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RDFQueryEngine.cs
1158 lines (1072 loc) · 74.9 KB
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RDFQueryEngine.cs
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/*
Copyright 2012-2016 Marco De Salvo
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using RDFSharp.Model;
using RDFSharp.Store;
namespace RDFSharp.Query
{
/// <summary>
/// RDFQueryEngine is the MIRELLA SPARQL engine for construction and execution of SPARQL queries.
/// </summary>
internal static class RDFQueryEngine {
#region Properties
/// <summary>
/// Static instance of the comparer used by the engine to compare data columns
/// </summary>
internal static readonly DataColumnComparer dtComparer = new DataColumnComparer();
#endregion
#region Methods
/// <summary>
/// Joins two datatables WITHOUT support for OPTIONAL data
/// </summary>
internal static DataTable InnerJoinTables(DataTable dt1, DataTable dt2) {
DataTable result = new DataTable();
IEnumerable<DataColumn> dt1Cols = dt1.Columns.OfType<DataColumn>();
IEnumerable<DataColumn> dt2Cols = dt2.Columns.OfType<DataColumn>();
//To avoid possibility of multiple enumerations of IEnumerable
IEnumerable<DataColumn> dt1Columns = (dt1Cols as IList<DataColumn> ?? dt1Cols.ToList<DataColumn>());
IEnumerable<DataColumn> dt2Columns = (dt2Cols as IList<DataColumn> ?? dt2Cols.ToList<DataColumn>());
//Determine common columns
DataColumn[] commonColumns = dt1Columns.Intersect(dt2Columns, RDFQueryEngine.dtComparer)
.Select(c => new DataColumn(c.Caption, c.DataType))
.ToArray();
//PRODUCT-JOIN
if (commonColumns.Length == 0) {
//Create the structure of the product table
result.Columns.AddRange(dt1Columns.Union(dt2Columns, RDFQueryEngine.dtComparer)
.Select(c => new DataColumn(c.Caption, c.DataType))
.ToArray());
//Loop through dt1 table
result.AcceptChanges();
result.BeginLoadData();
foreach (DataRow parentRow in dt1.Rows) {
Object[] firstArray = parentRow.ItemArray;
//Loop through dt2 table
foreach (DataRow childRow in dt2.Rows) {
Object[] secondArray = childRow.ItemArray;
Object[] productArray = new Object[firstArray.Length + secondArray.Length];
Array.Copy(firstArray, 0, productArray, 0, firstArray.Length);
Array.Copy(secondArray, 0, productArray, firstArray.Length, secondArray.Length);
result.LoadDataRow(productArray, true);
}
}
result.EndLoadData();
}
//INNER-JOIN
else {
//Use a DataSet to leverage a relation linking the common columns
using (DataSet ds = new DataSet()) {
//Add copy of the tables to the dataset
ds.Tables.AddRange(new DataTable[] { dt1, dt2 });
//Identify join columns from dt1
DataColumn[] parentColumns = new DataColumn[commonColumns.Length];
for (Int32 i = 0; i < parentColumns.Length; i++) {
parentColumns[i] = ds.Tables[0].Columns[commonColumns[i].ColumnName];
}
//Identify join columns from dt2
DataColumn[] childColumns = new DataColumn[commonColumns.Length];
for (Int32 i = 0; i < childColumns.Length; i++) {
childColumns[i] = ds.Tables[1].Columns[commonColumns[i].ColumnName];
}
//Create the relation linking the common columns
DataRelation r = new DataRelation("JoinRelation", parentColumns, childColumns, false);
ds.Relations.Add(r);
//Create the structure of the join table
List<String> duplicatedCols = new List<String>();
for (Int32 i = 0; i < ds.Tables[0].Columns.Count; i++) {
result.Columns.Add(ds.Tables[0].Columns[i].ColumnName, ds.Tables[0].Columns[i].DataType);
}
for (Int32 i = 0; i < ds.Tables[1].Columns.Count; i++) {
if (!result.Columns.Contains(ds.Tables[1].Columns[i].ColumnName)) {
result.Columns.Add(ds.Tables[1].Columns[i].ColumnName, ds.Tables[1].Columns[i].DataType);
}
else {
