Esempio n. 1
0
        /// <summary>
        /// Applies the query to the given store
        /// </summary>
        public RDFDescribeQueryResult ApplyToStore(RDFStore store)
        {
            if (store != null)
            {
                this.PatternGroupResultTables.Clear();
                this.PatternResultTables.Clear();

                RDFDescribeQueryResult describeResult = new RDFDescribeQueryResult(this.ToString());
                if (!this.IsEmpty)
                {
                    //Iterate the pattern groups of the query
                    foreach (RDFPatternGroup patternGroup in this.PatternGroups)
                    {
                        //Step 1: Get the intermediate result tables of the current pattern group
                        RDFDescribeQueryEngine.EvaluatePatterns(this, patternGroup, store);

                        //Step 2: Get the result table of the current pattern group
                        RDFDescribeQueryEngine.CombinePatterns(this, patternGroup);

                        //Step 3: Apply the filters of the current pattern group to its result table
                        RDFDescribeQueryEngine.ApplyFilters(this, patternGroup);
                    }

                    //Step 4: Get the result table of the query
                    DataTable queryResultTable = RDFQueryEngine.CombineTables(this.PatternGroupResultTables.Values.ToList <DataTable>(), false);

                    //Step 5: Describe the terms from the result table
                    DataTable describeResultTable = RDFDescribeQueryEngine.DescribeTerms(this, store, queryResultTable);

                    //Step 6: Apply the modifiers of the query to the result table
                    describeResult.DescribeResults = RDFDescribeQueryEngine.ApplyModifiers(this, describeResultTable);
                }
                else
                {
                    //In this case the only chance to proceed is to have resources in the describe terms,
                    //which will be used to search for S-P-O data. Variables are omitted in this scenario.
                    if (this.DescribeTerms.Any(dt => dt is RDFResource))
                    {
                        //Step 1: Describe the terms from the result table
                        DataTable describeResultTable = RDFDescribeQueryEngine.DescribeTerms(this, store, new DataTable());

                        //Step 2: Apply the modifiers of the query to the result table
                        describeResult.DescribeResults = RDFDescribeQueryEngine.ApplyModifiers(this, describeResultTable);
                    }
                }

                return(describeResult);
            }
            throw new RDFQueryException("Cannot execute DESCRIBE query because given \"store\" parameter is null.");
        }
Esempio n. 2
0
        /// <summary>
        /// Applies the query to the given federation
        /// </summary>
        public RDFDescribeQueryResult ApplyToFederation(RDFFederation federation)
        {
            if (federation != null)
            {
                this.PatternGroupResultTables.Clear();
                this.PatternResultTables.Clear();

                RDFDescribeQueryResult describeResult = new RDFDescribeQueryResult(this.ToString());
                if (!this.IsEmpty)
                {
                    //Iterate the pattern groups of the query
                    var fedPatternResultTables = new Dictionary <RDFPatternGroup, List <DataTable> >();
                    foreach (RDFPatternGroup patternGroup in this.PatternGroups)
                    {
                        #region TrueFederations
                        foreach (RDFStore store in federation.Stores.Values)
                        {
                            //Step 1: Evaluate the patterns of the current pattern group on the current store
                            RDFDescribeQueryEngine.EvaluatePatterns(this, patternGroup, store);

                            //Step 2: Federate the patterns of the current pattern group on the current store
                            if (!fedPatternResultTables.ContainsKey(patternGroup))
                            {
                                fedPatternResultTables.Add(patternGroup, this.PatternResultTables[patternGroup]);
                            }
                            else
                            {
                                fedPatternResultTables[patternGroup].ForEach(fprt =>
                                                                             fprt.Merge(this.PatternResultTables[patternGroup].Single(prt => prt.TableName.Equals(fprt.TableName, StringComparison.Ordinal)), true, MissingSchemaAction.Add));
                            }
                        }
                        this.PatternResultTables[patternGroup] = fedPatternResultTables[patternGroup];
                        #endregion

                        //Step 3: Get the result table of the current pattern group
                        RDFDescribeQueryEngine.CombinePatterns(this, patternGroup);

                        //Step 4: Apply the filters of the current pattern group to its result table
                        RDFDescribeQueryEngine.ApplyFilters(this, patternGroup);
                    }

                    //Step 5: Get the result table of the query
                    DataTable queryResultTable = RDFQueryEngine.CombineTables(this.PatternGroupResultTables.Values.ToList <DataTable>(), false);

                    //Step 6: Describe the terms on each store and merge them in the federated result table
                    DataTable describeResultTable = new DataTable(this.ToString());
                    foreach (RDFStore store in federation.Stores.Values)
                    {
                        describeResultTable.Merge(RDFDescribeQueryEngine.DescribeTerms(this, store, queryResultTable), true, MissingSchemaAction.Add);
                    }

                    //Step 7: Apply the modifiers of the query to the result table
                    describeResult.DescribeResults = RDFDescribeQueryEngine.ApplyModifiers(this, describeResultTable);
                }
                else
                {
                    //In this case the only chance to proceed is to have resources in the describe terms,
                    //which will be used to search for S-P-O data. Variables are ignored in this scenario.
                    if (this.DescribeTerms.Any(dt => dt is RDFResource))
                    {
                        //Step 1: Describe the terms on each store and merge them in the federated result table
                        DataTable describeResultTable = new DataTable(this.ToString());
                        foreach (RDFStore store in federation.Stores.Values)
                        {
                            describeResultTable.Merge(RDFDescribeQueryEngine.DescribeTerms(this, store, new DataTable()), true, MissingSchemaAction.Add);
                        }

                        //Step 2: Apply the modifiers of the query to the result table
                        describeResult.DescribeResults = RDFDescribeQueryEngine.ApplyModifiers(this, describeResultTable);
                    }
                }

                return(describeResult);
            }
            throw new RDFQueryException("Cannot execute DESCRIBE query because given \"federation\" parameter is null.");
        }