I don't have knowledge on SAP ABAP, Can I start to learn SAP FIORI?

SAP Fiori - UI5 Concepts. Advertisements. SAP UI5 is a Java script-based framework that is used to design multi-platform business applications. It supports various data models and views do desktop and mobile applications. SAP UI5 compiles on open Ajax and can be combined with javascript libraries. SAP Fiori apps use OData to display and update data in the back-end server (SAP or Non-SAP). OData (Open Data Protocol) is a standardized protocol for creating and consuming data APIs. OData builds on core protocols like HTTP and commonly accepted methodologies like REST.

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