This document describes how to reuse Knowledge Catalog (formerly Dataplex Universal Catalog) data quality rules to define and manage standardized business rules.
Rule reusability lets you share complex or standardized business rule definitions across multiple data quality rules and scans by using rule templates. This document also describes how to set up, create, and manage reusable rule templates, and how to attach data quality rules to catalog entries as metadata aspects.
Use cases
You can use data quality rule reusability for the following scenarios:
- Standardize and share rule definitions: Use custom rule templates to store complex or standardized business rule definitions. This reduces the time and effort required to distribute common definitions by using templatized SQL expressions. For example, a central data governance team can define a standard valid email or valid SSN template that is reused across the entire organization, ensuring consistency and reducing the operational overhead of managing duplicate rules.
- Implement governance-driven quality: Declare data rules as metadata by using Knowledge Catalog aspects on BigQuery table and business glossary term entries. This makes your rules searchable and reusable. For example, when you link a column to a glossary term, it can automatically inherit the validation rules defined for that term, enabling automated governance policies through semantic metadata inheritance.
- Search and discover reusable rules: Find existing rules within your organization through semantic search. This allows data analysts and engineers to discover verified, standardized rule sets (such as "Baseline Financial Constants") and bootstrap data quality for new projects without writing SQL from scratch.
- Eliminate cold-start problems: Leverage system rule templates for frequently used evaluations, such as null checks or range expectations. These built-in templates let you quickly set up data quality monitoring for common scenarios without needing to write custom SQL.
- Enable separation of concerns: Allow central governance teams to author verified rule templates, while engineering teams focus on applying these rules to their data assets without having to write or maintain complex SQL. This clear division of responsibilities improves organizational agility and ensures that data quality standards are consistently applied across the enterprise.
Before you begin
-
Enable the Dataplex API.
Roles required to enable APIs
To enable APIs, you need the Service Usage Admin IAM role (
roles/serviceusage.serviceUsageAdmin), which contains theserviceusage.services.enablepermission. Learn how to grant roles .
Before you use data quality rule reusability, ensure that you have completed the following requirements.
Set up the Dataplex API environment
To use the REST API examples in this document, set up an alias for gcurl
and
configure the ${DATAPLEX_API}
environment variable.
-
Set an alias of
gcurl. This creates a shortcut that includes your authentication token and sets the JSON content-type for API requests:alias gcurl='curl -H "Authorization: Bearer $(gcloud auth print-access-token)" -H "Content-Type: application/json"' -
Set the
DATAPLEX_APIvariable:DATAPLEX_API = "dataplex.googleapis.com/v1/projects/ PROJECT_ID /locations/ LOCATION "
Replace the following:
-
PROJECT_ID: your project ID. -
LOCATION: the location where your scan or resources are located (for example,us-central1).
-
Set up a service account
A service account is mandatory for running data quality scans with reusable rules. Create a service account that has the following Identity and Access Management roles and permissions:
- You must have the
iam.serviceAccounts.actAspermission on the project hosting the service account (typically by using theroles/iam.serviceAccountUserrole). - Grant the Dataplex Service Agent (
service- PROJECT_ID @gcp-sa-dataplex.iam.gserviceaccount.com) for the scan project theiam.serviceAccounts.getAccessTokenpermission on the service account (for example, by using theroles/iam.serviceAccountTokenCreatorrole). - The service account must have the following permissions:
-
bigquery.tables.getDataon the table to be scanned (for example, by usingroles/bigquery.dataViewer). -
bigquery.jobs.insertin the scan project (for example, by usingroles/bigquery.jobUser). -
roles/bigquery.dataEditoron the export dataset (if using export).
-
Required roles and permissions
Ensure you have the following IAM roles for your specific tasks:
- Data scan management: Required data scan roles to manage data scan resources.
- Rule template management: To create or update rule templates, you must
have the necessary permissions to manage entries within the rule template's
entry group or project. Specifically,
roles/dataplex.catalogEditororroles/dataplex.entryOwnergrants these permissions. - Referencing rule templates from rules: You must have
dataplex.entries.getanddataplex.entries.getDatapermissions on the rule template's entry group or project being referenced by a rule. - Attaching data quality rules to BigQuery tables: To attach data
quality rules as Knowledge Catalog metadata, you must have
one of the following:
-
bigquery.tables.updateorroles/bigquery.dataEditoron the table anddataplex.entryGroups.useDataRulesAspecton the@bigqueryentry group in the table location. -
roles/dataplex.catalogEditoron the@bigqueryentry group.
-
- Attaching data quality rules to business glossary terms: To attach data
quality rules as Knowledge Catalog metadata, you must have one of the
following:
-
dataplex.glossaryTerms.updateon the term anddataplex.entryGroups.useDataRulesAspecton the@dataplexentry group. -
roles/dataplex.catalogEditoron the@dataplexentry group.
-
- Creating data quality scans with entry-based rules: You must have one of
the following:
-
bigquery.tables.getandbigquery.tables.getDataon the table. -
dataplex.entries.getanddataplex.entries.getDataon the@bigqueryentry group in the table location.
