AppML Defining Models
An AppML model is a JSON configuration file that names the data source for a page and declares which fields and CRUD actions the page is permitted to use against it.
The Model as a Contract Between Page and Data
In AppML, a model is not markup and not code - it is a small JSON document that sits between the HTML page and the underlying data source. It tells the AppML library where the data comes from (a database table, a stored query, or in simpler setups a flat file), which fields exist on each record, and which operations - listing, inserting, updating, deleting - are allowed on that data. The HTML page never talks to the database directly; it talks to the model, and the model talks to whatever sits behind it.
- A data source reference (a connection name, table name, or file path)
- An optional ordering or filter rule for how records are listed
- A fields definition describing each column's name and, optionally, its type or validation
- A set of allowed actions: list, insert, update, delete
Example: an employees model
{
"connection": "hyring_learn_db",
"table": "employees",
"orderby": "lastname",
"fields": [
{ "name": "id", "type": "number", "primaryKey": true },
{ "name": "firstname", "type": "text", "required": true },
{ "name": "lastname", "type": "text", "required": true },
{ "name": "department", "type": "text" },
{ "name": "salary", "type": "number" }
],
"actions": {
"list": true,
"insert": true,
"update": true,
"delete": true
}
}Once a model exists, the HTML page links to it with a single attribute, and every {{fieldname}} placeholder in that page's markup is resolved against the fields the model exposes. If a field isn't declared in the model, it can't be displayed or edited on the page - the model is the single source of truth for what data is reachable.
Linking a page to its model
<html>
<head>
<script src="appml.js"></script>
</head>
<body appml-data="employees.json">
<div appml-repeat="records">
{{firstname}} {{lastname}} - {{department}}
</div>
</body>
</html>Because the model is just JSON, it can be edited without touching the page's HTML or any server code - adding a field, disabling delete, or changing the sort order is a configuration change, not a rewrite.
Exercise: AppML Models
What does an AppML model primarily define?
