rules-rule-declare-decision-table

name	rules-rule-declare-decision-table
description	Schema and authoring guide for Pega Decision Table rules (Rule-Declare-DecisionTable), including column structure, delegated restrictions, multi-result property columns, page list macros, and examples

Overview

A Decision Table (Rule-Declare-DecisionTable) evaluates tabular logic: conditions are columns, rows are implicit (encoded as parallel arrays), and evaluation is top-to-bottom first-match-wins. If no row matches, pyDefaultResult is returned.

Row 1: Col1.Condition[1] AND Col2.Condition[1] → Results[1]
Row 2: Col1.Condition[2] AND Col2.Condition[2] → Results[2]
Default: → pyDefaultResult

String List Serialization (CRITICAL)

pyCondition and pyResults are String Lists. They accept only simple string arrays. Two other formats fail:

Format	Result
Indexed notation ("pyCondition(1)": "80")	HTTP 500 — JSON-to-clipboard conversion error
Array of objects ([{"pxObjClass": "Embed-DecisionTable-Condition", ...}])	HTTP 500 — "pyResults was of mode String List while expecting Page List"
Simple string arrays ([">=80", ">=0"])	Works

pyCondition values concatenate operator and value into a single string:

"pyCondition": [">=80", ">=0"]
"pyCondition": ["<0.20", ">=0.20"]
"pyCondition": ["Active", "Inactive"]

pyResults values are plain strings:

"pyResults": ["Pass", "Fail"]

Read/write symmetry: Both GET and create-rule / update-rule use the same simple array format.

Row Definition Fields

pyColumns and pyResults are required when defining rows in a decision table. Omitting both creates a bare-shell rule with no columns or rows, which is valid for an initial create payload and can be populated later through Dev Studio.

Field	Description
pyColumns	Array of Embed-DecisionTable-Column — required when defining rows
pyResults	Result values — simple string array — required when defining rows

Column Structure

Each column is an Embed-DecisionTable-Column inside the pyColumns array:

Field	Required	Description
pyProperty	Yes	.PropertyName (case property) or Param.Name (parameter)
pyPropertyLabel	No	Human-readable column label
pyColumnDataType	No	"integer", "decimal", "text", "date", "truefalse" — Pega auto-corrects if mismatched with property type
pyCondition	Yes	Simple string array — operator+value concatenated per row
pyDefaultOperator	No	Default operator for Dev Studio display ("=", "!=", ">=", "<=", ">", "<")
pyUseRange	No	"false" (range conditions flag)
pyUseRangeMax	No	"false" (range max flag)
pyOrConditions	No	OR conditions array — see decision-table-or-conditions

Condition value format: Operator concatenated with value as a single string. All values are strings regardless of data type:

"pyCondition": [">=80", "<80"]
"pyCondition": ["Active", "Inactive"]
"pyCondition": [">=20230601", "<20230601"]

Date format: YYYYMMDD as quoted strings prefixed with operator (e.g., ">=20230601").

Column Access Control

Set pyHasAccess: "true" on a column to enable per-column access restrictions. When enabled, the server automatically scaffolds pyColumnRestrictions and pyOrConditions structures. These scaffolds do not need to be included in the payload — they are server-generated.

OR Conditions

See decision-table-or-conditions for multi-value matching within a single row.

Multi-Result Decision Tables

See decision-table-multi-result for pyPropertyColumns, pyDefaultResultPropSet, embedded quotes convention, and the two patterns (Lookup Table vs List Builder).

Page List Macros in Property Paths

See decision-table-page-list-macros for <APPEND>/<LAST> macros and pyPagesAndClasses declarations when targeting page lists.

Allowed Values and SET Side-Effects

See decision-table-allowed-values for the pyAllowedValues vocabulary pattern, SET side-effects that fire per return value, and when to use this feature vs plain pyResults.

Initial Property Set (pyInitialPropSet)

Optional "Preset Properties" block — an array of Embed-ModelParams entries that set properties unconditionally before any row evaluation. Each entry has pyPropertiesName (target property) and pyPropertiesValue (a Pega expression).

Omit for most tables — adding entries flags the rule as "Advanced" in Dev Studio.

Gotchas

• update-rule supports partial updates. Send just pyResults to change result values without resending pyColumns/pyCondition.
• Row count alignment. Every pyCondition array must have the same length as pyResults. Misalignment causes undefined behavior.
• Row order = evaluation priority. Most-specific rows first.
• Row shadowing. A higher-priority row shadows a lower row when its conditions are a superset of (or equal to) the lower row's conditions — the lower row becomes unreachable. Example: Row 1 with >=50 shadows Row 2 with >=80 because any input matching >=80 also matches >=50, so Row 1 wins. When a test returns an unexpected result, check whether a higher row's conditions subsume the intended row. Fix by reordering (most-specific first) or narrowing the higher row's conditions.
• pyColumnPreferences is cosmetic. Dev Studio column widths — safe to omit.

Examples

Rule-level (examples/)

Each non-stub example shows a single-step create-rule payload with columns and rows included. Auto-filled fields are omitted from all examples.

Skill	Description
Stub Decision Table	Bare shell — identity + defaults, no columns, no rows
Multi-Column Mixed Types	3 columns (integer + decimal + text), 3 rows, mixed data types
Date Columns	3 columns (text + date + date), 3 rows, dual date range pattern
Text-Only Approval	3 columns (all text), 3 rows, approval/gate workflow pattern
Parameter Lookup	1 column (Param.Name reference), 4 rows, parameter-based lookup
Multi-Result Lookup Table	Multi-result lookup table — condition maps to multiple output properties, first-match
Multi-Result List Builder	Multi-result list builder — <APPEND>/<LAST> macros, pyEvaluateAllRows: "yes"
Allowed Values with Property Assignments	pyAllowedValues — registers result values and allows specific values for additional target properties when each result is selected
Preset Properties (pyInitialPropSet)	pyInitialPropSet preset properties — sets properties unconditionally before any row evaluation