-
SQL query syntax for rule templates
When you write the SQL logic for a rule template, you must provide a statement that returns invalid rows. If the query returns any rows, the rule fails. For more information, see SqlAssertion .
Follow these guidelines for writing rule template SQL:
- Omit the trailing semicolon from the SQL statement.
- Use
${param(name)}to reference input parameters, for example,${param(min_value)}. - Use
$${...}to escape a literal${...}and prevent it from being replaced as a parameter. - Parameter variables are case-sensitive.
System-supported parameters
You can use the following system-supported parameters in your rule template SQL:
-
${project()}: The project ID of the resource being scanned. -
${dataset()}: The BigQuery dataset ID of the resource being scanned, formatted asPROJECT_ID.DATASET_ID. -
${table()}: The BigQuery table ID of the resource being scanned, formatted asPROJECT_ID.DATASET_ID.TABLE_ID. -
${column()}: The column the rule is evaluated on. An error occurs during rule evaluation if the rule is attached to the table level but references${column()}. -
${data()}: A reference to the data source table and all of its precondition filters like row filters, sampling percentages, and incremental filters defined in the scan specification. For more information, see Data reference parameter .
Example 1: Validate column values are between two values
The following example validates that all values in a column are between a minimum and maximum value:
SELECT
*
FROM
$
{
data
()
}
WHERE
NOT
((
$
{
column
()
}>=
$
{
param
(
min_value
)
}
AND
$
{
column
()
}<=
$
{
param
(
max_value
)
}
)
IS
TRUE
)
Note the following:
- Using
NOT(condition) IS TRUEreturns invalid rows, including rows withNULLvalues in the column. - Using
${data()}limits the scope of rows evaluated to the source table and its filters, such as row filters, sampling percentages, and incremental filters. - Using
${column()}lets you reference the column that the rule using this template is evaluated on.
Example 2: Foreign key validation
The following example verifies that each value in a column exists in a primary key column of another table:
SELECT
t
.
*
FROM
$
{
data
()
}
AS
t
LEFT
JOIN
`${param(reference_table)}`
AS
s
ON
t
.
$
{
column
()
}
=
s
.
`${param(reference_column)}`
WHERE
s
.
`${param(reference_column)}`
IS
NULL
Input parameters for this template are as follows:
-
reference_table: The name of the reference table containing the primary keys. Use the formatPROJECT_ID.DATASET_ID.TABLE_ID. -
reference_column: The name of the primary key column in the reference table.
System rule templates
Knowledge Catalog provides system rule templates that can be used in any
region. Knowledge Catalog manages these templates in the dataplex-templates
project under the rule-library
entry group. An example of
a full resource name is projects/dataplex-templates/locations/global/entryGroups/rule-library/entries/non_null_expectation
.
To view the list of all the available system rule templates, see System rule templates list .
To find the available list of system rule templates, select one of the following options:
Console
-
In the Google Cloud console, go to the Data profiling & qualitypage.
-
Click Rule libraries > System.
-
To see the list of available system rule templates, click rule-library.
When creating a new rule , you can select the system rule templates in the Choose rule typesmenu.
REST
To find the available list of system rule templates, use the entries.list
method:
gcurl "https://dataplex.googleapis.com/v1/projects/dataplex-templates/locations/global/entryGroups/rule-library/entries"
Known differences between system rule templates and built-in rules
The following table describes the differences between system rule templates and built-in rules :
| Feature | System rule templates | Built-in rules |
|---|---|---|
|
Source
|
Reusable templates in the catalog | Built-in in the API |
|
Referencing
|
Can be referenced by catalog entries and scans | Can only be used in scans |
The following list describes additional differences in how metrics are calculated for system rule templates:
- Assertion Row Count metric: This metric is populated for all template reference rules, not just SQL assertion rules.
- Statistic Range Expectation rule template: Rule metrics from evaluation
of rules referencing this template wouldn't contain the
nullCountmetric. Because it is an aggregate rule, theignore nullcapability isn't supported, and rule success is determined by the aggregate statistic being within the defined range. -
Uniqueness Expectation rule template: This template calculates
passedCountdifferently than the built-inUniquenessExpectationrule. The rule template returns all rows for which duplicate values or null rows exist, which can result in fewer passing rows if duplicates are present.For example, if a column contains the values
(a, a, b, b, c, d, e):- Built-in uniqueness rule: Returns 5 passing rows:
(a, b, c, d, e). - Uniqueness rule template: Returns 4 failing rows:
(a, a, b, b). The number of passing rows is 3 (7 total rows minus 4 failed rows):(c, d, e).
