Validity Checks

Validity checks in Alation Data Quality are used to detect invalid or unexpected values in datasets. These metrics help ensure data conforms to expected formats, ranges, patterns, and business rules by validating individual column values against predefined criteria.

These checks are applied at the column level to identify non-conforming data and is essential for data type validation, format verification, and business rule compliance. The checks returns Pass or Fail status based on whether values meet validation criteria.

Follow these best practices for validity checks:

• For zero tolerance, use = 0 for critical fields requiring 100% validity.

• For tolerance-based, use <= 5% for fields where some invalid data is acceptable.

• For large datasets, prefer percentage-based thresholds over counts.

• Optimize complex patterns for large datasets.

• Test regex patterns on sample data before production use to avoid regex errors.

• Use built-in formats when possible instead of custom regex.

• Consider data volume when setting thresholds.

• Start with common validation patterns before creating custom rules.

• Allow flexibility for international formats (e.g. phone numbers or addresses).

• Update validation rules as business requirements evolve.

• Ensure column data type supports chosen validation. This avoids format mismatches.

• Review and adjust validation rules based on real data patterns to avoid false positives.

Available Metrics

Metric	Purpose	Returns	Best Used For
invalid_count	Count absolute number of invalid values	Integer	Small datasets, zero-tolerance scenarios
invalid_percent	Calculate percentage of invalid values	Percentage	Large datasets, tolerance-based validation

Metric List

Metric	Description	Supported Data Types	Column Configuration Keys
invalid_count	The number of rows in a column that contain values that are not valid	number, text, time	invalid format, invalid values, valid format, valid length, valid max, valid max length, valid min, valid min length, valid values
invalid_count (text only)	Text-specific invalid count with regex support	text	invalid regex, valid regex
invalid_percent	The percentage of rows in a column, relative to the total row count, that contain values that are not valid	number, text, time	invalid format, invalid values, valid format, valid length, valid max, valid max length, valid min, valid min length, valid values
invalid_percent (text only)	Text-specific invalid percentage with regex support	text	invalid regex, valid regex

Configuration Keys

Configuration Key	Description	Expected Value Type
invalid format	Defines the format of a value that Alation ought to register as invalid. Only works with columns that contain data type TEXT.	Format name from valid formats list
invalid regex	Specifies a regular expression to define your own custom invalid values.	regex, no forward slash delimiters
invalid values	Specifies the values that Alation ought to consider invalid.	values in a list
valid format	Defines the format of a value that Alation ought to register as valid. Only works with columns that contain data type TEXT.	Format name from valid formats list
valid length	Specifies a valid length for a string. Works with columns that contain data type TEXT, and also with INTEGER on most databases, where implicit casting from string to integer is supported.	integer
valid max	Specifies a maximum numerical value for valid values.	integer or float
valid max length	Specifies a valid maximum length for a string. Only works with columns that contain data type TEXT.	integer
valid min	Specifies a minimum numerical value for valid values.	integer or float
valid min length	Specifies a valid minimum length for a string. Only works with columns that contain data type TEXT.	integer
valid regex	Specifies a regular expression to define your own custom valid values.	regex, no forward slash delimiters
valid values	Specifies the values that Alation ought to consider valid.	values in a list

Valid formats

Valid formats apply only to columns using data type TEXT, not DATE or NUMBER.