//Manage duplicated columns by appending a know identificator to their name
result.Columns.Add(ds.Tables[1].Columns[i].ColumnName + "_DUPLICATE_", ds.Tables[1].Columns[i].DataType);
duplicatedCols.Add(ds.Tables[1].Columns[i].ColumnName + "_DUPLICATE_");
}
}
//Loop through dt1 table
result.AcceptChanges();
result.BeginLoadData();
foreach (DataRow firstRow in ds.Tables[0].Rows) {
//Get "joined" dt2 rows by exploiting the leveraged relation
DataRow[] childRows = firstRow.GetChildRows(r);
if (childRows.Length > 0) {
Object[] parentArray = firstRow.ItemArray;
foreach (DataRow secondRow in childRows) {
Object[] secondArray = secondRow.ItemArray;
Object[] joinArray = new Object[parentArray.Length + secondArray.Length];
Array.Copy(parentArray, 0, joinArray, 0, parentArray.Length);
Array.Copy(secondArray, 0, joinArray, parentArray.Length, secondArray.Length);
result.LoadDataRow(joinArray, true);
}
}
}
//Eliminate the duplicated columns from the result table
duplicatedCols.ForEach(c => result.Columns.Remove(c));
result.EndLoadData();
}
}
return result;
}
/// <summary>
/// Joins two datatables WITH support for OPTIONAL data
/// </summary>
internal static DataTable OuterJoinTables(DataTable dt1, DataTable dt2) {
DataTable finalResult = new DataTable();
IEnumerable<DataColumn> dt1Cols = dt1.Columns.OfType<DataColumn>();
IEnumerable<DataColumn> dt2Cols = dt2.Columns.OfType<DataColumn>();
//To avoid possibility of multiple enumerations of IEnumerable
IEnumerable<DataColumn> dt1Columns = (dt1Cols as IList<DataColumn> ?? dt1Cols.ToList<DataColumn>());
IEnumerable<DataColumn> dt2Columns = (dt2Cols as IList<DataColumn> ?? dt2Cols.ToList<DataColumn>());
Boolean dt2IsOptionalTable = (dt2.ExtendedProperties.ContainsKey("IsOptional") && dt2.ExtendedProperties["IsOptional"].Equals(true));
Boolean joinInvalidationFlag = false;
Boolean foundAnyResult = false;
String strResCol = String.Empty;
//Step 1: Determine common columns
DataColumn[] commonColumns = dt1Columns.Intersect(dt2Columns, RDFQueryEngine.dtComparer)
.Select(c => new DataColumn(c.Caption, c.DataType))
.ToArray();
//Step 2: Create structure of finalResult table
finalResult.Columns.AddRange(dt1Columns.Union(dt2Columns.Except(commonColumns), RDFQueryEngine.dtComparer)
.Select(c => new DataColumn(c.Caption, c.DataType))
.ToArray());
//Step 3: Loop through dt1 table
finalResult.AcceptChanges();
finalResult.BeginLoadData();
foreach (DataRow leftRow in dt1.Rows) {
foundAnyResult = false;
//Step 4: Loop through dt2 table
foreach (DataRow rightRow in dt2.Rows) {
joinInvalidationFlag = false;
//Step 5: Create a temporary join row
DataRow joinRow = finalResult.NewRow();
foreach (DataColumn resCol in finalResult.Columns) {
if (!joinInvalidationFlag) {
strResCol = resCol.ToString();
//Step 6a: NON-COMMON column
if (!commonColumns.Any(col => col.ToString().Equals(strResCol, StringComparison.Ordinal))) {
//Take value from left
if (dt1Columns.Any(col => col.ToString().Equals(strResCol, StringComparison.Ordinal))) {
joinRow[strResCol] = leftRow[strResCol];
}
//Take value from right
else {
joinRow[strResCol] = rightRow[strResCol];
}
}
//Step 6b: COMMON column
else {
//Left value is NULL
if (leftRow.IsNull(strResCol)) {
//Right value is NULL
if (rightRow.IsNull(strResCol)) {
//Take NULL value
joinRow[strResCol] = DBNull.Value;
}
//Right value is NOT NULL
else {
//Take value from right
joinRow[strResCol] = rightRow[strResCol];
}
}
//Left value is NOT NULL
else {
//Right value is NULL
if (rightRow.IsNull(strResCol)) {
//Take value from left
joinRow[strResCol] = leftRow[strResCol];
}
//Right value is NOT NULL
else {
//Left value is EQUAL TO right value