- Built-in uniqueness rule: Returns 5 passing rows:
Metadata aspects
This section describes the fields and values for the data-rules
and data-quality-rule-template
aspect types.
data-rules
aspect fields
To define data rules, use the dataplex-types.global.data-rules
aspect. The following table describes the fields for this aspect.
| Field | Type | Description |
|---|---|---|
rules
|
Array | Required. A list of data quality rules. |
rules[].name
|
String | Required. A name for the rule. |
rules[].dimension
|
String | Optional. The data quality dimension for the rule. |
rules[].description
|
String | Optional. The description of the rule. |
rules[].suspended
|
Boolean | Optional. Whether the rule is active or suspended. Default is false
. |
rules[].threshold
|
Double | Optional. The passing threshold for the rule, from 0.0
to 1.0
. Default is 1.0
. |
rules[].type
|
Enum | Required. The type of the rule. The only supported value is TEMPLATE_REFERENCE
. |
rules[].ignore_null
|
Boolean | Optional. If true
, rows with null values in the column are ignored when determining the success criteria. |
rules[].attributes
|
Map | Optional. Custom key-value pairs associated with the rule. |
rules[].templateReference
|
Object | Required. A reference to the rule template. |
rules[].templateReference.name
|
String | Required. The resource name of the rule template . |
rules[].templateReference.values
|
Map | Optional. The parameter names and values for the rule template. |
rules[].templateReference.values[].parameterValue.value
|
String | Required. The value for the parameter. |
The following example shows a data-rules
aspect in a payload.json
file:
{
"aspects"
:
{
"dataplex-types.global.data-rules"
:
{
"data"
:
{
"rules"
:
[
{
"name"
:
"valid-email"
,
"dimension"
:
"VALIDITY"
,
"type"
:
"TEMPLATE_REFERENCE"
,
"templateReference"
:
{
"name"
:
"projects/my-project/locations/us-central1/entryGroups/my-rules/entries/email-check"
,
"values"
:
{
"column_name"
:
{
"value"
:
"email"
}
}
}
}
]
}
}
}
}
data-quality-rule-template
aspect fields
Use the data-quality-rule-template
aspect to define a custom data quality
rule template. The following table describes the fields for the dataplex-types.global.data-quality-rule-template
aspect.
| Field | Type | Description |
|---|---|---|
dimension
|
String | Required. The dimension for the rule template. |
sqlCollection
|
Array | Required. A list of SQL queries for the rule template. |
sqlCollection[].sql.query
|
String | Required. The SQL query that returns invalid rows. |
inputParameters
|
Map | Optional. A map of input parameters for the rule template. |
inputParameters[].parameterDescription.description
|
String | Optional. The description of the input parameter. |
inputParameters[].parameterDescription.defaultValue
|
String | Optional. The default value for the parameter if no value is provided. |
capabilities
|
Array | Optional. A list of template capabilities, such as THRESHOLD
or IGNORE_NULL
. |
The following example displays the structure of a data-quality-rule-template
aspect:
{
"entryType"
:
"projects/dataplex-types/locations/global/entryTypes/data-quality-rule-template"
,
"aspects"
:
{
"dataplex-types.global.data-quality-rule-template"
:
{
"data"
:
{
"dimension"
:
"COMPLETENESS"
,
"sqlCollection"
:
[
{
"query"
:
"SELECT * FROM ${data()} WHERE ${column()} > ${param(p1)}"
}
],
"inputParameters"
:
{
"p1"
:
{
"description"
:
"The parameter description"
}
},
"capabilities"
:
[
"THRESHOLD"
,
"IGNORE_NULL"
]
}
}
}
}
Manage data quality rule templates
This section describes how to create, edit, and delete rule templates.
Create a rule library
To create a rule library, you must create a Knowledge Catalog entry group.
Console
-
In the Google Cloud console, go to the Data profiling & qualitypage.
-
Go to Rule libraries > Custom, and click Create.
-
In the Create rule librarywindow, fill in the following fields:
- Optional: Enter a display name.
- In Rule library ID, enter an ID. For more information, see the resource naming conventions .
- Optional: Enter a description.
- In the Locationmenu, select a location. It can't be changed later.
- Optional: Add labels. Labels are key-value pairs that let you group related objects together or with other Google Cloud resources.
- Click Save.
REST
To create a rule library by using the API, you must create an entry group with
the required label goog-dataplex-entry-group-type: rule_library
:
gcurl -X POST "https:// ${ DATAPLEX_API } /entryGroups?entryGroup_id= RULE_LIBRARY_ID " \ --data @- << EOF { "labels": { "goog-dataplex-entry-group-type": "rule_library" }, "description": " DESCRIPTION " } EOF
Replace the following:
-
RULE_LIBRARY_ID: a unique ID for your rule library. -
DESCRIPTION: an optional description for the rule library.
Terraform
To create a rule library, use the google_dataplex_entry_group
resource:
resource "google_dataplex_entry_group" "rule_library" { project = " PROJECT_ID " location = " LOCATION " entry_group_id = " RULE_LIBRARY_ID " description = " DESCRIPTION " labels = { "goog-dataplex-entry-group-type" = "rule_library" } }
Replace the following:
-
PROJECT_ID: your project ID. -
LOCATION: the location for your rule library (for example,us-central1). -
RULE_LIBRARY_ID: a unique ID for your rule library. -
DESCRIPTION: an optional description for the rule library.
