Chapter 20

Data page calls

Most “the data page returns nothing” problems are really “the value never arrived under the right name”. Here is every parameter and query situation, with something to try for each.

Updated 4 Nov 2026Pega 24 – 26

Words you will meet

getData
Parameters
Query

On this page3

01Parameters, one rule at a time
02Big lists: query, sort, paging
03Every call scenario

Data pages

Parameters, one rule at a time.

The same decisions a real component makes are laid out as a workbench. Type what an author would type, say what the data page declares, and see exactly what would be sent, or why nothing is.

Parameter workbenchTry it: try the presets, then change what the data page declares

Parameters setting (what the author types)

What the data page declares

Case properties right now

.PatientID = P-1042
.Region = APAC
.NotesText = Follow up in a week
.Empty = (blank)

The data page is called

Payload sent to getData

{  "dataViewParameters": {    "Region": "APAC"  }}

One parameter is declared (Region), so the value goes there.

Large data

Big lists: query, sort, paging.

When a list is too big to hold in the browser, the server does the filtering, sorting and slicing. This builds the whole request the way Pega’s own tables send it, with the reason for each part.

Query builderTry it: add filters, change the sort and the page

Columns to return (select)

Filters, joined with AND

Sort by

PagePage size

Also send a fixed parameter (Region = APAC)

The request

{  "dataViewParameters": {    "Region": "APAC"  },  "query": {    "select": [      {        "field": "Name"      },      {        "field": "Status"      },      {        "field": "Region"      }    ],    "filter": {      "logic": "T1",      "filterConditions": {        "T1": {          "lhs": {            "field": "Name"          },          "comparator": "CONTAINS",          "rhs": {            "value": "smith"          },          "ignoreCase": true        }      }    },    "sortBy": [      {        "field": "Name",        "type": "ASC"      }    ]  },  "paging": {    "pageNumber": 1,    "pageSize": 25  },  "includeTotalCount": true}

Pega’s data API answers “Query does not contain select” to a filter or a sort on its own, so the list of columns is always sent.
Each filled filter becomes a numbered condition (T1, T2…), joined with AND. A filter with no value is left out.
ignoreCase is sent for text only. Sent on a number, date or dropdown it can fail the query.
A number filter sends a real number, so the comparison is numeric.
Pega sorts the whole result, not just the page you see.
With no filters there is no filter key, and a sort alone does not send an empty one.

Reference

Every call scenario.

The situations that come up again and again, each with what you type, what is sent and the trap to avoid.

Call scenariosTry it: open each one

You type
Parameters is blank
What is sent
{ }
The data page runs with none.
Fine for a data page with no parameters, or whose parameters are all optional. If a required one is missing, the server answers with a 400 and the console shows which.

Your turn

Questions and comments

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