if (leftRow[strResCol].ToString().Equals(rightRow[strResCol].ToString(), StringComparison.Ordinal)) {
//Take value from left (it's the same)
joinRow[strResCol] = leftRow[strResCol];
}
//Left value is NOT EQUAL TO right value
else {
//Raise the join invalidation flag
joinInvalidationFlag = true;
//Reject changes on the join row
joinRow.RejectChanges();
}
}
}
}
}
}
//Step 7: Add join row to finalResults table
if (!joinInvalidationFlag) {
joinRow.AcceptChanges();
finalResult.Rows.Add(joinRow);
foundAnyResult = true;
}
}
//Step 8: Manage presence of "OPTIONAL" pattern to the right
if (!foundAnyResult && dt2IsOptionalTable) {
//In this case, the left row must be kept anyway and other columns from right are NULL
DataRow optionalRow = finalResult.NewRow();
optionalRow.ItemArray = leftRow.ItemArray;
optionalRow.AcceptChanges();
finalResult.Rows.Add(optionalRow);
}
}
finalResult.EndLoadData();
return finalResult;
}
/// <summary>
/// Merges / Joins / Products the given list of data tables, based on presence of common columns and dynamic detection of Optional / Union operators
/// </summary>
internal static DataTable CombineTables(List<DataTable> dataTables, Boolean isMerge) {
DataTable finalTable = new DataTable();
Boolean switchToOuterJoin = false;
if (dataTables.Count > 0) {
//Process Unions
for (Int32 i = 1; i < dataTables.Count; i++) {
if (isMerge || (dataTables[i - 1].ExtendedProperties.ContainsKey("JoinAsUnion") && dataTables[i - 1].ExtendedProperties["JoinAsUnion"].Equals(true))) {
//Merge the previous table into the current one
dataTables[i].Merge(dataTables[i - 1], true, MissingSchemaAction.Add);
//Clear the previous table and flag it as logically deleted
dataTables[i - 1].Rows.Clear();
dataTables[i - 1].ExtendedProperties.Add("LogicallyDeleted", true);
//Set automatic switch to OuterJoin (because we have done Unions, so null values must be preserved)
switchToOuterJoin = true;
}
}
dataTables.RemoveAll(dt => dt.ExtendedProperties.ContainsKey("LogicallyDeleted") && dt.ExtendedProperties["LogicallyDeleted"].Equals(true));
//Process Joins
finalTable = dataTables[0];
for (Int32 i = 1; i < dataTables.Count; i++) {
//Set automatic switch to OuterJoin in case of relevant "Optional" detected
switchToOuterJoin = (switchToOuterJoin || (dataTables[i].ExtendedProperties.ContainsKey("IsOptional") && dataTables[i].ExtendedProperties["IsOptional"].Equals(true)));
//Support OPTIONAL data
if (switchToOuterJoin) {
finalTable = RDFQueryEngine.OuterJoinTables(finalTable, dataTables[i]);
}
//Do not support OPTIONAL data
else {
finalTable = RDFQueryEngine.InnerJoinTables(finalTable, dataTables[i]);
}
}
}
return finalTable;
}
/// <summary>
/// Applies the given pattern to the given graph
/// </summary>
internal static DataTable ApplyPattern(RDFPattern pattern, RDFGraph graph) {
var matchingTriples = new List<RDFTriple>();
var resultTable = new DataTable();
//Apply the right pattern to the graph
if (pattern.Subject is RDFResource) {
if (pattern.Predicate is RDFResource) {
//S->P->
matchingTriples = RDFModelUtilities.SelectTriples(graph, (RDFResource)pattern.Subject,
(RDFResource)pattern.Predicate,
null,
null);
RDFQueryUtilities.AddColumn(resultTable, pattern.Object.ToString());
RDFQueryEngine.PopulateTable(pattern, matchingTriples, RDFQueryEnums.RDFPatternHoles.O, resultTable);
}
else {
if (pattern.Object is RDFResource || pattern.Object is RDFLiteral) {
if (pattern.Object is RDFResource) {
//S->->O
matchingTriples = RDFModelUtilities.SelectTriples(graph, (RDFResource)pattern.Subject,
null,
(RDFResource)pattern.Object,
null);
}
else {
//S->->L
matchingTriples = RDFModelUtilities.SelectTriples(graph, (RDFResource)pattern.Subject,
null,
null,