Create a rule template
To create a custom rule template, select one of the following:
Console
-
In the Google Cloud console, go to the Data profiling & qualitypage.
-
Go to Rule libraries > Custom.
-
Click the rule library where you want to add a template, and then click Create.
-
In the Create rule templatewindow, fill in the following fields:
- Optional: Enter a name for the template.
- In Template ID, enter an ID. For more information, see the resource naming conventions .
- Optional: Enter a description.
- In the Dimensionmenu, select a dimension. For more information, see Dimensions .
-
In the SQL queryfield, enter the following example query that validates each column value is between two values:
SELECT * FROM $ { data () } WHERE NOT ( $ { column () }>= $ { param ( min_value ) } AND $ { column () }<= $ { param ( max_value ) } ) IS TRUE -
Optional: To enable the rule referencing this template to specify a threshold for success criteria, select Support threshold.
-
Optional: To allow rules referencing this template to ignore null values in the column for determining success criteria, select Support ignore null.
-
In Input Parameters, click Add input parameter, and then for each parameter used in the SQL query, enter an input name, description, and default value. In the preceding example, the names would be
min_valueandmax_value. -
Click Save.
REST
To create a custom rule template, create an entry of type data-quality-rule-template
:
gcurl -X POST "https:// ${ DATAPLEX_API } /entryGroups/ ENTRY_GROUP_ID /entries?entry_id= TEMPLATE_ID " \ --data @- << EOF { "entryType": "projects/dataplex-types/locations/global/entryTypes/data-quality-rule-template", "entrySource": { "displayName": " DISPLAY_NAME ", "description": " DESCRIPTION " }, "aspects": { "dataplex-types.global.data-quality-rule-template": { "data": { "dimension": "VALIDITY", "sqlCollection": [ { "query": "SELECT t.* FROM ${data()} AS t LEFT JOIN `${param(reference_table)}` AS s ON t.${column()} = s.`${param(reference_column)}` WHERE s.`${param(reference_column)}` IS NULL" } ], "inputParameters": { " PARAMETER_NAME ": { "description": " PARAMETER_DESCRIPTION " } }, "capabilities": ["THRESHOLD"] } } } } EOF
Replace the following:
-
ENTRY_GROUP_ID: the ID of the entry group that stores your rule template. -
TEMPLATE_ID: a unique ID for your rule template. -
DISPLAY_NAME: a display name for the rule template. -
DESCRIPTION: a description of the rule template. -
PARAMETER_NAME: the name of an input parameter used in the SQL query. -
PARAMETER_DESCRIPTION: a description of the input parameter.
Terraform
To create a custom rule template, use the google_dataplex_entry
resource:
resource "google_dataplex_entry" "rule_template" { project = " PROJECT_ID " location = " LOCATION " entry_id = " TEMPLATE_ID " entry_group_id = " ENTRY_GROUP_ID " entry_type = "projects/dataplex-types/locations/global/entryTypes/data-quality-rule-template" entry_source { display_name = " DISPLAY_NAME " description = " DESCRIPTION " } aspects { aspect_key = "dataplex-types.global.data-quality-rule-template" aspect { data = jsonencode ({ dimension = "VALIDITY" sqlCollection = [ { query = "SELECT t.* FROM $${data()} AS t LEFT JOIN `$${param(reference_table)}` AS s ON t.$${column()} = s.`$${param(reference_column)}` WHERE s.`$${param(reference_column)}` IS NULL" } ] inputParameters = { " PARAMETER_NAME " = { description = " PARAMETER_DESCRIPTION " } } capabilities = [ "THRESHOLD" ] }) } } }
Replace the following:
-
PROJECT_ID: your project ID. -
LOCATION: the location for your rule template (for example,us-central1). -
ENTRY_GROUP_ID: the ID of the entry group that stores your rule template. -
TEMPLATE_ID: a unique ID for your rule template. -
DISPLAY_NAME: a display name for the rule template. -
DESCRIPTION: a description of the rule template. -
PARAMETER_NAME: the name of an input parameter used in the SQL query. -
PARAMETER_DESCRIPTION: a description of the input parameter.
Update a rule template
To update an existing rule template, select one of the following options:
Console
-
In the Google Cloud console, go to the Data profiling & qualitypage.
-
Go to Rule libraries > Custom.
-
Click the rule library that contains the template you want to update.
-
In the Rule templateslist, click the template that you want to update.
-
On the rule template details page, click Edit.
-
Update the fields, and then click Save.
REST
To update a custom rule template, patch the entry or specific aspect:
gcurl -X PATCH "https:// ${ DATAPLEX_API } /entryGroups/ ENTRY_GROUP_ID /entries/ TEMPLATE_ID ?updateMask=aspects" \ --data @- << EOF { "aspects": { "dataplex-types.global.data-quality-rule-template": { "data": { "dimension": "VALIDITY", "sqlCollection": [ { "query": "SELECT * FROM ${data()} WHERE ${column()} IS NOT NULL" } ] } } } } EOF
Replace the following:
-
ENTRY_GROUP_ID: the ID of the entry group that stores your rule template. -
TEMPLATE_ID: the ID of the rule template that you want to update.
