Drewer

A query answering system for existential rules via datalog rewriting

Overview

Drewer is a query ansewring system for existential rules based on efficient datalog rewriting.
For the solving of datalog program, Drewer integrates VLog as its datalog engine.

Drewer accepts ontoglogy files in DLGP format, which is a format designed for existential rules and used in the Graal system.
To obtain a DLGP file from OWL file, one can use the transformation tool provided by Graal.
The current version of Drewer does not support constraints.

Data files must be in the CSV format to be loaded by VLog. Drewer supports conjunctive queries, which must also be in DLGP format.

Downloads

The system executables and benchmarks for our system evaluations are included in this zip file.

Usage

1. Query rewriting:
Drewer can perform datalog rewriting for existential rules and output the results in the DLGP format.
java -jar drewer.jar -o [ONTOLOGY_FILE] -q [QUERY_FILE]
ONTOLOGY_FILE is a ontology file in the DLGP format, e.g., LUBM.dlp QUERY_FILE is a query file in the DLGP format, e.g., queries.dlp
2. Query answering:
java -jar drewer.jar -o [ONTOLOGY_FILE] -q [QUERY_FILE] -d [DATA_DIR]
DATA_DIR is the directory containing the data files in the CSV format
3. Fus-shyness and weakly-acyclicity checking:
In our package, a checker to check fus-shyness for ontologies is provided.
java -jar checker.jar [ONTOLOGY_FILE]

Publications

[1] Zhe Wang, Peng Xiao, Kewen Wang, Zhiqiang Zhuang, and Hai Wan. Query Answering for Existential Rules vis Efficient Datalog Rewriting. IJCAI 2020