{{#set:Description=Documentation for generating and querying automatic IDs using Page Forms and Cargo.}}

Automatic ID Generation for Cargo Tables

This page documents the workflow for generating automatic, composite IDs using the Page Forms and Cargo extensions.

Overview

While Page Forms does not have a "native" ID generator button, unique IDs can be constructed by:

Combining user-input attributes in the storage template.
Using the form's page name formula to ensure uniqueness.
Enforcing uniqueness via form validation.

1. Template Logic (The "Store" Method)

To create an ID from a combination of attributes, logic is placed inside the `{{#cargo_store}}` function.

Example Cargo Declaration

Define your table in your Schema template:

{{#cargo_declare:
_table = Projects
|ProjectID = String
|Category = String
|Year = Integer
}}

Example Cargo Store

In your data template, concatenate the fields to create the `ProjectID`:

<includeonly>
{{#cargo_store:
_table = Projects
|ProjectID = {{{Category|}}}-{{{Year|}}}-{{#time:U}} <!-- Category-Year-UnixTimestamp -->
|Category = {{{Category|}}}
|Year = {{{Year|}}}
}}
</includeonly>

2. Form Definition

To ensure the user doesn't create a duplicate ID, use the `unique` and `page name` parameters in Page Forms.

Page Name Formula

In the `{{{info}}}` tag, define how the page is named automatically:

{{{info|page name=<Projects[Category]>-<Projects[Year]>-<unique number;start=001>}}}

Field Validation

Force the form to check if an ID already exists:

{{{field|ProjectID|unique|input type=text|hidden}}}

3. Querying Records

To retrieve data using your custom ID, use the `{{#cargo_query}}` function as documented on MediaWiki.org.

Filter by Composite ID

{{#cargo_query:
|tables = Projects
|fields = _pageName=Page, Category, Year
|where = ProjectID = 'Hardware-2024-171523421'
|format = table
}}

Filter using Wildcards

To find all projects from a specific category using the ID prefix:

{{#cargo_query:
|tables = Projects
|fields = ProjectID, Year
|where = ProjectID LIKE 'Hardware-%'
|format = ul
}}

Extensions Used

Page Forms: Handles the user interface and page naming.
Cargo: Handles data storage and querying.
ParserFunctions: Used for string manipulation and date formatting.