Terraform
To update a custom rule template, use the google_dataplex_entry
resource:
resource "google_dataplex_entry" "rule_template" { project = " PROJECT_ID " location = " LOCATION " entry_id = " TEMPLATE_ID " entry_group_id = " ENTRY_GROUP_ID " entry_type = "projects/dataplex-types/locations/global/entryTypes/data-quality-rule-template" aspects { aspect_key = "dataplex-types.global.data-quality-rule-template" aspect { data = jsonencode ({ dimension = "VALIDITY" sqlCollection = [ { query = "SELECT * FROM $${data()} WHERE $${column()} IS NOT NULL" } ] }) } } }
Replace the following:
-
PROJECT_ID: your project ID. -
LOCATION: the location for your rule template (for example,us-central1). -
ENTRY_GROUP_ID: the ID of the entry group that stores your rule template. -
TEMPLATE_ID: the ID of the rule template that you want to update.
Delete a rule template
To delete an existing rule template, select one of the following options:
Console
-
In the Google Cloud console, go to the Data profiling & qualitypage.
-
Go to Rule libraries > Custom.
-
Click the rule library that contains the template you want to delete.
-
In the Rule templateslist, click the template that you want to delete.
-
Click Delete, and then click Deleteagain to confirm.
REST
To delete a custom rule template, delete the entry:
gcurl -X DELETE \ "https:// ${ DATAPLEX_API } /entryGroups/ ENTRY_GROUP_ID /entries/ TEMPLATE_ID "
Replace the following:
-
ENTRY_GROUP_ID: the ID of the entry group that stores your rule template. -
TEMPLATE_ID: the ID of the rule template that you want to delete.
Create a data quality scan using template rules
Use your custom templates to define rules for a data quality scan.
Console
-
In the Google Cloud console, go to the Data profiling & qualitypage.
-
Follow the steps to create a data quality scan , but update the following:
- In the Define scanwindow, in the Credential typemenu, select Service account, and then enter a service account. A service account is mandatory for using rule templates.
- In the Data quality ruleswindow, define the rules to configure for this data quality scan:
- Click Add rules > Template rules.
- You can either select Attach rule to entire table, or in Choose columns, browse and select the columns to apply rules for.
- In Choose rule templates, select the rule templates to use. Only the rule templates in the same location as the scan or in a global location can be used. Alternatively, you can also select system rule templates from the list.
- Click Ok.
- Click Edit rule, and then add rule specific parameters.
- Click Save.
- Select the rules that you want to add, and then click Select. The rules are now added to your current rules list.
- Optional: Repeat the previous steps to add additional rules to the data quality scan.
- Click Continue.
- Proceed with the remaining scan configuration.
- Click Createto only create the scan, or click Run scanto create and immediately run the scan.
REST
To create a data quality scan that references a rule template, specify the templateReference
. Custom rule templates use project-specific paths, while
system rule templates use a global path: projects/dataplex-templates/locations/global/entryGroups/rule-library/entries/<var>SYSTEM_TEMPLATE_ID</var>
.
The following example creates a scan that uses a custom rule template and includes a filter to selectively run rules:
gcurl -X POST "https:// ${ DATAPLEX_API } /dataScans?data_scan_id= DATASCAN_ID " \ --data @- << EOF { "data": { "resource": "//bigquery.googleapis.com/projects/ BIGQUERY_PROJECT_ID /datasets/ DATASET_ID /tables/ TABLE_ID " }, "executionIdentity": { "serviceAccount": { "email": " SERVICE_ACCOUNT_EMAIL " } }, "executionSpec": { "trigger": { "onDemand": {} } }, "type": "DATA_QUALITY", "dataQualitySpec": { "rules": [ { "templateReference": { "name": "projects/ PROJECT_ID /locations/ LOCATION /entryGroups/ ENTRY_GROUP_ID /entries/ TEMPLATE_ID ", "values": { " PARAMETER_NAME ": { "value" : " PARAMETER_VALUE " } } }, "column": " COLUMN_NAME ", "name": " RULE_NAME " } ], "filter": " FILTER_CONDITION " } } EOF
Replace the following:
-
PROJECT_ID: your project ID. -
LOCATION: the location for your rule template and scan (for example,us-central1). -
DATASCAN_ID: the ID of the data quality scan. -
BIGQUERY_PROJECT_ID: the project ID of the BigQuery table. -
DATASET_ID: the BigQuery dataset ID. -
TABLE_ID: the BigQuery table ID. -
SERVICE_ACCOUNT_EMAIL: the email ID of the service account to run the scan. -
ENTRY_GROUP_ID: the ID of the entry group that stores your rule template. -
TEMPLATE_ID: the ID of the custom rule template. -
SYSTEM_TEMPLATE_ID: the ID of the system rule template (for example,non_null_expectation). -
PARAMETER_NAME: the name of an input parameter for the rule template. -
PARAMETER_VALUE: the value for the input parameter. -
COLUMN_NAME: the column to apply the rule to. -
RULE_NAME: a name for the rule instance. -
FILTER_CONDITION: an optional AIP-160 filter string to selectively run rules (for example,name = \"RULE_NAME\").
