10. Glossary

Access Control

Security verification done by xGT to enable or disable access to data based on the user’s authenticated identity.

Administrator Label

Token enabling privileged access to the xGT server to be used by system administrators.

Authentication

Process by which a user requesting access to xGT is validated.

CRUD

Abbreviation for Create, Read, Update, Delete when referring to frame labels.

Cypher

Cypher is Neo4j’s graph query language that allows users to store and retrieve data from Neo4j’s graph database. See OpenCypher for more details.

Egest

Process of extracting data out of xGT, especially when referring to large data sets.

Frame

A frame is a structured collection of homogeneous data in which all elements in the frame, called rows, have the same number of elements.

Frame Label

A security label attached to one of four sets on a frame: the frame’s create, read, update, or delete labels.

Frame Access Control

Access control checks for the entire frame.

Fully qualified name

The completely specified name of an xGT frame, including its namespace: namespace__Frame.

Ingest

Process of loading data into xGT, especially when referring to large data sets.

Job

A unit of asynchronous execution inside xGT.

Job History

Set of completed jobs in an xGT server.

Kerberos Principal

Name of a well-known entity in the Kerberos authentication framework. Can be the name of a machine, user or service.

LDAP

Lightweight Directory Access Protocol, server-based directory. Can be used by xGT for authentication via PAM.

Locale

Software module to support lexicographic string sorting under different languages’ rules.

Logging Component

Module inside the xGT server for which logging verbosity can be controlled individually.

Namespace

Set of uniquely-named frames in the xGT server. Each namespace has a unique name within the xGT system.

Metrics

Statistical data samples collected by the xGT server to enable query planning and optimization.

PAM

Pluggable Authentication Modules, flexible and configurable Linux service used by xGT to authenticate user connections.

Query Section

Part of a query producing a partial answer set to be processed further.

Row

An element of a frame: a vertex in a vertex frame, an edge in an edge frame, or a row in a result frame.

Row Label

A security label attached to a row in a frame.

Row Label Universe

The set of possible row labels that can be attached to any row in a frame. Each frame has its own universe.

Row Access Control

Access control checks for each individual row in a frame.

Sandbox

Subdirectory within the server on which Input/Output operations are permitted.

Security Labels

xGT uses the term “security labels” to refer to the tokens enabling or disabling certain accesses or modifications to data in the server.

SSL

Secure Sockets Layer, protocol used by xGT to enable encrypted communication between client and server.

System Frames

Special frames used by the xGT server to maintain its state, under the xgt namespace.

TQL

The Trovares Query Language is a subset of Cypher, adapted to work with xGT’s strongly typed property graph data model.

Transaction

Atomic unit of execution and data modification inside xGT, used to maintain data consistency under concurrency.

Union Subquery

A query sharing results with other subqueries. The results can be unique for all union subqueries or possibly repeated.

User Labels

Set of security labels attached to an authenticated user’s identity.