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I have a table in MySql DB. I need to update a particular column for all the rows in the table. I need to do this in a single call without deleting the rows, only updating the column values.

I have tried using df.to_sql(if_exists='replace') but this deletes the rows and re-inserts them. Doing so drops the rows from other table which are linked by the foreign key.

merge_df = merge_df[['id', 'deal_name', 'fund', 'deal_value']]
for index, row in merge_df.iterrows():
        ma_deal_obj = MA_Deals.objects.get(id=row['id'])
        ma_deal_obj.deal_value = row['deal_value']
        ma_deal_obj.save()

merge_df has other columns as well. I only need to update the 'deal_value' column for all rows.

One solution I have is by iterating over the dataframe rows and using Django ORM to save the value but this is quite slow for too many rows.

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  • Does this answer your question? How to update multiple rows with single MySQL query in python? Commented Oct 31, 2019 at 17:46
  • 1
    So are you saying you need to execute UPDATE MA_Deals SET deal_value = 'new-value'; Commented Oct 31, 2019 at 17:51
  • @MarlinPierce No, that would make the value of deal_value = 'new-value' for all rows, I need to set different values of deal value for each row. Something like UPDATE MA_Deals SET deal_value = 'new-value1' where id = 1; UPDATE MA_Deals SET deal_value = 'new-value2' where id = 2; UPDATE MA_Deals SET deal_value = 'new-value3' where id = 3; All this but in a single call This is what I was looking for. Commented Jan 3, 2020 at 17:37
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