Working with Data Models

Nexus uses a flexible schema system that lets you define custom data models for your application. This guide covers creating schemas, defining relationships, validating data, and querying your models efficiently.

Defining a Schema

Schemas are defined using our declarative JSON format:

{
  "name": "product",
  "fields": [
    { "name": "title", "type": "string", "required": true },
    { "name": "price", "type": "number", "min": 0 },
    { "name": "category", "type": "relation", "target": "category" },
    { "name": "tags", "type": "string[]", "maxItems": 10 }
  ]
}

Relationships

Nexus supports one-to-one, one-to-many, and many-to-many relationships between models. Use the relation field type and specify the target model:

{ "name": "author", "type": "relation", "target": "user", "cardinality": "one" }
{ "name": "tags", "type": "relation", "target": "tag", "cardinality": "many" }

Querying Data

Use the query API to filter, sort, and paginate your data:

const products = await client.data.query('product', {
  filter: { category: 'electronics', price: { $lt: 100 } },
  sort: { field: 'created_at', order: 'desc' },
  limit: 20,
  offset: 0
});

Validation

Built-in validation ensures data integrity. Define validation rules directly in your schema, and the API will reject invalid data with descriptive error messages.