Rules and validation

Declare a condition

Rules express conditions on values, relations or Query results. The Model uses them for validation, Action availability or transitions. Views present the decision without becoming a second business authority.

Condition	Expected values	Purpose
Presence	Field reference	Check required information
Comparison	Field, admitted operator and typed value	Compare an amount or status
Membership	Field and admitted values	Accept several states
Relation	Type, direction and cardinality	Require a linked client
Query	Declared Query and admitted parameters	Check a collection or aggregate
Combination	Bounded boolean expressions	Combine conditions

Useful messages

A failed rule explains what is missing and where to correct it. “Select a client before finalizing” guides the user. Contract names or technical errors do not replace that message.

Example

Finalizing a quote requires a linked client, positive amount and approval. The record can show missing conditions, but the service checks again at confirmation. A disabled button is not an authorization control.

Expression trees are declarative and bounded. Their reference describes admitted variants; rules do not execute JavaScript or SQL supplied by a view.

Applied examples : Check before confirming

One rule requires a company; another rejects a zero or negative amount.

Configuration

Fragment placed in rules[]. Properties and accepted values.

{
  "contract": "WorkspaceRule@1",
  "key": "company-required",
  "label": "Company provided",
  "expression": {
    "kind": "present",
    "field": {
      "definitionPath": "workspace/clients/surface/client",
      "fieldKey": "company"
    }
  }
}

Variation and connection

Fragment placed in rules[]. Properties and accepted values.

{
  "contract": "WorkspaceRule@1",
  "key": "positive-amount",
  "label": "Positive amount",
  "expression": {
    "kind": "compare",
    "field": {
      "definitionPath": "workspace/quotes/surface/quote",
      "fieldKey": "amount"
    },
    "operator": "gt",
    "value": 0
  }
}

UI layout example

The illustrative layout below places this configuration in the Clients/Quotes app. Insert each fragment at the stated location, with Field, Query and Action references matching the Model declarations.

1. Company *
2. Status *
3. Notes
4. Create client

SurfaceClients / North StudioExample

Rules and validationCheck before confirming

Clients

New client

Company *North Studio

Status *Prospect ⌄

Add notes to the record after creation.

CancelCreate client