Validation rule
A validation rule is a condition or constraint that determines whether data, a state, or an operation satisfies specified requirements.
Pro Angular 16
A validation rule is a condition that input data must satisfy to be considered valid.
- How it is used
- Uses validation rules to reject erroneous or deliberately poor input in Angular web forms.
- How deep it goes
- Explains built-in attributes, form integration, state classes, and messages; defers custom validation rules.
- Examples
- Demonstrates product-name validation using required, minlength, pattern, CSS classes, and conditional error messages.
- What you can do after
- Apply validation through Angular template attributes and display feedback from control state and errors.
Grokking Simplicity
A rule that specifies behavior or constraints within the problem domain modeled by software.
- How it is used
- Separates domain behavior from interface actions and technical interaction code to improve testing, reuse, and maintenance.
- How deep it goes
- Defines domain-language boundaries and demonstrates extraction into calculations, while deferring fuller layer design to later treatment.
- Examples
- Uses free shipping, tax calculation, shopping carts, DOM updates, database fallback, and web-request retries as contrasting examples.
- What you can do after
- Diagnose/debug with it by locating domain calculations, separating them from actions, and identifying misplaced infrastructure logic.
Starting Data Analytics with Generative AI and Python
A validation rule is a defined condition that data must satisfy to be considered acceptable.
- How it is used
- Sets acceptable conditions for checking data quality before and during analysis.
- How deep it goes
- Defines upfront expectations, checks types and cross-table consistency, then revises rules after exploratory analysis.
- Examples
- Uses expected ranges, distribution deviations, data-type checks, and missing foreign-key relationships between order and payment tables.
- What you can do after
- Apply it via dataframe checks to flag unexpected values, investigate anomalies, and correct or handle violations.
Read how Starting Data Analytics with Generative AI and Python explains validation rule →
Spring in Action, Sixth Edition
A validation rule is a constraint that determines whether submitted data satisfies a required condition.
- How it is used
- Prevents invalid Taco and order submissions in Spring MVC forms.
- How deep it goes
- Defines annotations, controller integration, and error rendering but stops short of explaining validator internals.
- Examples
- Uses Taco names, ingredient lists, delivery addresses, credit cards, expiration dates, and CVVs.
- What you can do after
- Build it from scratch using validation annotations, Spring’s starter, controller validation, and Thymeleaf error messages.
Read how Spring in Action, Sixth Edition explains validation rule →
Architecture Modernization: Socio-technical alignment of software, strategy, and structure
A business rule is a constraint, policy, or decision criterion that governs behavior in a business domain.
- How it is used
- Uses explicit business rules to align domain understanding with architectural boundaries and team responsibilities.
- How deep it goes
- Captures rules through a short group exercise and collective canvas review rather than detailing implementation mechanics.
- Examples
- Uses discounts and marketing dependencies, a bounded context canvas, and a top-five-rules group exercise.
- What you can do after
- Practice/perform a collaborative exercise that surfaces important rules, misalignment, and boundary trade-offs.
Related concepts
- validationused by · The process of checking data, behavior, systems, models, or results against defined criteria to assess their correctness, suitability, or acceptability.
- ownershipconfigured by · Ownership is a programming-language model that assigns responsibility for controlling a value or resource, including its lifetime and eventual cleanup.
- preconditioncontrasts with · A precondition is a condition or requirement that must be satisfied before an operation, process, or action can proceed correctly.
- DOM updatecontrasts with · A modification to the Document Object Model that changes a document's represented content, structure, or presentation.
- rulekind of · A rule is an explicitly specified condition, procedure, or directive that governs behavior, decisions, or outcomes in a defined domain.
- RequiredAttributeconfigured by · RequiredAttribute is a .NET data-annotation validation attribute that requires an annotated property or field to have a supplied, non-null value.
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