kysely/dist/esm/dynamic/dynamic.d.ts

Type safe SQL query builder

import { DynamicReferenceBuilder } from './dynamic-reference-builder.js';
export declare class DynamicModule {
    /**
     * Creates a dynamic reference to a column that is not know at compile time.
     *
     * Kysely is built in a way that by default you can't refer to tables or columns
     * that are not actually visible in the current query and context. This is all
     * done by typescript at compile time, which means that you need to know the
     * columns and tables at compile time. This is not always the case of course.
     *
     * This method is meant to be used in those cases where the column names
     * come from the user input or are not otherwise known at compile time.
     *
     * WARNING! Unlike values, column names are not escaped by the database engine
     * or Kysely and if you pass in unchecked column names using this method, you
     * create an SQL injection vulnerability. Always __always__ validate the user
     * input before passing it to this method.
     *
     * There are couple of examples below for some use cases, but you can pass
     * `ref` to other methods as well. If the types allow you to pass a `ref`
     * value to some place, it should work.
     *
     * ### Examples
     *
     * Filter by a column not know at compile time:
     *
     * ```ts
     * async function someQuery(filterColumn: string, filterValue: string) {
     *   const { ref } = db.dynamic
     *
     *   return await db
     *     .selectFrom('person')
     *     .selectAll()
     *     .where(ref(filterColumn), '=', filterValue)
     *     .execute()
     * }
     *
     * someQuery('first_name', 'Arnold')
     * someQuery('person.last_name', 'Aniston')
     * ```
     *
     * Order by a column not know at compile time:
     *
     * ```ts
     * async function someQuery(orderBy: string) {
     *   const { ref } = db.dynamic
     *
     *   return await db
     *     .selectFrom('person')
     *     .select('person.first_name as fn')
     *     .orderBy(ref(orderBy))
     *     .execute()
     * }
     *
     * someQuery('fn')
     * ```
     *
     * In this example we add selections dynamically:
     *
     * ```ts
     * const { ref } = db.dynamic
     *
     * // Some column name provided by the user. Value not known at compile time.
     * const columnFromUserInput = req.query.select;
     *
     * // A type that lists all possible values `columnFromUserInput` can have.
     * // You can use `keyof Person` if any column of an interface is allowed.
     * type PossibleColumns = 'last_name' | 'first_name' | 'birth_date'
     *
     * const [person] = await db.selectFrom('person')
     *   .select([
     *     ref<PossibleColumns>(columnFromUserInput),
     *     'id'
     *   ])
     *   .execute()
     *
     * // The resulting type contains all `PossibleColumns` as optional fields
     * // because we cannot know which field was actually selected before
     * // running the code.
     * const lastName: string | undefined = person.last_name
     * const firstName: string | undefined = person.first_name
     * const birthDate: string | undefined = person.birth_date
     *
     * // The result type also contains the compile time selection `id`.
     * person.id
     * ```
     */
    ref<R extends string = never>(reference: string): DynamicReferenceBuilder<R>;
}