Terraform
To create a data quality scan that references a rule template, use the google_dataplex_datascan
resource:
resource "google_dataplex_datascan" "scan" { data_scan_id = " DATASCAN_ID " location = " LOCATION " project = " PROJECT_ID " data { resource = "//bigquery.googleapis.com/projects/ BIGQUERY_PROJECT_ID /datasets/ DATASET_ID /tables/ TABLE_ID " } execution_spec { service_account = " SERVICE_ACCOUNT_EMAIL " trigger { on_demand {} } } data_quality_spec { rules { column = " COLUMN_NAME " name = " RULE_NAME " dimension = "VALIDITY" template_reference { name = "projects/ PROJECT_ID /locations/ LOCATION /entryGroups/ ENTRY_GROUP_ID /entries/ TEMPLATE_ID " values = { " PARAMETER_NAME " = { value = " PARAMETER_VALUE " } } } } filter = " FILTER_CONDITION " } }
Replace the following:
-
PROJECT_ID: your project ID. -
LOCATION: the location for your rule template and scan (for example,us-central1). -
DATASCAN_ID: the ID of the data quality scan. -
BIGQUERY_PROJECT_ID: the project ID of the BigQuery table. -
DATASET_ID: the BigQuery dataset ID. -
TABLE_ID: the BigQuery table ID. -
SERVICE_ACCOUNT_EMAIL: the email ID of the service account to run the scan. -
ENTRY_GROUP_ID: the ID of the entry group that stores your rule template. -
TEMPLATE_ID: the ID of the custom rule template. -
PARAMETER_NAME: the name of an input parameter for the rule template. -
PARAMETER_VALUE: the value for the input parameter. -
COLUMN_NAME: the column to apply the rule to. -
RULE_NAME: a name for the rule instance. -
FILTER_CONDITION: an optional AIP-160 filter string to selectively run rules.
Run and monitor data quality scans
After you create a data quality scan, you must run it to validate your data. For more information, see Run a data quality scan .
You can then monitor the scan jobs and view the results. For more information, see View the data quality scan results .
Attach data quality rules to catalog entries
You can declare data quality rules as aspects in Knowledge Catalog to make them searchable and reusable across scans.
BigQuery table
To define rules directly on a BigQuery table entry, select one of the following:
Console
-
In the Google Cloud console, go to the Knowledge Catalog Searchpage.
-
Search for and select the table that you want to attach rules to.
-
Click Data quality > Rules management > Create rules.
-
In the Create ruleswindow, do the following:
- In the Choose create optionmenu, select Create new rule.
- In Choose columns, click Browse. Select the columns to apply rules for.
- In the Choose rule typesmenu, select the rule templates to use. Only the rule templates in the same location as the scan can be used.
- Click Edit rule, and then add rule specific parameters.
-
Click Save.
The Rules managementpage displays all entry rules.
REST
To attach rules to a specific column using the API, patch the @bigquery
entry with a data-rules
aspect targeted to that column:
gcurl -X PATCH "https:// ${ DATAPLEX_API } /entryGroups/@bigquery/entries/projects/ PROJECT_ID /locations/ LOCATION /datasets/ DATASET_ID /tables/ TABLE_ID ?updateMask=aspects&aspect_keys=projects/dataplex-types/locations/global/aspectTypes/data-rules@Schema. COLUMN_NAME " \ --data @- << EOF { "aspects": { "dataplex-types.global.data-rules@Schema. COLUMN_NAME ": { "aspectType": "projects/dataplex-types/locations/global/aspectTypes/data-rules", "data": { "rules": [ { "templateReference": "projects/ PROJECT_ID /locations/ LOCATION /entryGroups/ ENTRY_GROUP_ID /entries/ TEMPLATE_ID ", "column": " COLUMN_NAME ", "values": { " PARAMETER_NAME ": { "value" : " PARAMETER_VALUE " } } } ] } } } } EOF
Replace the following:
-
PROJECT_ID: your project ID. -
LOCATION: the location for your rule template and aspect. -
DATASET_ID: the BigQuery dataset ID. -
TABLE_ID: the BigQuery table ID. -
COLUMN_NAME: the column to apply the rule to. -
ENTRY_GROUP_ID: the ID of the entry group that stores your rule template. -
TEMPLATE_ID: the ID of the rule template. -
PARAMETER_NAME: the name of an input parameter for the rule template. -
PARAMETER_VALUE: the value for the input parameter.
