Changing a field value.

[Maneke]

Hello,

I'm trying to make my first filemaker app. It's a simple app with an order table, and a products table with a relation between the two tables.

I made a layout with a portal that displays many fields as Order Nr, Date, Name and in the portal price quantity total etc..

If I change for example the price of a product in the portal area it changes the price in the products table. How is it possible to change a field value without changing the value in the origin table ?

I hope my question is clear un understandable.

[comment]

The relationship between Orders and Products is many-to-many: one order can have many ordered products, and one product can be ordered in many orders. The standard solution for a many-to-many relationship is to add a join table between the two "main" tables. Typically, for orders and invoices, the table is named LineItems and it contains a record for each join of a product to an order/invoice. Also typically, there will be a Price field in the LineItems table that looks up (i.e. copies) the price of a product from the related record in Products. This way you can change the looked up value without affecting the "list price" in Products, as well as change the price of a product without affecting past orders. 

See also: 
https://help.claris.com/en/pro-help/content/many-to-many-relationships.html
https://help.claris.com/en/pro-help/content/lookups.html

The old demo file found here can also be helpful: 
https://fmforums.com/topic/63425-auto-fill-one-field-with-text-from-two-fields/?do=findComment&comment=300150&_rid=72594

Edited April 20, 2022 by comment

[Maneke]

I did what you have explained and it works great.

Thank you