Stefan Stefan - 1 month ago 27
MySQL Question

How to insert pandas dataframe via mysqldb into database?

I can connect to my local mysql database from python, and I can create, select from, and insert individual rows.

My question is: can I directly instruct mysqldb to take an entire dataframe and insert it into an existing table, or do I need to iterate over the rows?

In either case, what would the python script look like for a very simple table with ID and two data columns, and a matching dataframe?

Answer

Update:

There is now a to_sql method, which is the preferred way to do this, rather than write_frame:

df.to_sql(con=con, name='table_name_for_df', if_exists='replace', flavor='mysql')

Also note: the syntax may change in pandas 0.14...

You can set up the connection with MySQLdb:

from pandas.io import sql
import MySQLdb

con = MySQLdb.connect()  # may need to add some other options to connect

Setting the flavor of write_frame to 'mysql' means you can write to mysql:

sql.write_frame(df, con=con, name='table_name_for_df', 
                if_exists='replace', flavor='mysql')

The argument if_exists tells pandas how to deal if the table already exists:

if_exists: {'fail', 'replace', 'append'}, default 'fail'
     fail: If table exists, do nothing.
     replace: If table exists, drop it, recreate it, and insert data.
     append: If table exists, insert data. Create if does not exist.

Although the write_frame docs currently suggest it only works on sqlite, mysql appears to be supported and in fact there is quite a bit of mysql testing in the codebase.

Comments