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TQL User Guide

TQL is an interpreted command and query language useful for managing a Mulgara server. It provides a higher-level interface for executing commands than that of the Connection API, although the two interfaces expose roughly the same features. There are several methods of executing TQL commands (these are listed in descending order from highest to lowest-level API):

  • The Web User Interface
    • when using cURL or a similar command-line tool, using a header "Accept: application/sparql-results+json" will usually produce more readable results
    • omit the "Content-Type" header
  • Using the interactive iTQL shell (this is useful for general development and debugging purposes).
  • A series of TQL commands may be collected into a script file and run as a batch process.
  • The ItqlInterpreterBean interface provides a Java API for automatically parsing and executing TQL commands.
  • The TqlInterpreter interface may be used to parse TQL commands into a Command object, which may then be executed via the Connection API. This requires the most coding, but also gives the greatest control over the process.

TQL Features

The following is a list of query and management capabilities provided by TQL:

  • Alias - Create and view namespace aliases.
  • BackupRestore - Back up and restore the entire contents of a Mulgara server.
  • Comment(#) - Comments in the language.
  • Commit - Commits modifications in a transaction.
  • Create - Create a new graph.
  • Delete - Deletes statements from a graph.
  • Drop - Removes a graph.
  • Execute - Run a script.
  • ExportLoad - Move data into (load) and out of (export) a graph stored on a Mulgara server, to and from external RDF files.
  • Help - Get help on using commands.
  • Insert - Inserts statements into a graph.
  • Quit - Exits an interactive shell.
  • Rollback - Abandons modifications in a transaction.
  • Select - Queries data.
  • Set - Sets internal state, such as transaction state.
    Note: Prior to Mulgara 2.0, the backup command was overloaded to back up individual graphs as well as the entire server. In the latest version, the feature to back up an individual graph has been moved to the export command.