| 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 |
