I can successfully query and insert data using sqlalchemy and pandas:
from sqlalchemy import create_engine
import pandas as pd
engine = create_engine('mssql://myserver/mydb?driver=SQL+Server+Native+Client+11.0?trusted_connection=yes')
Read tempy table:
sql_command = """
select top 100 * from tempy
"""
df = pd.read_sql(sql_command, engine)
print df
tempID tempValue
0 1 2
Append new data:
df_append = pd.DataFrame( [[4,6]] , columns=['tempID','tempValue'])
df_append.to_sql(name='tempy', con=engine, if_exists = 'append', index=False)
df = pd.read_sql(sql_command, engine)
print df
tempID tempValue
0 1 2
1 4 6
Try to truncate data:
connection = engine.connect()
connection.execute( '''TRUNCATE TABLE tempy''' )
connection.close()
Read table again, but truncate failed:
df = pd.read_sql(sql_command, engine)
print df
tempID tempValue
0 1 2
1 4 6
I have the same problem with pandas 0.19.2 and sqlalchemy 1.1.5.
As I see autocommit is not forced in engine.execute() when running a TRUNCATE statement. If I force it manually then TRUNCATE works perfectly:
from sqlalchemy.sql import text as sa_text
engine.execute(sa_text('''TRUNCATE TABLE tempy''').execution_options(autocommit=True))
It's fancy that DROP works perfectly without forcing autocommit...
This worked for me:
from sqlalchemy.orm import sessionmaker
Session = sessionmaker(bind=engine)
session = Session()
session.execute('''TRUNCATE TABLE tempy''')
session.commit()
session.close()
Here is a full solution based from the question, using sqlalchemy 1.1.15 on Windows I was receiving errors trying to implement the other solutions:
import sqlalchemy
engine = sqlalchemy.create_engine('mssql://myserver/mydb?driver=SQL+Server+Native+Client+11.0?trusted_connection=yes')
connection = engine.connect()
truncate_query = sqlalchemy.text("TRUNCATE TABLE tempy")
connection.execution_options(autocommit=True).execute(truncate_query)