Terraform
To attach rules to a specific column, use the google_dataplex_entry
resource:
resource "google_dataplex_entry" "bq_table_metadata" { project = " PROJECT_ID " location = " LOCATION " entry_id = "bigquery.googleapis.com/projects/ PROJECT_ID /datasets/ DATASET_ID /tables/ TABLE_ID " entry_group_id = "@bigquery" aspects { aspect_key = "dataplex-types.global.data-rules@Schema. COLUMN_NAME " aspect { data = jsonencode ({ rules = [ { name = " RULE_NAME " dimension = "VALIDITY" templateReference = "projects/ PROJECT_ID /locations/ LOCATION /entryGroups/ ENTRY_GROUP_ID /entries/ TEMPLATE_ID " values = { " PARAMETER_NAME " = { value = " PARAMETER_VALUE " } } } ] }) } } }
Replace the following:
-
PROJECT_ID: your project ID. -
LOCATION: the location for your rule template and aspect. -
DATASET_ID: the BigQuery dataset ID. -
TABLE_ID: the BigQuery table ID. -
COLUMN_NAME: the column to apply the rule to. -
ENTRY_GROUP_ID: the ID of the entry group that stores your rule template. -
TEMPLATE_ID: the ID of the rule template. -
PARAMETER_NAME: the name of an input parameter for the rule template. -
PARAMETER_VALUE: the value for the input parameter. -
RULE_NAME: a unique name for the rule.
Business glossary terms
You can attach rules to business glossary terms. Rules attached to terms are automatically inherited by linked BigQuery tables.
Console
-
In the Google Cloud console, go to the Knowledge Catalog Glossariespage.
-
Search for and select the business glossary term.
-
In the Data quality rulessection, click Add.
-
In the Create ruleswindow, do the following:
- In the Choose create optionmenu, select Create new rule.
- In the Choose rule typesmenu, select the rule templates to use. Only the rule templates in the same location as the scan can be used.
- Click Edit rule, and then add rule specific parameters.
- Click Save.
-
Attach the term to a BigQuery table or columns. For more information, see Manage links between terms and data assets .
REST
To attach rules to a term using the API, patch the @dataplex
entry for the
glossary term:
gcurl -X PATCH "https:// ${ DATAPLEX_API } /entryGroups/@dataplex/entries/projects/ PROJECT_ID /locations/ LOCATION /glossaries/ GLOSSARY_ID /terms/ TERM_ID ?updateMask=aspects&aspect_keys=projects/dataplex-types/locations/global/aspectTypes/data-rules" \ --data @- << EOF { "aspects": { "dataplex-types.global.data-rules": { "aspectType": "projects/dataplex-types/locations/global/aspectTypes/data-rules", "data": { "rules": [ { "templateReference": "projects/ PROJECT_ID /locations/ LOCATION /entryGroups/ ENTRY_GROUP_ID /entries/ TEMPLATE_ID ", "column": " COLUMN_NAME ", "values": { " PARAMETER_NAME ": { "value" : " PARAMETER_VALUE " } } } ] } } } } EOF
Replace the following:
-
PROJECT_ID: your project ID. -
LOCATION: the location for your rule template and aspect. -
GLOSSARY_ID: the ID of the business glossary. -
TERM_ID: the ID of the glossary term. -
ENTRY_GROUP_ID: the ID of the entry group that stores your rule template. -
TEMPLATE_ID: the ID of the rule template. -
COLUMN_NAME: the column to apply the rule to. -
PARAMETER_NAME: the name of an input parameter for the rule template. -
PARAMETER_VALUE: the value for the input parameter.
Terraform
To attach rules to a business glossary term, use the google_dataplex_entry
resource:
resource "google_dataplex_entry" "glossary_term_rules" { project = " PROJECT_ID " location = " LOCATION " entry_id = "projects/ PROJECT_ID /locations/ LOCATION /glossaries/ GLOSSARY_ID /terms/ TERM_ID " entry_group_id = "@dataplex" aspects { aspect_key = "dataplex-types.global.data-rules" aspect { data = jsonencode ({ rules = [ { name = " RULE_NAME " dimension = "VALIDITY" templateReference = "projects/ PROJECT_ID /locations/ LOCATION /entryGroups/ ENTRY_GROUP_ID /entries/ TEMPLATE_ID " values = { " PARAMETER_NAME " = { value = " PARAMETER_VALUE " } } } ] }) } } }
Replace the following:
-
PROJECT_ID: your project ID. -
LOCATION: the location for your rule template and aspect. -
GLOSSARY_ID: the ID of the business glossary. -
TERM_ID: the ID of the glossary term. -
ENTRY_GROUP_ID: the ID of the entry group that stores your rule template. -
TEMPLATE_ID: the ID of the rule template. -
PARAMETER_NAME: the name of an input parameter for the rule template. -
PARAMETER_VALUE: the value for the input parameter. -
RULE_NAME: a unique name for the rule.
Import rules from another table
You can import data quality rules from an existing BigQuery table entry to your current table.
Console
-
In the Google Cloud console, go to the Knowledge Catalog Searchpage.
-
Select the table you want to manage rules for.
-
Click Data quality > Rules management.
-
Click Create rules.
-
In the Create ruleswindow, do the following:
- In the Choose create optionmenu, select Import rules from another table.
