Validation Rules Builder

Business Case

Problem Statement

Construction data quality challenges:

• Inconsistent naming conventions
• Invalid cost codes and WBS
• Missing or malformed data
• Non-compliant BIM elements

Solution

Rule-based validation engine using RegEx and logic rules to ensure data quality across construction systems.

Technical Implementation

python
import re
from typing import Dict, Any, List, Optional, Callable
from dataclasses import dataclass, field
from enum import Enum
from datetime import date


class RuleType(Enum):
    REGEX = "regex"
    RANGE = "range"
    ENUM = "enum"
    CUSTOM = "custom"
    REQUIRED = "required"
    DATE = "date"
    REFERENCE = "reference"


class Severity(Enum):
    ERROR = "error"
    WARNING = "warning"
    INFO = "info"


@dataclass
class ValidationResult:
    field: str
    is_valid: bool
    message: str
    severity: Severity
    value: Any = None


@dataclass
class ValidationRule:
    name: str
    field: str
    rule_type: RuleType
    pattern: str = ""
    min_value: float = None
    max_value: float = None
    allowed_values: List[Any] = field(default_factory=list)
    custom_func: Callable = None
    severity: Severity = Severity.ERROR
    message: str = ""
    enabled: bool = True


class ValidationRulesBuilder:
    """Build and execute validation rules for construction data."""

    # Pre-defined patterns for construction data
    PATTERNS = {
        'wbs_code': r'^[0-9]{2}\.[0-9]{2}\.[0-9]{2}(\.[0-9]{2})?$',
        'cost_code': r'^[A-Z]{1,3}-[0-9]{3,6}$',
        'activity_id': r'^[A-Z]{1,3}[0-9]{4,6}$',
        'drawing_number': r'^[A-Z]{1,2}-[0-9]{3}-[A-Z0-9]{2,4}$',
        'specification_section': r'^[0-9]{2}\s?[0-9]{2}\s?[0-9]{2}(\.[0-9]{2})?$',
        'level_name': r'^(Level|L|FL)\s?[-_]?\s?([0-9]{1,3}|B[0-9]|R|G|M)$',
        'grid_line': r'^[A-Z]\.?[0-9]?$|^[0-9]{1,2}\.?[A-Z]?$',
        'revision': r'^[A-Z]$|^[0-9]{1,2}$|^Rev\.?\s?[A-Z0-9]+$',
        'date_iso': r'^\d{4}-\d{2}-\d{2}$',
        'email': r'^[\w\.-]+@[\w\.-]+\.\w+$',
        'phone': r'^\+?[0-9]{1,3}[-.\s]?[0-9]{3,4}[-.\s]?[0-9]{4}$',
    }

    def __init__(self):
        self.rules: List[ValidationRule] = []
        self.custom_patterns: Dict[str, str] = {}

    def add_regex_rule(self,
                       name: str,
                       field: str,
                       pattern: str,
                       message: str = "",
                       severity: Severity = Severity.ERROR) -> 'ValidationRulesBuilder':
        """Add regex validation rule."""

        self.rules.append(ValidationRule(
            name=name,
            field=field,
            rule_type=RuleType.REGEX,
            pattern=pattern,
            message=message or f"Field '{field}' does not match pattern",
            severity=severity
        ))
        return self

    def add_range_rule(self,
                       name: str,
                       field: str,
                       min_value: float = None,
                       max_value: float = None,
                       message: str = "",
                       severity: Severity = Severity.ERROR) -> 'ValidationRulesBuilder':
        """Add numeric range validation rule."""

        self.rules.append(ValidationRule(
            name=name,
            field=field,
            rule_type=RuleType.RANGE,
            min_value=min_value,
            max_value=max_value,
            message=message or f"Field '{field}' out of range [{min_value}, {max_value}]",
            severity=severity
        ))
        return self

    def add_enum_rule(self,
                      name: str,
                      field: str,
                      allowed_values: List[Any],
                      message: str = "",
                      severity: Severity = Severity.ERROR) -> 'ValidationRulesBuilder':
        """Add enumeration validation rule."""

