C++ library for HDTr

HDTr is an extension of HDT for reified triples.

Getting Started

Prerequisites

The implementation has the following dependencies:

• Serd v0.28+ This enables importing RDF data in the Turtle, N-Triples, and N-Quads serialization formats specifically. The dependency is activated by default.
• libz Enables loading RDF files compressed with GZIP (e.g., file.nq.gz) and gzipped HDTr files (file.hdtr.gz). The dependency is activated by default.
• Kyoto Cabinet (optional) Enables generating big RDF datasets on machines without much RAM memory, by creating a temporary Kyoto Cabinet database. The dependency is deactivated by default; to activate it, call configure with --with-kyoto=yes flag during installation.

The installation process has the following dependencies:

• autoconf
• libtool

The following commands should install both packages:

sudo apt-get update
sudo apt-get install autoconf libtool

Installing

To compile and install, run the following commands under the root directory hdtr-cpp. This will generate the library and tools.

First run the following script to generate all necessary installation files with autotools:

./autogen.sh

Then, run:

./configure
make -j2

Running

After building, these are the typical operations that you will perform (you need to change directory to libhdt first):

• Convert your n-quads to HDTr:

  NB: the input stream is assumed to be valid n-quads, so you should validate your data before feeding it into rdf2hdt.

  $ tools/rdf2hdt data/tests.nq data/tests.hdtr
  

• Create only the index of an HDTr file:

  $ tools/hdtSearch -q 0 data/tests.hdtr
  

• Open a terminal to search quad patterns within an HDTr file:

  $ tools/hdtSearch data/tests.hdtr
  
  >> ? ? ? http://example.org/G7
  http://example.org/C1 http://example.org/link1 http://example.org/G3 http://example.org/G7
  
  1 results in 71
  
  >> http://example.org/G7 ? ? ?
  http://example.org/G7 http://example.org/link4 http://example.org/O1
  http://example.org/G7 http://example.org/link6 http://example.org/G9
  http://example.org/G7 http://example.org/link6 http://example.org/G2
  http://example.org/G7 http://example.org/link6 http://example.org/G3
  
  4 results in 366
  
  >> exit