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?
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.