Python Data Persistence – ORM – Update Data

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Python Data Persistence – ORM – Update Data

Modifying attributes of an object is very easy in SQLAlchemy. First, you have to fetch the desired object, either by the primary key (using the get ( ) method) or by applying the proper filter. All you have to do is assign a new value to its attribute and commit the change.

Following code will fetch an object from the ‘Products’ table whose ProductJD=2 (Product name is TV and price is 40000 as per sample data)

Example

p=q.get(2) 
SELECT "Products"."ProductID" AS "Products_ ProductID", 
"Products".name AS "Products_name", 
"Products".price AS "Products_price" 
FROM "Products" 
WHERE "Products"."ProductID" =? 
2, )

Change the price to 45000 and commit the session.

p.price=45000 
sessionobj.commit( )

SQLAlchemy internally executes the following UPDATE statement:

UPDATE "Products" SET price=? 
WHERE "Products"."ProductID" = ? 
(45000, 2)
 COMMIT