Getting Started

MillenniumDB currently supports two database models:

  • RDF, which can be queried using SPARQL

  • Quad, which can be queried using MQL

In this document we will describe how to get up and running using mdb cli.

For instructions on how to use the client-server model check out Client-Server after reading Creating a Database.

Creating a Database

To create a database you need a data-file.

Todo

Describe and link to .qm format.

  • For a Quad database the data-file should have a .qm extension.

  • For a RDF database the file should be in the Turtle format and have a .ttl extension.

To import data from a data-file and create a database use the mdb import command:

mdb import <data-file> <db-directory>

  • <data-file> is the path to the file containing the data to import.

  • <db-directory> is the path of the directory where the new database will be created.

Tip

If your data-file does not have a matching extension and you do not want to change the extension you can pass the explicit -m,--model option with quad or rdf:

mdb import -m <model> <data-file> <db-directory>

Prefix Definitions (Optional)

Using a prefixes-file is optional, but helps reduce the space occupied by IRIs in the database. MillenniumDB generates an OID for each prefix, and when importing IRIs into the database replaces any prefixes with IDs. For large databases this can save a significant amount of space.

The prefixes-file should contain one prefix per line, with each line consisting of a prefix alias and the prefix itself:

http://www.myprefix.com/
https://other.prefix.com/foo
https://other.prefix.com/bar

To use a prefixes-file you can pass it to the mdb import command using the --prefixes options:

mdb import --prefixes <prefixes-file> <data-file> <db-directory>

Using the Interactive CLI

After creating a database you can use the interactive CLI interface.

All you need to do is launch mdb cli, passing it the database, as follow:

mdb cli <db-directory>

The database model is detected automatically. Upon launching the CLI it will show a message with instructions. Depending on the database model you can start executing SPARQL or MQL queries.

Removing a Database

To remove a database simply delete the directory:

rm -r <db-directory>