RawCountLoader

RawCountLoader is a Loader which is used to generate the rawCount for the number of rows in the database.

It's used by index based queries as well as custom ent queries.

RawCountLoaderFactory

Public Facing LoaderFactory of RawCountLoader used to create new instances of RawCountLoader as needed.

API

interface QueryCountOptions {
    tableName: string;
    groupCol?: string;
    clause?: clause.Clause;
}
declare class RawCountLoader<K extends any> implements Loader<K, number> {
    context?: Context | undefined;
    constructor(options: QueryCountOptions, context?: Context | undefined);
}
declare class RawCountLoaderFactory implements LoaderFactory<ID, number> {
    name: string;
    constructor(options: QueryCountOptions);
    createLoader(context?: Context): any;
}

• tableName: relevant table in the database.
• groupCol: column in the database that can be converted into an IN query when querying for multiple sources
• clause: Clause instance for filtering.

Note that at least one of groupCol and clause must be provided.

Examples

Given the following schema:

src/schema/todo_schema.ts

const TodoSchema = new EntSchema({
  fields: {
    text: StringType(),
    completed: BooleanType({
      index: true,
      defaultValueOnCreate: () => {
        return false;
      },
    }),
    creatorID: UUIDType({
      foreignKey: { schema: "Account", column: "id" },
    }),
  }; 
}); 
export default TodoSchema; 

here are some examples:

• count of open todos of a user. can be used to fetch multiple users at a time

const openTodosCountLoader = new RawCountLoaderFactory({
  tableName: Todo.loaderOptions().tableName,
  groupCol: "creator_id",
  clause: query.Eq("completed", false),
});

generates query like this

SELECT count(1) as count FROM todos WHERE creator_id IN ($1, $2, $3) AND completed = $4 GROUP BY creator_id;

• count of open todos of a user. cannot be used to fetch multiple users at a time

const openTodosCountLoader = new RawCountLoaderFactory({
  tableName: Todo.loaderOptions().tableName,
  clause: query.And(query.Eq("creator_id", user.id, query.Eq("completed", false)),
});

generates query like this

SELECT count(1) as count FROM todos WHERE creator_id = $1 AND completed = $2;

• count of all todos of a user. can be used to fetch multiple users at a time

const allTodosCountLoader = new RawCountLoaderFactory({
  tableName: Todo.loaderOptions().tableName,
  groupCol: "creator_id",
});

generates query like this

SELECT count(1) as count FROM todos WHERE creator_id IN ($1, $2, $3) GROUP BY creator_id;

• count of all todos of a user. cannot be used to fetch multiple users at a time

const allTodosCountLoader = new RawCountLoaderFactory({
  tableName: Todo.loaderOptions().tableName,
  clause: query.Eq("creator_id", user.id),
});

generates query like this

SELECT count(1) as count FROM todos WHERE creator_id = $1;