ER diagram template

    Last updated November 3, 2026

    Four entities in a row: Customer, Order, Line item, and Product. The arrows mean a customer places an order, an order has line items, and a line item refers to a product. This is a flowchart of the entities, not a Chen notation file. FlowSimp is completely free to use — no sign-up required.

    Use this template

    What does this template look like?

    Ready to draw?

    No signup. Opens instantly in your browser.

    Open this template

    When should you use it?

    Use it to agree the nouns before you design a table. FlowSimp does not import Mermaid ER diagrams.

    Flowchart symbols · Order fulfillment data-flow template

    What does each step mean?

    1. Customer is the person. Order is one purchase by that person.
    2. Line item is one row on the order. Product is the catalog entry that row points at.
    3. Add a rectangle for Payment or Address if those are separate entities in your system.
    4. Write the cardinality in the label if you need it, such as Order has many line items.