Format Name	Description	Example
credit card number	Four four-digit numbers separated by spaces, dashes, or sixteen-digit number	1234 5678 9012 3456, 1234-5678-9012-3456
date eu	European date format (validates date only, not time)	dd/mm/yyyy
date inverse	Inverse date format (validates date only, not time)	yyyy/mm/dd
date iso 8601	ISO 8601 date and/or time format	2021-04-28T09:00:00+02:00
date us	US date format (validates date only, not time)	mm/dd/yyyy
decimal	Number uses a , or . as a decimal indicator	123.45, 123,45
decimal comma	Number uses , as decimal indicator	123,45
decimal point	Number uses . as decimal indicator	123.45
email	Standard email address format	user@example.com
integer	Whole number	123
ip address	IPv4 address format	192.168.1.1
ipv4 address	IPv4 address format	192.168.1.1
ipv6 address	IPv6 address format	2001:0db8:85a3:0000:0000:8a2e:0370:7334
money	Money pattern with currency symbol + decimal + currency abbreviation	$123.45 USD
money comma	Money pattern with currency symbol + decimal comma + currency abbreviation	€123,45 EUR
money point	Money pattern with currency symbol + decimal point + currency abbreviation	$123.45 USD
negative decimal	Negative number with decimal indicator	-123.45, -123,45
negative decimal comma	Negative number with comma as decimal indicator	-123,45
negative decimal point	Negative number with point as decimal indicator	-123.45
negative integer	Negative whole number	-123
negative percentage	Negative percentage	-50%
negative percentage comma	Negative percentage with comma decimal indicator	-50,5%
negative percentage point	Negative percentage with point decimal indicator	-50.5%
percentage	Percentage value	50%
percentage comma	Percentage with comma decimal indicator	50,5%
percentage point	Percentage with point decimal indicator	50.5%
phone number	Various phone number formats	+12 123 123 1234, 123 123 1234, +1 123-123-1234, 555-2368
positive decimal	Positive number with decimal indicator	123.45, 123,45
positive decimal comma	Positive number with comma as decimal indicator	123,45
positive decimal point	Positive number with point as decimal indicator	123.45
positive integer	Positive whole number	123
positive percentage	Positive percentage	50%
positive percentage comma	Positive percentage with comma decimal indicator	50,5%
positive percentage point	Positive percentage with point decimal indicator	50.5%
time 12h	12-hour clock format with seconds	hh:mm:ss AM/PM
time 12h nosec	12-hour clock format without seconds	hh:mm AM/PM
time 24h	24-hour clock format with seconds	hh:mm:ss
time 24h nosec	24-hour clock format without seconds	hh:mm
timestamp 12h	12-hour clock timestamp	hh:mm:ss AM/PM
timestamp 24h	24-hour clock timestamp	hh:mm:ss
uuid	Universally unique identifier	550e8400-e29b-41d4-a716-446655440000

Common Use Cases

Scenario	Configuration Approach	Example
Email Validation	Use built-in email format	valid format: email
Phone Numbers	Use phone format or custom regex	valid format: phone number
Status Fields	Define allowed values list	valid values: PENDING, APPROVED, or REJECTED
ID Formats	Use regex patterns	valid regex: ^[A-Z]{2}-[0-9]{6}$
Numerical Ranges	Set min/max boundaries	valid min: 1, valid max: 100
Text Length	Control string length	valid min length: 5, valid max length: 50

Common Validity Check Types

Format-Based Validation

Use predefined formats for common data patterns:

invalid_count(email_address) = 0:
valid format: email

Value-Based Validation

Specify allowed/disallowed values.

invalid_count(status) = 0:
valid values: [ACTIVE, INACTIVE, PENDING]

Pattern-Based Validation

Use regex for custom patterns.

invalid_count(product_code) = 0:
valid regex: '^PROD-[0-9]{4}$'

Range-Based Validation

Set numerical or length boundaries.

invalid_count(age) = 0:
valid min: 0
valid max: 120

Integration with Other Checks

• Combine with Completeness Checks: This ensures fields are both present and valid.

  Ensure emails exist and are properly formatted, valid format: email: missing_count(email) = 0 and invalid_count(email) = 0:

• Layer with Uniqueness Checks: This validates format and uniqueness.

  Customer IDs must be unique and follow pattern, valid regex: ^CUST-[0-9]{8}$: duplicate_count(customer_id) = 0 and invalid_count(customer_id) = 0: