Schema Builder for data model design
Key Takeaway
Schema Builder lets you view and build your data model on one canvas. A field you add there is not automatically added to the page layout, so you must edit the page layout.
Schema Builder is a visual tool in Setup. It shows your objects, fields, and relationships on one canvas, and you can create new ones by dragging and dropping. Schema Builder makes it easier to design, understand, and change a data model because you don't have to click from page to page in Setup.
What Schema Builder shows and when it is useful
Schema Builder works like a live diagram of your data model. It shows standard and custom objects with their fields and required fields. It also shows the lookup and master-detail relationships between the objects, so you can see how they connect at a glance.
Schema Builder is useful for designing and understanding complex data models. It also helps when you introduce your customizations to a co-worker or explain how data flows through your system.