(RDFLiteral)pattern.Object);
}
RDFQueryUtilities.AddColumn(resultTable, pattern.Predicate.ToString());
RDFQueryEngine.PopulateTable(pattern, matchingTriples, RDFQueryEnums.RDFPatternHoles.P, resultTable);
}
else {
//S->->
matchingTriples = RDFModelUtilities.SelectTriples(graph, (RDFResource)pattern.Subject,
null,
null,
null);
//In case of same P and O variable, must refine matching triples with a further value comparison
if (pattern.Predicate.Equals(pattern.Object)) {
matchingTriples = matchingTriples.FindAll(mt => mt.Predicate.Equals(mt.Object));
}
RDFQueryUtilities.AddColumn(resultTable, pattern.Predicate.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Object.ToString());
RDFQueryEngine.PopulateTable(pattern, matchingTriples, RDFQueryEnums.RDFPatternHoles.PO, resultTable);
}
}
}
else {
if (pattern.Predicate is RDFResource) {
if (pattern.Object is RDFResource || pattern.Object is RDFLiteral) {
if (pattern.Object is RDFResource) {
//->P->O
matchingTriples = RDFModelUtilities.SelectTriples(graph, null,
(RDFResource)pattern.Predicate,
(RDFResource)pattern.Object,
null);
}
else {
//->P->L
matchingTriples = RDFModelUtilities.SelectTriples(graph, null,
(RDFResource)pattern.Predicate,
null,
(RDFLiteral)pattern.Object);
}
RDFQueryUtilities.AddColumn(resultTable, pattern.Subject.ToString());
RDFQueryEngine.PopulateTable(pattern, matchingTriples, RDFQueryEnums.RDFPatternHoles.S, resultTable);
}
else {
//->P->
matchingTriples = RDFModelUtilities.SelectTriples(graph, null,
(RDFResource)pattern.Predicate,
null,
null);
//In case of same S and O variable, must refine matching triples with a further value comparison
if (pattern.Subject.Equals(pattern.Object)) {
matchingTriples = matchingTriples.FindAll(mt => mt.Subject.Equals(mt.Object));
}
RDFQueryUtilities.AddColumn(resultTable, pattern.Subject.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Object.ToString());
RDFQueryEngine.PopulateTable(pattern, matchingTriples, RDFQueryEnums.RDFPatternHoles.SO, resultTable);
}
}
else {
if (pattern.Object is RDFResource || pattern.Object is RDFLiteral) {
if (pattern.Object is RDFResource) {
matchingTriples = RDFModelUtilities.SelectTriples(graph, null,
null,
(RDFResource)pattern.Object,
null);
}
else {
//->->L
matchingTriples = RDFModelUtilities.SelectTriples(graph, null,
null,
null,
(RDFLiteral)pattern.Object);
}
//In case of same S and P variable, must refine matching triples with a further value comparison
if (pattern.Subject.Equals(pattern.Predicate)) {
matchingTriples = matchingTriples.FindAll(mt => mt.Subject.Equals(mt.Predicate));
}
RDFQueryUtilities.AddColumn(resultTable, pattern.Subject.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Predicate.ToString());
RDFQueryEngine.PopulateTable(pattern, matchingTriples, RDFQueryEnums.RDFPatternHoles.SP, resultTable);
}
else {
//->->
matchingTriples = RDFModelUtilities.SelectTriples(graph, null,
null,
null,
null);
//In case of same S and P variable, must refine matching triples with a further value comparison
if (pattern.Subject.Equals(pattern.Predicate)) {
matchingTriples = matchingTriples.FindAll(mt => mt.Subject.Equals(mt.Predicate));
}
//In case of same S and O variable, must refine matching triples with a further value comparison
if (pattern.Subject.Equals(pattern.Object)) {
matchingTriples = matchingTriples.FindAll(mt => mt.Subject.Equals(mt.Object));
}
//In case of same P and O variable, must refine matching triples with a further value comparison
if (pattern.Predicate.Equals(pattern.Object)) {
matchingTriples = matchingTriples.FindAll(mt => mt.Predicate.Equals(mt.Object));
}
