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Bulk Copy Handles Decimal Inconsistently Compared with Normal Queries #457
Description
Describe the bug
Trying to insert into a Decimal column with the new bulk_copy can throw an exception regarding mismatched decimal scale, whereas a normal insert will succeed and automatically deal with the issue. I would like to see bulk_copy work similarly and seamlessly.
To reproduce
import mssql_python
from decimal import Decimal
conn = mssql_python.connect([conn string], autocommit=True)
cur = conn.cursor()
cur.execute('create table dectest (d decimal(10, 2));')
# This next line works fine
cur.execute('insert into dectest values (?)', Decimal('123.456'))
# This line fails with the below exception
cur.bulkcopy('dectest', (Decimal('123.456'),))Exception message
ValueError: Input decimal scale 3 exceeds target scale 2
Expected behavior
The bulkcopy should succeed and the value should be automatically rounded as it is in the insert.
Activity
github-actions commentedon Feb 27, 2026
Hi Adam Machanic (@amachanic), thank you for opening this issue!
Our team will review it shortly. We aim to triage all new issues within 24-48 hours and get back to you.
If you have additional information to share, please feel free to update the issue.
Thank you for your patience!
saurabh500 commentedon Feb 28, 2026
Thanks. We were conservative in conversions in bulkcopy for Decimal. The feedback makes sense. We can alleviate this restriction.
amachanic commentedon Aug 7, 2026
Any updates here? Just hit this again today and had to work around. Kind of annoying. Would definitely appreciate a fix!