Separating Entity Definition
You can define an entity and its columns right in the model, using decorators. But some people prefer to define an entity and its columns inside separate files which are called "entity schemas" in TypeORM.
Simple definition example:
import { EntitySchema } from "typeorm"
export const CategoryEntity = new EntitySchema({
name: "category",
columns: {
id: {
type: Number,
primary: true,
generated: true,
},
name: {
type: String,
},
},
})
Example with relations:
import { EntitySchema } from "typeorm"
export const PostEntity = new EntitySchema({
name: "post",
columns: {
id: {
type: Number,
primary: true,
generated: true,
},
title: {
type: String,
},
text: {
type: String,
},
},
relations: {
categories: {
type: "many-to-many",
target: "category", // CategoryEntity
},
},
})
Complex example:
import { EntitySchema } from "typeorm"
export const PersonSchema = new EntitySchema({
name: "person",
columns: {
id: {
primary: true,
type: "int",
generated: "increment",
},
firstName: {
type: String,
length: 30,
},
lastName: {
type: String,
length: 50,
nullable: false,
},
age: {
type: Number,
nullable: false,
},
},
checks: [
{ expression: `"firstName" <> 'John' AND "lastName" <> 'Doe'` },
{ expression: `"age" > 18` },
],
indices: [
{
name: "IDX_TEST",
unique: true,
columns: ["firstName", "lastName"],
},
],
uniques: [
{
name: "UNIQUE_TEST",
columns: ["firstName", "lastName"],
},
],
})
If you want to make your entity typesafe, you can define a model and specify it in schema definition:
import { EntitySchema } from "typeorm"
export interface Category {
id: number
name: string
}
export const CategoryEntity = new EntitySchema<Category>({
name: "category",
columns: {
id: {
type: Number,
primary: true,
generated: true,
},
name: {
type: String,
},
},
})
When using the
Decorator
approach it is easy to extend
basic columns to an abstract class and simply extend this. For example, your id
, createdAt
and updatedAt
columns may be defined in such a BaseEntity
. For more details, see the documentation on concrete table inheritance.When using the
EntitySchema
approach, this is not possible. However, you can use the Spread Operator
(...
) to your advantage.Reconsider the
Category
example from above. You may want to extract
basic column descriptions and reuse it across your other schemas. This may be done in the following way:import { EntitySchemaColumnOptions } from "typeorm"
export const BaseColumnSchemaPart = {
id: {
type: Number,
primary: true,
generated: true,
} as EntitySchemaColumnOptions,
createdAt: {
name: "created_at",
type: "timestamp with time zone",
createDate: true,
} as EntitySchemaColumnOptions,
updatedAt: {
name: "updated_at",
type: "timestamp with time zone",
updateDate: true,
} as EntitySchemaColumnOptions,
}
Now you can use the
BaseColumnSchemaPart
in your other schema models, like this:export const CategoryEntity = new EntitySchema<Category>({
name: "category",
columns: {
...BaseColumnSchemaPart,
// the CategoryEntity now has the defined id, createdAt, updatedAt columns!
// in addition, the following NEW fields are defined
name: {
type: String,
},
},
})
You can use embedded entities in schema models, like this:
export interface Name {
first: string
last: string
}
export const NameEntitySchema = new EntitySchema<Name>({
name: "name",
columns: {
first: {
type: "varchar",
},
last: {
type: "varchar",
},
},
})
export interface User {
id: string
name: Name
isActive: boolean
}
export const UserEntitySchema = new EntitySchema<User>({
name: "user",
columns: {
id: {
primary: true,
generated: "uuid",
type: "uuid",
},
isActive: {
type: "boolean",
},
},
embeddeds: {
name: {
schema: NameEntitySchema,
prefix: "name_",
},
},
})
Be sure to add the
extended
columns also to the Category
interface (e.g., via export interface Category extend BaseEntity
).Of course, you can use the defined schemas in your repositories or entity manager as you would use the decorators. Consider the previously defined
Category
example (with its Interface
and CategoryEntity
schema) in order to get some data or manipulate the database.// request data
const categoryRepository = dataSource.getRepository<Category>(CategoryEntity)
const category = await categoryRepository.findOneBy({
id: 1,
}) // category is properly typed!
// insert a new category into the database
const categoryDTO = {
// note that the ID is autogenerated; see the schema above
name: "new category",
}
const newCategory = await categoryRepository.save(categoryDTO)
Last modified 3mo ago