RDFQueryUtilities.AddColumn(resultTable, pattern.Subject.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Predicate.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Object.ToString());
RDFQueryEngine.PopulateTable(pattern, matchingTriples, RDFQueryEnums.RDFPatternHoles.SPO, resultTable);
}
}
}
return resultTable;
}
/// <summary>
/// Applies the given pattern to the given store
/// </summary>
internal static DataTable ApplyPattern(RDFPattern pattern, RDFStore store) {
RDFMemoryStore result = new RDFMemoryStore();
DataTable resultTable = new DataTable();
//CSPO pattern
if (pattern.Context != null) {
if (pattern.Context is RDFContext) {
if (pattern.Subject is RDFResource) {
if (pattern.Predicate is RDFResource) {
//C->S->P->
result = store.SelectQuadruples((RDFContext)pattern.Context,
(RDFResource)pattern.Subject,
(RDFResource)pattern.Predicate,
null,
null);
RDFQueryUtilities.AddColumn(resultTable, pattern.Object.ToString());
RDFQueryEngine.PopulateTable(pattern, result, RDFQueryEnums.RDFPatternHoles.O, resultTable);
}
else {
if (pattern.Object is RDFResource || pattern.Object is RDFLiteral) {
//C->S->->O
if (pattern.Object is RDFResource) {
result = store.SelectQuadruples((RDFContext)pattern.Context,
(RDFResource)pattern.Subject,
null,
(RDFResource)pattern.Object,
null);
}
//C->S->->L
else {
result = store.SelectQuadruples((RDFContext)pattern.Context,
(RDFResource)pattern.Subject,
null,
null,
(RDFLiteral)pattern.Object);
}
RDFQueryUtilities.AddColumn(resultTable, pattern.Predicate.ToString());
RDFQueryEngine.PopulateTable(pattern, result, RDFQueryEnums.RDFPatternHoles.P, resultTable);
}
else {
//C->S->->
result = store.SelectQuadruples((RDFContext)pattern.Context,
(RDFResource)pattern.Subject,
null,
null,
null);
//In case of same P and O variable, must refine matching quadruples with a further value comparison
if (pattern.Predicate.Equals(pattern.Object)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Predicate.Equals(mt.Object)).ToList<RDFQuadruple>());
}
RDFQueryUtilities.AddColumn(resultTable, pattern.Predicate.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Object.ToString());
RDFQueryEngine.PopulateTable(pattern, result, RDFQueryEnums.RDFPatternHoles.PO, resultTable);
}
}
}
else {
if (pattern.Predicate is RDFResource) {
if (pattern.Object is RDFResource || pattern.Object is RDFLiteral) {
//C->->P->O
if (pattern.Object is RDFResource) {
result = store.SelectQuadruples((RDFContext)pattern.Context,
null,
(RDFResource)pattern.Predicate,
(RDFResource)pattern.Object,
null);
}
//C->->P->L
else {
result = store.SelectQuadruples((RDFContext)pattern.Context,
null,
(RDFResource)pattern.Predicate,
null,
(RDFLiteral)pattern.Object);
}
RDFQueryUtilities.AddColumn(resultTable, pattern.Subject.ToString());
RDFQueryEngine.PopulateTable(pattern, result, RDFQueryEnums.RDFPatternHoles.S, resultTable);
}
else {
//C->->P->
result = store.SelectQuadruples((RDFContext)pattern.Context,
null,
(RDFResource)pattern.Predicate,
null,
null);
//In case of same S and O variable, must refine matching quadruples with a further value comparison
if (pattern.Subject.Equals(pattern.Object)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Subject.Equals(mt.Object)).ToList<RDFQuadruple>());
}
RDFQueryUtilities.AddColumn(resultTable, pattern.Subject.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Object.ToString());
RDFQueryEngine.PopulateTable(pattern, result, RDFQueryEnums.RDFPatternHoles.SO, resultTable);
}
}
else {
if (pattern.Object is RDFResource || pattern.Object is RDFLiteral) {
//C->->->O
if (pattern.Object is RDFResource) {
result = store.SelectQuadruples((RDFContext)pattern.Context,
null,
null,
(RDFResource)pattern.Object,
null);
}
//C->->->L
else {
