Constraints & Validation

Constraints enforce data quality at the schema level. When a user enters data that violates a constraint, they see a clear error message before the data is saved.

Column Constraints

Column constraints validate a single field's value. Select a column in the properties panel to manage its constraints.

Available Types

Constraint	Applies To	Description
Not Blank	Text	Value cannot be empty or whitespace
Min	Numbers	Value must be at least this number
Max	Numbers	Value must be at most this number
Min Length	Text	Minimum number of characters
Max Length	Text	Maximum number of characters
Pattern	Text	Must match a regular expression
Email	Text	Must be a valid email address
URL	Text	Must be a valid URL
Positive	Numbers	Must be greater than zero
Negative	Numbers	Must be less than zero
Positive or Zero	Numbers	Must be zero or greater
Negative or Zero	Numbers	Must be zero or less
Past	Dates	Must be in the past
Future	Dates	Must be in the future

Adding a Column Constraint

1. Select a column in the properties panel
2. Scroll to the Constraints section
3. Choose a constraint type from the dropdown
4. Configure the value (if required) and error message
5. Click Add

Custom Error Messages

Each constraint has an error message shown to users when validation fails. Write clear, actionable messages like:

• "Email address is required" (not "Validation error")
• "Price must be greater than 0" (not "Invalid value")

Entity Constraints

Entity constraints validate relationships between multiple columns. Manage them in the View tab of the properties panel.

Available Types

Constraint	Description
Unique Composite	Combination of selected fields must be unique across all rows
Field Less Than	First field must be less than second field
Field Less Than or Equal	First field must be less than or equal to second field
Field Greater Than	First field must be greater than second field
Field Greater Than or Equal	First field must be greater than or equal to second field
Fields Not Equal	Two fields must have different values
Conditional Required	Field is required when another field has a value
At Least One Required	At least one of the selected fields must have a value
All or None	All selected fields must have values, or none of them

Example: Date Range Validation

To ensure a "Start Date" is always before an "End Date":

1. Open the View tab in the properties panel
2. Add an entity constraint of type Field Less Than
3. Select "Start Date" as the first field and "End Date" as the second
4. Set the error message to "Start date must be before end date"

Enabling and Disabling

Each constraint has an enabled toggle. Disable a constraint temporarily without deleting it — useful during data migration or bulk imports.

Reordering

Drag constraints to reorder them. Constraints are evaluated in order, and the first violation is shown to the user.