How can we configure a TypeORM ViewEntity's ViewColumn to be of JSON type?

In TypeORM, ViewEntity represents database views, while ViewColumn defines columns within view entities. To configure a ViewColumn as JSON type, ensure your database supports JSON fields and specify the correct type in the ViewColumn definition.

Assuming PostgreSQL is used, which natively supports JSON types, the configuration for ViewEntity and ViewColumn is as follows:

typescript
import {ViewEntity, ViewColumn} from "typeorm";

@ViewEntity({
    expression: `\n        SELECT\n            id,\n            details\n        FROM\n            orders\n    `\n})
export class OrderView {
    @ViewColumn()
    id: number;

    // Configure as JSON type
    @ViewColumn({ type: "json" })
    details: any;
}

In this example, OrderView serves as a view entity representing a database view. The view selects id and details from the orders table. The details column is explicitly configured as JSON type to store and query JSON data.

When querying data from this view entity, the details column will be provided directly as a JSON object, simplifying the handling of complex data structures in applications.

Notes

1. Verify database support for JSON types. Not all databases natively support JSON (e.g., MySQL versions prior to 5.7.8, SQL Server).
2. In practical applications, JSON types enable flexible data structures, but consider query performance and data structure management.
3. When using TypeORM with ViewEntity, ensure the view is properly created and configured in the database.

By following this approach, you can effectively utilize JSON-type ViewColumn in TypeORM to handle complex data structures more flexibly within your applications.