result = store.SelectQuadruples((RDFContext)pattern.Context,
null,
null,
null,
(RDFLiteral)pattern.Object);
}
//In case of same S and P variable, must refine matching quadruples with a further value comparison
if (pattern.Subject.Equals(pattern.Predicate)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Subject.Equals(mt.Predicate)).ToList<RDFQuadruple>());
}
RDFQueryUtilities.AddColumn(resultTable, pattern.Subject.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Predicate.ToString());
RDFQueryEngine.PopulateTable(pattern, result, RDFQueryEnums.RDFPatternHoles.SP, resultTable);
}
else {
//C->->->
result = store.SelectQuadruples((RDFContext)pattern.Context,
null,
null,
null,
null);
//In case of same S and P variable, must refine matching quadruples with a further value comparison
if (pattern.Subject.Equals(pattern.Predicate)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Subject.Equals(mt.Predicate)).ToList<RDFQuadruple>());
}
//In case of same S and O variable, must refine matching quadruples with a further value comparison
if (pattern.Subject.Equals(pattern.Object)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Subject.Equals(mt.Object)).ToList<RDFQuadruple>());
}
//In case of same P and O variable, must refine matching quadruples with a further value comparison
if (pattern.Predicate.Equals(pattern.Object)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Predicate.Equals(mt.Object)).ToList<RDFQuadruple>());
}
RDFQueryUtilities.AddColumn(resultTable, pattern.Subject.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Predicate.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Object.ToString());
RDFQueryEngine.PopulateTable(pattern, result, RDFQueryEnums.RDFPatternHoles.SPO, resultTable);
}
}
}
}
else {
if (pattern.Subject is RDFResource) {
if (pattern.Predicate is RDFResource) {
if (pattern.Object is RDFResource || pattern.Object is RDFLiteral) {
//->S->P->O
if (pattern.Object is RDFResource) {
result = store.SelectQuadruples(null,
(RDFResource)pattern.Subject,
(RDFResource)pattern.Predicate,
(RDFResource)pattern.Object,
null);
}
//->S->P->L
else {
result = store.SelectQuadruples(null,
(RDFResource)pattern.Subject,
(RDFResource)pattern.Predicate,
null,
(RDFLiteral)pattern.Object);
}
RDFQueryUtilities.AddColumn(resultTable, pattern.Context.ToString());
RDFQueryEngine.PopulateTable(pattern, result, RDFQueryEnums.RDFPatternHoles.C, resultTable);
}
else {
//->S->P->
result = store.SelectQuadruples(null,
(RDFResource)pattern.Subject,
(RDFResource)pattern.Predicate,
null,
null);
//In case of same C and O variable, must refine matching quadruples with a further value comparison
if (pattern.Context.Equals(pattern.Object)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Context.Equals(mt.Object)).ToList<RDFQuadruple>());
}
RDFQueryUtilities.AddColumn(resultTable, pattern.Context.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Object.ToString());
RDFQueryEngine.PopulateTable(pattern, result, RDFQueryEnums.RDFPatternHoles.CO, resultTable);
}
}
else {
if (pattern.Object is RDFResource || pattern.Object is RDFLiteral) {
//->S->->O
if (pattern.Object is RDFResource) {
result = store.SelectQuadruples(null,
(RDFResource)pattern.Subject,
null,
(RDFResource)pattern.Object,
null);
}
//->S->->L
else {
result = store.SelectQuadruples(null,
(RDFResource)pattern.Subject,
null,
null,
(RDFLiteral)pattern.Object);
}
//In case of same C and P variable, must refine matching quadruples with a further value comparison
if (pattern.Context.Equals(pattern.Predicate)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Context.Equals(mt.Predicate)).ToList<RDFQuadruple>());
}
