<@ULVA73B9P> How can I use the sqlalchemy connecto...
# ask-marvin
e
@Marvin How can I use the sqlalchemy connector to insert a pandas dataframe into a database? Here is my code so far:
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with SqlAlchemyConnector.load("fqrs-sqlserver") as connector:
        connector.execute(file_as_string("src/tfs_flows/socials/SQL/create_table.sql"))
        connector.execute("TRUNCATE table dw_temp.dbo.socials_testing")
        
       # Insert dataframe here
m
thought for 84.4 seconds
You can hand the connector’s SQLAlchemy engine or connection to pandas’
to_sql
. Here are two common patterns: Using the engine (simple and works well with pandas):
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from prefect_sqlalchemy import SqlAlchemyConnector

# assume you already have a DataFrame named df

with SqlAlchemyConnector.load("fqrs-sqlserver") as connector:
    connector.execute(file_as_string("src/tfs_flows/socials/SQL/create_table.sql"))
    connector.execute("TRUNCATE TABLE dw_temp.dbo.socials_testing")

    # For SQL Server, fast_executemany can speed up inserts
    engine = connector.get_engine(fast_executemany=True)

    df.to_sql(
        name="socials_testing",
        con=engine,
        schema="dw_temp",
        if_exists="append",
        index=False,
        chunksize=1000,      # tune for your data
        method="multi"       # batches values into multi-row INSERTs
    )
Using a transactional connection:
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from prefect_sqlalchemy import SqlAlchemyConnector

with SqlAlchemyConnector.load("fqrs-sqlserver") as connector:
    connector.execute(file_as_string("src/tfs_flows/socials/SQL/create_table.sql"))
    connector.execute("TRUNCATE TABLE dw_temp.dbo.socials_testing")

    with connector.get_connection() as conn:
        df.to_sql(
            name="socials_testing",
            con=conn,
            schema="dw_temp",
            if_exists="append",
            index=False,
            chunksize=1000,
            method="multi"
        )
Notes: - For SQL Server via pyodbc,
fast_executemany=True
can significantly improve performance. - If you need explicit column types, pass
dtype={...}
with SQLAlchemy types. - If the table already exists (as in your code), keep
if_exists="append"
. Docs for reference: - Prefect SQLAlchemy integration: Prefect SQLAlchemy connector - Pandas `to_sql`: pandas.DataFrame.to_sql If you share your DataFrame shape/size and driver (e.g., mssql+pyodbc), I can suggest optimal
chunksize
and dtype mappings.