It's difficult to extract sense from strings, but they're the only communication coin we can count on.
Alan Perlis, Epigrams in Programming
Stardog Terminology
In the Stardog documentation, the following terms have a specific technical meaning.
- Stardog Database Management System, aka Stardog Server, aka Stardog
- An instance of Stardog: only one Stardog Server may run per
JVM. A computer may run multiple Stardog Servers
by running one per multiple JVMs.
- Stardog Home, aka STARDOG_HOME
- A directory in a filesystem in which Stardog stores files and
other information; established either in a Stardog configuration file or by
environment variable. Only one Stardog Server may run simultaneously from a STARDOG_HOME.
- Stardog Network Home
- A URL (HTTP or SNARL) which identifies a
Stardog Server running on the network.
- Database
- A Stardog database is a graph of RDF data under management of a
Stardog Server. It may contain zero or more RDF Named Graphs. A Stardog Server may manage
more than one Database; there is no hard limit, and the practical limit is
disk space.
- Database Short Name, aka Database Name
- An identifier used to name a database, provided as input when a
database is created.
- Database Network Name
- A Database Short Name is part of the URI of a Database addressed
over some network protocol.
- Index
- The unit of persistence for a Database. We sometimes (sloppily) use Database and Index interchangeably in the Stardog docs.
- Memory Database
- A Database may be stored in-memory or on disk; a Memory Database is read entirely into system memory but can be (optionally) persisted to disk.
- Disk Database
- A Disk Database is only paged into system memory as needed and is persisted using one or more indexes.
- Connection String
- An identifier (a restricted subset of legal URLs, actually) that is used to connect to a Stardog database to send queries or perform other operations.
- Named Graph
- A Named Graph is an explicitly named unit of data within a
Database. Named Graphs are queries explicitly by specifying them in SPARQL
queries. There is no practical limit on the number of Named Graphs in a
Database.
- Default Graph
- The Default Graph in a Database is the context into which RDF
triples are stored when a Named Graph is not explicitly specified. A SPARQL
query executed by Stardog that does not contain any Named Graph statements
is executed against the data in the Default Graph only.
- Security Realm
- A Security Realm defines the users and their permissions for each Database in an Stardog Server. There is only one Security Realm per Stardog Server.
