DB Index

A DB Index (or Database Index) is a commonly queried field used to speed up searches in a DB Table.

DB Socket

A DB Socket (or Database Socket) is the interface layer between standard Python queries and raw SQL or MongoDB query language.

DB Table

A set of data inside the Database which has a common ObjectId. The table name follows SQL conventions which is also known as a collection in MongoDB.

Hash Index

A index that hashes the information contained in the object in a reproducible manner. This hash index is only used to find duplicates and should not be relied upon as it may change in the future.


A unique 3D representation of a molecule. Any changes to the protonation state, multiplicity, charge, fragments, coordinates, connectivity, isotope, or ghost atoms represent a change in the molecule.


A ObjectId (or Database ID) is a unique ID for a given row (a document or entry) in the database that uniquely defines that particular row in a DB Table. These rows are automatically generated and will be different for every database, but outlines ways to reference other rows in the database quickly. A ObjectId is unique to a DB Table.


On-node computations, these can either be a single computation (energy, gradient, property, etc.) or a series of calculations such as a geometry optimization.

Queue Adapter

The interface between QCFractal’s internal queue representation and other queueing systems such as Dask or Fireworks.


A document that contains all results (or links) of a given computation.


Iterative workflows where the required computations are distributed via the queue and then are processed on the server to acquire the next iteration of calculations.