocommit = True)
cursor = connection.cursor()
cursor.execute('CREATE TABLE Test (id INT PRIMARY KEY)')
cursor.execute('INSERT INTO Test (id) VALUES (1)')
for row in cursor.execute('SELECT * FROM Test'):
print row
It works fine and returns
>>> (1, )
However when I try
cursor.execute('INSERT INTO Test (id) VALUES (:id)', {'id': 2})
I get
>>> Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "test.py", line 11, in <module>
cursor.execute('INSERT INTO Test (id) VALUES (:id)', {'id': 2})
pyodbc.ProgrammingError: ('The SQL contains 0 parameter markers, but 1 parameters were supplied', 'HY000')
Alternatives do neither work:
cursor.execute('INSERT INTO Test (id) VALUES (:1)', (2))
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "test.py", line 11, in <module>
cursor.execute('INSERT INTO Test (id) VALUES (?)', (2))
pyodbc.ProgrammingError: ('The SQL contains 0 parameter markers, but 1 parameters were supplied', 'HY000')
and
cursor.execute('INSERT INTO Test (id) VALUES (?)', (2))
>>> Traceback (most recent call last):
File "<stdin>", line 1, in <module>
pyodbc.Error: ('HY000', "[HY000] [DataStax][CassandraODBC] (15) Error while preparing a query in Cassandra: [33562624] : line 1:31 no viable alternative at input '1' (...Test (id) VALUES (:[1]...) (15) (SQLPrepare)")
My Cassandra version is 2.2.3, ODBC driver is from https://downloads.datastax.com/odbc-cql/1.0.1.1002/
According to pyodbc Documentation your query should be
cursor.execute('INSERT INTO Test (id) VALUES (?)', 2)
More details on pyodbc Insert
As per the comment got a thread which says it is a open bug in pyodbc
BUG