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Alternative to_sql() *method* for mssql+pyodbc
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# Alternative to_sql() *method* for mssql+pyodbc or mssql+pymssql | |
# | |
# adapted from https://pandas.pydata.org/docs/user_guide/io.html#io-sql-method | |
import json | |
import pandas as pd | |
import sqlalchemy as sa | |
def mssql_insert_json(table, conn, keys, data_iter): | |
""" | |
Execute SQL statement inserting data via OPENJSON | |
Parameters | |
---------- | |
table : pandas.io.sql.SQLTable | |
conn : sqlalchemy.engine.Engine or sqlalchemy.engine.Connection | |
keys : list of str | |
Column names | |
data_iter : Iterable that iterates the values to be inserted | |
""" | |
# build dict of {"column_name": "column_type"} | |
col_dict = { | |
str(col.name): "varchar(max)" | |
if str(col.type) == "TEXT" | |
else "nvarchar(max)" | |
if str(col.type) == "NTEXT" | |
else str(col.type) | |
for col in table.table.columns | |
} | |
columns = ", ".join([f"[{k}]" for k in keys]) | |
if table.schema: | |
table_name = f"[{table.schema}].[{table.name}]" | |
else: | |
table_name = f"[{table.name}]" | |
json_data = [dict(zip(keys, row)) for row in data_iter] | |
with_clause = ",\n".join( | |
[ | |
f"{col_name} {col_type} '$.{col_name}'" | |
for col_name, col_type in col_dict.items() | |
] | |
) | |
placeholder = "?" if conn.dialect.paramstyle == "qmark" else "%s" | |
sql = f"""\ | |
INSERT INTO {table_name} ({columns}) | |
SELECT {columns} | |
FROM OPENJSON({placeholder}) | |
WITH | |
( | |
{with_clause} | |
); | |
""" | |
conn.exec_driver_sql(sql, (json.dumps(json_data),)) | |
if __name__ == "__main__": | |
# ============= | |
# USAGE EXAMPLE | |
# ============= | |
# note: fast_executemany=True is not required | |
engine = sa.create_engine("mssql+pyodbc://scott:tiger^5HHH@mssql_199") | |
df = pd.DataFrame([(1, "Alfa"), (2, "Bravo")], columns=["id", "txt"]) | |
df.to_sql( | |
"##tmp", | |
engine, | |
index=False, | |
if_exists="append", | |
method=mssql_insert_json, | |
) | |
# check result | |
with engine.begin() as connection: | |
print(connection.exec_driver_sql("SELECT * FROM ##tmp").all()) | |
# [(1, 'Alfa'), (2, 'Bravo')] |
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