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Create Detection Rule

For an example of how to create a detection rule for a specific use case, see Get Started with Data Quality.

Before you start

We recommend checking the following topics:

Data Quality - Learn how data quality works in ONE.
Detection and DQ Evaluation Rules - Read more about the types of rules and their role.

Create new detection rule manually

As well as being created from scratch, detection rules can be created from the attribute statistics. For example, create a detection rule for a term identifying North American phone numbers using mask results from an existing data profile.

Only data-based detection rules can be created from attribute statistics.

To create a rule:

Navigate to Data Quality > Rules.
Click Create.
Provide the following information:
- Name: The name of the rule.
- Description (optional): A description of the rule and how to use it.
- Rule definition source (optional): A descriptive name for the data source associated with the rule.
- Stewardship (recommended): Select the user group which are owners of the asset. After you select a group, the list of users assigned to the governance roles within the selected group is displayed.
  
  For more information, see Stewardship.
Click Save to create a draft of the rule.
Before publishing or submitting an approval request, you need to define the rule logic consisting of at least one input attribute and condition. Continue to Rule implementation.

Rule implementation

Once you have created the rule, go to the Implementation tab.

Select rule type

Use the dropdown, and under Term Detection Rules, choose from the following:

Based on data: Data-based rules evaluate the attribute data.
Based on metadata: Metadata-based rules help to apply terms based on information such as the names or descriptions of attributes, catalog items, locations, and data sources, or even attribute comments.

After you select one of the detection rule types you cannot change to another rule type. If you select the wrong type, discard the rule and create another.

Inputs

If you selected Based on metadata in the previous step, proceed to Rule logic.

Add an input attribute by providing a name and selecting the data type.

Input attributes are abstract at this point. The number of input attributes defined here and their rule logic become available when you apply rules to catalog items.

The attribute names can be as you choose and do not affect the implementation.

(Optional) Add terms to the attribute.

Adding terms to input attributes during implementation results in this rule being suggested by the system in the instance an attribute also has this term.

(Optional) Create Variables from your inputs. Within the Variables section, you can apply a range of transformations to your input attribute. For example, apply the rule conditions only on trimmed versions of string attributes. To create variables:

Select a name for your variable. To add fields for additional variables, select Add Variable.

As with the input attribute names, choose a meaningful name or leave as default.
Select the attributes on which the transformations will be applied. Use the dropdown to select from the list of input attributes - you will apply the transformations in the next step.

Alternatively, if you are an advanced user, use the dropdown to select Advanced Expression and define the attribute and the transformations using ONE expression language.

Add transformations using the Add transformation option. The transformations available depend on the data type of the selected attribute: a full list of types and available transformations is provided below.

You can apply multiple transformations to one attribute, but you can only add them in a sensical sequence. For example, if you start with an attribute of data type String and apply the transformation To integer, you will not then be able to add the Uppercase transformation, as this is only available on string.

For the same reason, you can only remove the last transformation in a sequence at any given time. To remove the transformation, hover over the last transformation and use the x to delete.

Expand to see all available transformations

Datatype Available transformations Description

Datatype	Available transformations	Description
`String`	`To float`	Changes data type from string to float.
`To integer`	Changes data type from string to integer.
`To long`	Changes data type from string to long.
`Uppercase`	Converts string characters to uppercase.
`Lowercase`	Converts string characters to lowercase.
`Trim`	Removes spaces from both ends of the string.
`Squeeze spaces`	Trims string and replaces repeated spaces with a single space.
`Remove non-digits`	Removes non-digit characters from string.
`Remove non-letters`	Removes non-letter characters from string.
`Integer`	`To float`	Changes data type from integer to float.
`To date`	Changes data type from integer to date.
`To long`	Changes data type from integer to long.
`Boolean`	`To String`	Changes data type from Boolean to string.
`Date`	`To datetime`	Changes data type from date to datetime.
`To string`	Changes data type from date to string.
`Datetime`	`To date`	Changes data type from datetime to date.
`To string`	Changes data type from datetime to string.
`Long`	`To float`	Changes data type from long to float.
`To string`	Changes data type from long to string.
`To date`	Changes data type from long to date.
`To datetime`	Changes data type from long to datetime.
`Float`	`To string`	Changes data type from float to string.
`Floor`	Rounds to the nearest integer that is less than or equal to float value.
`Ceiling`	Rounds to the nearest integer that is greater than or equal to float value.
`Round`	Rounds to nearest integer.

String

To float

Changes data type from string to float.

To integer

Changes data type from string to integer.

To long

Changes data type from string to long.

Uppercase

Converts string characters to uppercase.

Lowercase

Converts string characters to lowercase.

Trim

Removes spaces from both ends of the string.

Squeeze spaces

Trims string and replaces repeated spaces with a single space.

Remove non-digits

Removes non-digit characters from string.

Remove non-letters

Removes non-letter characters from string.

Integer

To float

Changes data type from integer to float.

To date

Changes data type from integer to date.

To long

Changes data type from integer to long.

Boolean

To String

Changes data type from Boolean to string.

Date

To datetime

Changes data type from date to datetime.

To string

Changes data type from date to string.

Datetime

To date

Changes data type from datetime to date.

To string

Changes data type from datetime to string.

Long

To float

Changes data type from long to float.