RDFQueryUtilities.AddColumn(resultTable, pattern.Context.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Predicate.ToString());
RDFQueryEngine.PopulateTable(pattern, result, RDFQueryEnums.RDFPatternHoles.CP, resultTable);
}
else {
//->S->->
result = store.SelectQuadruples(null,
(RDFResource)pattern.Subject,
null,
null,
null);
//In case of same C and P variable, must refine matching quadruples with a further value comparison
if (pattern.Context.Equals(pattern.Predicate)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Context.Equals(mt.Predicate)).ToList<RDFQuadruple>());
}
//In case of same C and O variable, must refine matching quadruples with a further value comparison
if (pattern.Context.Equals(pattern.Object)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Context.Equals(mt.Object)).ToList<RDFQuadruple>());
}
//In case of same P and O variable, must refine matching quadruples with a further value comparison
if (pattern.Predicate.Equals(pattern.Object)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Predicate.Equals(mt.Object)).ToList<RDFQuadruple>());
}
RDFQueryUtilities.AddColumn(resultTable, pattern.Context.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Predicate.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Object.ToString());
RDFQueryEngine.PopulateTable(pattern, result, RDFQueryEnums.RDFPatternHoles.CPO, resultTable);
}
}
}
else {
if (pattern.Predicate is RDFResource) {
if (pattern.Object is RDFResource || pattern.Object is RDFLiteral) {
//->->P->O
if (pattern.Object is RDFResource) {
result = store.SelectQuadruples(null,
null,
(RDFResource)pattern.Predicate,
(RDFResource)pattern.Object,
null);
}
//->->P->L
else {
result = store.SelectQuadruples(null,
null,
(RDFResource)pattern.Predicate,
null,
(RDFLiteral)pattern.Object);
}
//In case of same C and S variable, must refine matching quadruples with a further value comparison
if (pattern.Context.Equals(pattern.Subject)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Context.Equals(mt.Subject)).ToList<RDFQuadruple>());
}
RDFQueryUtilities.AddColumn(resultTable, pattern.Context.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Subject.ToString());
RDFQueryEngine.PopulateTable(pattern, result, RDFQueryEnums.RDFPatternHoles.CS, resultTable);
}
else {
//->->P->
result = store.SelectQuadruples(null,
null,
(RDFResource)pattern.Predicate,
null,
null);
//In case of same C and S variable, must refine matching quadruples with a further value comparison
if (pattern.Context.Equals(pattern.Subject)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Context.Equals(mt.Subject)).ToList<RDFQuadruple>());
}
//In case of same C and O variable, must refine matching quadruples with a further value comparison
if (pattern.Context.Equals(pattern.Object)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Context.Equals(mt.Object)).ToList<RDFQuadruple>());
}
//In case of same S and O variable, must refine matching quadruples with a further value comparison
if (pattern.Subject.Equals(pattern.Object)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Subject.Equals(mt.Object)).ToList<RDFQuadruple>());
}
RDFQueryUtilities.AddColumn(resultTable, pattern.Context.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Subject.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Object.ToString());
RDFQueryEngine.PopulateTable(pattern, result, RDFQueryEnums.RDFPatternHoles.CSO, resultTable);
}
}
else {
if (pattern.Object is RDFResource || pattern.Object is RDFLiteral) {
//->->->O
if (pattern.Object is RDFResource) {
result = store.SelectQuadruples(null,
null,
null,
(RDFResource)pattern.Object,
null);
}
//->->->L
else {
result = store.SelectQuadruples(null,
null,
null,
null,
