331 Schema Output

Trace schema.idea into generated schema classes before debugging higher-level behavior. Schema output matters because it is the first generated proof that Stackpress understood a model, its fields, its defaults, and its validation rules.

Previously: The previous course, Generation, connected schema.idea to generated client output. This course opens one generated model schema and compares it back to the source model.

331.1. Where To Look

In a scaffolded app, generated Article schema output lives under client-source/Article. Start with the schema class and one generated column file.

client-source/Article/ArticleSchema.ts
client-source/Article/columns/TitleColumn.ts

These files are generated output, not source files to hand-edit. They are useful because they show how Stackpress interpreted the Article model after generation ran.

331.2. The Schema Class

ArticleSchema.ts imports every generated column class, builds a columns map, builds a Zod shape, and exposes helper methods such as defaults, assert, filter, populate, serialize, and unserialize. This is the generated schema contract that later store, action, and UI code can rely on.

this.columns = {
  id: new IdColumn(),
  profileId: new ProfileIdColumn(),
  title: new TitleColumn(),
  slug: new SlugColumn()
};

this.shape = z.object({
  id: this.columns.id.shape,
  profileId: this.columns.profileId.shape,
  title: this.columns.title.shape,
  slug: this.columns.slug.shape
});

This shortened example shows the pattern without listing every Article field. The column map gives each field a generated class, and the Zod shape combines those columns into one schema-level validation shape.

331.3. A Column File

TitleColumn.ts is where the generated title field becomes a concrete column contract. It names the column, defines its Zod shape, carries its default behavior, validates input, and serializes values.

public readonly name = 'title';

public constructor() {
  this.shape = z
    .string()
    .describe('Title of the article.')
    .refine(
      (data: any) =>
        typeof data !== 'undefined' && data !== null && String(data) !== '',
      { message: 'Title is required' }
    );
}

This example traces back to the title String field and @is.required("Title is required") metadata in schema.idea. The generated column turns that idea metadata into runtime validation behavior.

331.4. What To Inspect

When a field behaves incorrectly, inspect whether the generated schema has the field, default, assertion message, and serialization behavior you expected. If the generated output is missing the expected meaning, the fix usually belongs in schema.idea or the generator source, not inside the generated file.

For example, if TitleColumn does not contain the required-message refinement, check whether the title field still has @is.required("Title is required") in schema.idea. Regenerate after fixing the source so the output can be recreated consistently.

331.5. Mistakes To Avoid

Generated schema output is evidence, not the first place to fix product rules. Use it to find the mismatch, then move upstream to the idea source or generator that produced the file.

331.5.1. Patch A Generated Column

// client-source/Article/columns/TitleColumn.ts
this.shape = z.string().min(1, 'Title is required');

This might make the current generated file look correct, but the next generation run can overwrite it. If the title should be required, fix or confirm the @is.required("Title is required") source in schema.idea, then regenerate.

331.5.2. Debug Admin UI Before Schema Output

The admin form accepts an empty title.

This symptom may appear in the admin page, but the first generated evidence is the schema and column output. If TitleColumn.ts does not contain the expected required refinement, the admin form is showing a schema problem rather than creating one by itself.

331.5.3. Blame The Generator Before Checking Source

title String @label("Title")

This field has a label, but it does not show the required validator from the earlier example. Before treating missing validation as a generator bug, confirm that the field, attribute, default, or validator exists in schema.idea.

Learning checkpoint: Before moving on, make sure you can trace one schema.idea field into a generated schema class and a generated column file. You should also know why source fixes belong upstream of generated output.

Next course: Continue with SQL Output. That course follows the same generated model into store and action behavior.