- In Table, click Browse. Search for and select the source table containing the rules that you want to copy.
- Select the rules. You can also edit the rules.
-
Click Save.
The Rules managementtab displays the new rules.
REST
To import rules, you must fetch the data-rules
aspect from the source entry
and apply it to the target entry.
-
Get the
data-rulesaspect from the source entry:gcurl "https://dataplex.googleapis.com/v1/projects/ PROJECT_ID /locations/ LOCATION /entryGroups/ ENTRY_GROUP_ID /entries/ SOURCE_ENTRY_ID ?view=FULL"
-
Extract the
ruleslist from thedataplex-types.global.data-rulesaspect. -
Attach the rules to a target entry .
Replace the following:
-
PROJECT_ID: your project ID. -
LOCATION: the location of the source entry. -
ENTRY_GROUP_ID: the ID of the entry group for the source entry. -
SOURCE_ENTRY_ID: the ID of the source entry.
-
View data quality rules for BigQuery table
You can view all rules applicable to a table, including rules attached directly and rules inherited from linked glossary terms.
Console
-
In the Google Cloud console, go to the Knowledge Catalog Searchpage.
-
Search for and select the table.
-
Click Data quality > Rules managementto view all rules.
Create a data quality scan using rules from catalog
You can selectively run rules declared on catalog entries in a scan.
Console
-
In the Google Cloud console, go to the Data profiling & qualitypage.
-
Follow the steps to create a data quality scan , but update the following:
- In the Define scanwindow, do the following:
- In the Credential typemenu, select Service account, and then enter a service account. A service account is mandatory for using rule templates.
- For Rule type, select Create with entry based rule.
- In the Data quality rulessection, rules
applicable to the table entry are displayed, including rules inherited
from linked glossary terms. To filter the rules, do the following:
- In the Filter itemsfield, filter items to selectively run rules .
- Click Apply. Filtered rules are displayed.
- Proceed with the remaining scan configuration.
- Click Createto only create the scan, or click Run scanto create and immediately run the scan.
Subsequent runs evaluate rules attached to the entry or inherited from glossary terms as observed at the time of execution.
- In the Define scanwindow, do the following:
REST
To run rules from catalog entries, set enableCatalogBasedRules
to true
.
You can also specify a filter.
To create the scan, use the following code:
gcurl -X POST "https:// ${ DATAPLEX_API } /dataScans?data_scan_id= DATASCAN_ID " \ --data @- << EOF { "type": "DATA_QUALITY", "data": { "resource": "//bigquery.googleapis.com/projects/ PROJECT_ID /datasets/ DATASET_ID /tables/ TABLE_ID " }, "executionIdentity": { "serviceAccount": { "email": " SERVICE_ACCOUNT_EMAIL " } }, "executionSpec": { "trigger": { "onDemand": {} } }, "dataQualitySpec": { "enableCatalogBasedRules": true, "filter": " FILTER_CONDITION " } } EOF
Replace the following:
-
PROJECT_ID: your project ID. -
LOCATION: the location for your data scan. -
DATASCAN_ID: the ID of the data quality scan. -
DATASET_ID: the BigQuery dataset ID. -
TABLE_ID: the BigQuery table ID. -
SERVICE_ACCOUNT_EMAIL: the email ID of the service account to run the scan. -
FILTER_CONDITION: an AIP-160 filter string to selectively run rules (for example,attributes.environment = \"prod\").
Terraform
To run rules from catalog entries, use the google_dataplex_datascan
resource:
resource "google_dataplex_datascan" "scan" { data_scan_id = " DATASCAN_ID " location = " LOCATION " project = " PROJECT_ID " data { resource = "//bigquery.googleapis.com/projects/ PROJECT_ID /datasets/ DATASET_ID /tables/ TABLE_ID " } execution_spec { service_account = " SERVICE_ACCOUNT_EMAIL " trigger { on_demand {} } } data_quality_spec { enable_catalog_based_rules = true filter = " FILTER_CONDITION " } }
Replace the following:
-
PROJECT_ID: your project ID. -
LOCATION: the location for your data scan. -
DATASCAN_ID: the ID of the data quality scan. -
DATASET_ID: the BigQuery dataset ID. -
TABLE_ID: the BigQuery table ID. -
SERVICE_ACCOUNT_EMAIL: the email ID of the service account to run the scan. -
FILTER_CONDITION: an AIP-160 filter string to selectively run rules.
Pricing
Using Knowledge Catalog rule reusability involves the following pricing elements:
- BigQuery charges: BigQuery charges for the job that runs in the scan project. For more information, see BigQuery pricing .
- Knowledge Catalog data quality scan: There's no charge for processing since BigQuery charges for the job.
- Metadata storage:
data-rulesaspect anddata-quality-rule-templateaspect storage is charged as metadata storage. For more information, see Knowledge Catalog pricing .
What's next
- Learn more about auto data quality overview .
- Learn how to use auto data quality scans .
- View a complete list of system rule templates .
- Learn about metadata management .

