Library Quality Rules

A type: library rule is a predefined, portable check selected with a metric name. Unlike SQL rules, you don't write a query — the CLI compiles the metric into dialect-specific SQL for the selected server, so the same rule works across all backends.

quality:
  - type: library
    metric: nullValues
    mustBe: 0

Each rule combines a metric, optional arguments, and exactly one comparator (mustBe, mustBeBetween, …).

Supported metrics

Metric	Level	Measures	Arguments
rowCount	schema	Number of rows in the table	—
duplicateValues	schema or property	Number of duplicate values	schema-level: properties (list of columns to check together)
nullValues	property	Number of NULL values	—
missingValues	property	Number of missing values (NULL plus the values you treat as missing)	missingValues (list of values counted as missing, e.g. ['', 'N/A'])
invalidValues	property	Number of values not in an allow-list	validValues (list of permitted values)

note

nullValues, missingValues, and invalidValues are only supported at the property level. rowCount is schema level. duplicateValues works at either level.

Examples

Row count (schema level):

schema:
  - name: orders
    quality:
      - type: library
        metric: rowCount
        mustBeGreaterThan: 0

No nulls in a property:

quality:
  - type: library
    metric: nullValues
    mustBe: 0

Missing values — treat empty string and N/A as missing, in addition to NULL:

quality:
  - type: library
    metric: missingValues
    arguments:
      missingValues: [null, '', 'N/A']
    mustBe: 0

Invalid values — the value must be one of an allow-list:

quality:
  - type: library
    metric: invalidValues
    arguments:
      validValues: ['CX-263-DU', 'IK-894-MN', 'ER-399-JY']
    mustBe: 0

Duplicate values across a set of columns (schema level):

schema:
  - name: orders
    quality:
      - type: library
        metric: duplicateValues
        arguments:
          properties: [order_id, line_number]
        mustBe: 0

Comparators

Use exactly one comparator to define the threshold:

Comparator	Passes when the metric…
mustBe	equals the value
mustNotBe	does not equal the value
mustBeGreaterThan / mustBeGreaterOrEqualTo	is above a lower bound
mustBeLessThan / mustBeLessOrEqualTo	is below an upper bound
mustBeBetween / mustNotBeBetween	is inside / outside a [min, max] range

Percentage thresholds

For the count-of-bad-rows metrics (nullValues, missingValues, invalidValues), set unit: percent to compare against a percentage of rows instead of an absolute count:

quality:
  - type: library
    metric: nullValues
    unit: percent
    mustBeLessThan: 1   # fewer than 1% of rows are null

unit: percent is ignored (with a warning) for metrics that are not count-of-bad-rows.