To string

Changes data type from long to string.

To date

Changes data type from long to date.

To datetime

Changes data type from long to datetime.

Float

To string

Changes data type from float to string.

Floor

Rounds to the nearest integer that is less than or equal to float value.

Ceiling

Rounds to the nearest integer that is greater than or equal to float value.

Round

Rounds to nearest integer.

Rule logic

Provide the rule conditions and an explanation of the result.

There are two ways to do this: through the Condition Builder or via Advanced Expression:

Select Advanced Expression to leverage ONE expressions in your rule condition (see ONE Expressions).

Select Condition Builder to define the rule logic using the predefined options.

Keep in mind that if you’re using the Condition Builder to define the rule logic, a record must pass all the conditions for the rule to result in a term being added (the default logical operator between conditions is AND).

If your detection rule should be less strict and use the logical operator OR, try the Advanced Expression mode.

If you selected Advanced Expression, provide the expression in the space provided and proceed to Test rule.

If you selected Condition Builder:

Select the input attribute or variable to use in the condition for data-based rules, or the relevant metadata, for example, attribute_name, source_name or catalogItem_description, if you are creating a metadata-based rule.
- Data-based detection rule
- Metadata-based detection rule

Select any required modifiers, for example, Trim or Round. Different modifiers are available for string and integer inputs.

Only string modifiers are available in metadata-based rule conditions.

Expand to see all available modifiers

Modifier Description

Modifier	Description
`Value`	The given value of an attribute.
`Uppercase`	Uppercase version of string.
`Lowercase`	Lowercase version of string.
`Trim`	Removes any whitespaces from both sides of strings.
`Trim left`	Removes any leading whitespaces from strings.
`Trim right`	Removes any trailing whitespaces from strings.
`Squared`	Squares the value of an integer, float, or long data type attributes.
`Round`	Rounds the value of an integer, float, or long data type attributes to the nearest whole number.
`Average`	Averages the value of integer, float, or long data type attributes (available only when using aggregation rules and grouping).
`Min`	The minimum of string, integer, or long data types attributes (available only when using aggregation rules and grouping).
`Max`	The maximum of string, integer, or long data type attributes (available only when using aggregation rules and grouping).
`Sum`	The sum of of string, integer, or long data type attributes (available only when using aggregation rules and grouping).

Value

The given value of an attribute.

Uppercase

Uppercase version of string.

Lowercase

Lowercase version of string.

Trim

Removes any whitespaces from both sides of strings.

Trim left

Removes any leading whitespaces from strings.

Trim right

Removes any trailing whitespaces from strings.

Squared

Squares the value of an integer, float, or long data type attributes.

Round

Rounds the value of an integer, float, or long data type attributes to the nearest whole number.

Average

Averages the value of integer, float, or long data type attributes (available only when using aggregation rules and grouping).

Min

The minimum of string, integer, or long data types attributes (available only when using aggregation rules and grouping).

Max

The maximum of string, integer, or long data type attributes (available only when using aggregation rules and grouping).

Sum

The sum of of string, integer, or long data type attributes (available only when using aggregation rules and grouping).

Select the condition, for example, matches_mask or contains, and provide the necessary requirements. The options available depend on the data type of the input attributes.

Expand to see all available conditions

Condition Description

Is empty

When the input is not filled.

This checks if the field is filled, but a field will not be identified as empty if it is filled with: NULL, Null, null, ., ,, -, _, N/A, n/a, and so on.

Is not empty

When the input is filled.

Is the same as

When the input is the same as the value you define.

Is the same as attribute

When the attribute is the same as the attribute you select.

Is not the same as

When the input is not the same as the value you define.

Is not the same as attribute

When the attribute is not the same as the attribute you select.

Is from the following list

When the attribute belongs to the list you define.

Is not from the following list

When the attribute does not belong to the list you define.

Has length of

Is the same as the length you define.

Contains

When the input contains a substring you define.

Is from catalog item

When input belongs to a lookup item built from specified catalog item and attribute.

To make sure the rule always uses the latest data available, select ON DATA CHANGE in Data updates. If you select a catalog item that is not managed using ONE Data, no automatic updates are available.

For more information, see Use Lookups in Rules.

Is not from catalog item

When input doesn’t belong to a lookup item built from specified catalog item attribute or reference data in ONE Data.

Is from reference data

When attribute input belongs to the lookup file you select.

Is not from reference data

When attribute input does not belong to the lookup file you select.

Matches mask

When input corresponds to the mask you define.

Does not match mask

When input does not correspond to the mask you define.

Matches regexp

When input corresponds to the regular expression you define.

Does not match regexp

When input does not correspond to the regular expression you define.

Is true

When Boolean input is true.

Is false

When Boolean input is false.

Is unique

When aggregated group is unique.

Is not unique

When aggregated group is not unique.

Test rule

You can optionally test the rule by clicking Test Rule and trying different inputs in the Test section. The results for each input are shown automatically in Message next to the test input row.

Publish rule

After the changes are implemented, they need to be published.

Next steps

Attributes matching the defined condition are added to the term associated with this rule.

Apply your newly-created detection rule to a term. See Add Rules to Terms.

Once the rule is applied to a term, you can see this term in the Summary and the Detect term sections of the rule implementation screen.

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