        self.rules.append(ValidationRule(
            name=name,
            field=field,
            rule_type=RuleType.ENUM,
            allowed_values=allowed_values,
            message=message or f"Field '{field}' must be one of: {allowed_values}",
            severity=severity
        ))
        return self

    def add_required_rule(self,
                          name: str,
                          field: str,
                          message: str = "",
                          severity: Severity = Severity.ERROR) -> 'ValidationRulesBuilder':
        """Add required field validation rule."""

        self.rules.append(ValidationRule(
            name=name,
            field=field,
            rule_type=RuleType.REQUIRED,
            message=message or f"Field '{field}' is required",
            severity=severity
        ))
        return self

    def add_custom_rule(self,
                        name: str,
                        field: str,
                        func: Callable[[Any], bool],
                        message: str = "",
                        severity: Severity = Severity.ERROR) -> 'ValidationRulesBuilder':
        """Add custom validation function."""

        self.rules.append(ValidationRule(
            name=name,
            field=field,
            rule_type=RuleType.CUSTOM,
            custom_func=func,
            message=message or f"Field '{field}' failed custom validation",
            severity=severity
        ))
        return self

    def add_pattern(self, name: str, pattern: str):
        """Add custom pattern for reuse."""
        self.custom_patterns[name] = pattern

    def use_pattern(self,
                    rule_name: str,
                    field: str,
                    pattern_name: str,
                    message: str = "",
                    severity: Severity = Severity.ERROR) -> 'ValidationRulesBuilder':
        """Use pre-defined or custom pattern."""

        pattern = self.custom_patterns.get(pattern_name) or self.PATTERNS.get(pattern_name)
        if not pattern:
            raise ValueError(f"Pattern '{pattern_name}' not found")

        return self.add_regex_rule(rule_name, field, pattern, message, severity)

    def validate_record(self, record: Dict[str, Any]) -> List[ValidationResult]:
        """Validate a single record against all rules."""

        results = []

        for rule in self.rules:
            if not rule.enabled:
                continue

            value = record.get(rule.field)
            result = self._apply_rule(rule, value)
            results.append(result)

        return results

    def validate_records(self, records: List[Dict[str, Any]]) -> Dict[str, Any]:
        """Validate multiple records and return summary."""

        all_results = []
        error_count = 0
        warning_count = 0

        for i, record in enumerate(records):
            record_results = self.validate_record(record)
            for result in record_results:
                if not result.is_valid:
                    result_dict = {
                        'record_index': i,
                        'field': result.field,
                        'message': result.message,
                        'severity': result.severity.value,
                        'value': result.value
                    }
                    all_results.append(result_dict)

                    if result.severity == Severity.ERROR:
                        error_count += 1
                    elif result.severity == Severity.WARNING:
                        warning_count += 1

        return {
            'total_records': len(records),
            'valid_records': len(records) - len(set(r['record_index'] for r in all_results if r['severity'] == 'error')),
            'error_count': error_count,
            'warning_count': warning_count,
            'issues': all_results
        }

    def _apply_rule(self, rule: ValidationRule, value: Any) -> ValidationResult:
        """Apply single validation rule."""

        if rule.rule_type == RuleType.REQUIRED:
            is_valid = value is not None and value != "" and value != []
            return ValidationResult(
                field=rule.field,
                is_valid=is_valid,
                message="" if is_valid else rule.message,
                severity=rule.severity,
                value=value
            )

        # Skip other validations if value is None/empty
        if value is None or value == "":
            return ValidationResult(
                field=rule.field,
                is_valid=True,
                message="",
                severity=rule.severity,
                value=value
            )

        if rule.rule_type == RuleType.REGEX:
            is_valid = bool(re.match(rule.pattern, str(value)))

        elif rule.rule_type == RuleType.RANGE:
            try:
                num_value = float(value)
                is_valid = True
                if rule.min_value is not None and num_value < rule.min_value:
                    is_valid = False
                if rule.max_value is not None and num_value > rule.max_value:
                    is_valid = False
            except (ValueError, TypeError):
                is_valid = False

        elif rule.rule_type == RuleType.ENUM:
            is_valid = value in rule.allowed_values

        elif rule.rule_type == RuleType.CUSTOM:
            try:
                is_valid = rule.custom_func(value)
            except Exception:
                is_valid = False

        else:
            is_valid = True

        return ValidationResult(
            field=rule.field,
            is_valid=is_valid,
            message="" if is_valid else rule.message,
            severity=rule.severity,
            value=value
        )

    def get_rules_summary(self) -> List[Dict]:
        """Get summary of all rules."""

        return [{
            'name': r.name,
            'field': r.field,
            'type': r.rule_type.value,
            'severity': r.severity.value,
            'enabled': r.enabled
        } for r in self.rules]


# Construction-specific validators
class ConstructionValidators:
    """Pre-built validators for construction data."""

    @staticmethod
    def wbs_validator() -> ValidationRulesBuilder:
        """Validator for WBS codes."""

        return (ValidationRulesBuilder()
            .add_required_rule("wbs_required", "wbs_code")
            .use_pattern("wbs_format", "wbs_code", "wbs_code", "Invalid WBS format (expected: XX.XX.XX)")
        )

    @staticmethod
    def cost_item_validator() -> ValidationRulesBuilder:
        """Validator for cost items."""

        return (ValidationRulesBuilder()
            .add_required_rule("code_required", "cost_code")
            .add_required_rule("desc_required", "description")
            .use_pattern("code_format", "cost_code", "cost_code")
            .add_range_rule("quantity_positive", "quantity", min_value=0)
            .add_range_rule("unit_cost_positive", "unit_cost", min_value=0)
            .add_enum_rule("unit_valid", "unit", ["EA", "LF", "SF", "CY", "TON", "HR", "LS"])
        )

    @staticmethod
    def schedule_activity_validator() -> ValidationRulesBuilder:
        """Validator for schedule activities."""

        def dates_valid(record):
            start = record.get('start_date')
            end = record.get('end_date')
            if start and end:
                return start <= end
            return True

        return (ValidationRulesBuilder()
            .add_required_rule("id_required", "activity_id")
            .add_required_rule("name_required", "activity_name")
            .use_pattern("id_format", "activity_id", "activity_id")
            .add_range_rule("duration_positive", "duration", min_value=0)
            .add_range_rule("progress_range", "percent_complete", min_value=0, max_value=100)
        )

    @staticmethod
    def bim_element_validator() -> ValidationRulesBuilder:
        """Validator for BIM elements."""

        return (ValidationRulesBuilder()
            .add_required_rule("guid_required", "element_guid")
            .add_required_rule("type_required", "element_type")
            .add_required_rule("level_required", "level")
            .use_pattern("level_format", "level", "level_name", severity=Severity.WARNING)
            .add_enum_rule("status_valid", "status",
                          ["New", "Existing", "Demolished", "Temporary"])
        )

Quick Start

python
# Create validator
validator = ValidationRulesBuilder()

# Add rules
validator.add_required_rule("id_required", "item_id")
validator.use_pattern("wbs_valid", "wbs_code", "wbs_code")
validator.add_range_rule("cost_range", "total_cost", min_value=0, max_value=10000000)
validator.add_enum_rule("status_valid", "status", ["Active", "Completed", "Cancelled"])

# Validate records
records = [
    {"item_id": "001", "wbs_code": "01.02.03", "total_cost": 50000, "status": "Active"},
    {"item_id": "", "wbs_code": "invalid", "total_cost": -100, "status": "Unknown"}
]

results = validator.validate_records(records)
print(f"Valid: {results['valid_records']}/{results['total_records']}")
print(f"Errors: {results['error_count']}, Warnings: {results['warning_count']}")

Common Use Cases

1. Cost Data Validation

python
cost_validator = ConstructionValidators.cost_item_validator()
results = cost_validator.validate_records(cost_items)

2. Schedule Validation

python
schedule_validator = ConstructionValidators.schedule_activity_validator()
results = schedule_validator.validate_records(activities)

3. BIM Element Validation

python
bim_validator = ConstructionValidators.bim_element_validator()
results = bim_validator.validate_records(elements)

Resources

• DDC Book: Chapter 2.6 - Data Quality Requirements
• Website: https://datadrivenconstruction.io