(RDFLiteral)pattern.Object);
}
//In case of same C and S variable, must refine matching quadruples with a further value comparison
if (pattern.Context.Equals(pattern.Subject)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Context.Equals(mt.Subject)).ToList<RDFQuadruple>());
}
//In case of same C and P variable, must refine matching quadruples with a further value comparison
if (pattern.Context.Equals(pattern.Predicate)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Context.Equals(mt.Predicate)).ToList<RDFQuadruple>());
}
//In case of same S and P variable, must refine matching quadruples with a further value comparison
if (pattern.Subject.Equals(pattern.Predicate)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Subject.Equals(mt.Predicate)).ToList<RDFQuadruple>());
}
RDFQueryUtilities.AddColumn(resultTable, pattern.Context.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Subject.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Predicate.ToString());
RDFQueryEngine.PopulateTable(pattern, result, RDFQueryEnums.RDFPatternHoles.CSP, resultTable);
}
else {
//->->->
result = store.SelectQuadruples(null,
null,
null,
null,
null);
//In case of same C and S variable, must refine matching quadruples with a further value comparison
if (pattern.Context.Equals(pattern.Subject)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Context.Equals(mt.Subject)).ToList<RDFQuadruple>());
}
//In case of same C and P variable, must refine matching quadruples with a further value comparison
if (pattern.Context.Equals(pattern.Predicate)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Context.Equals(mt.Predicate)).ToList<RDFQuadruple>());
}
//In case of same C and O variable, must refine matching quadruples with a further value comparison
if (pattern.Context.Equals(pattern.Object)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Context.Equals(mt.Object)).ToList<RDFQuadruple>());
}
//In case of same S and P variable, must refine matching quadruples with a further value comparison
if (pattern.Subject.Equals(pattern.Predicate)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Subject.Equals(mt.Predicate)).ToList<RDFQuadruple>());
}
//In case of same S and O variable, must refine matching quadruples with a further value comparison
if (pattern.Subject.Equals(pattern.Object)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Subject.Equals(mt.Object)).ToList<RDFQuadruple>());
}
//In case of same P and O variable, must refine matching quadruples with a further value comparison
if (pattern.Predicate.Equals(pattern.Object)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Predicate.Equals(mt.Object)).ToList<RDFQuadruple>());
}
RDFQueryUtilities.AddColumn(resultTable, pattern.Context.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Subject.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Predicate.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Object.ToString());
RDFQueryEngine.PopulateTable(pattern, result, RDFQueryEnums.RDFPatternHoles.CSPO, resultTable);
}
}
}
}
}
//SPO pattern
else {
if (pattern.Subject is RDFResource) {
if (pattern.Predicate is RDFResource) {
//S->P->
result = store.SelectQuadruples(null,
(RDFResource)pattern.Subject,
(RDFResource)pattern.Predicate,
null,
null);
RDFQueryUtilities.AddColumn(resultTable, pattern.Object.ToString());
RDFQueryEngine.PopulateTable(pattern, result, RDFQueryEnums.RDFPatternHoles.O, resultTable);
}
else {
if (pattern.Object is RDFResource || pattern.Object is RDFLiteral) {
//S->->O
if (pattern.Object is RDFResource) {
result = store.SelectQuadruples(null,
(RDFResource)pattern.Subject,
null,
(RDFResource)pattern.Object,
null);
}
//S->->L
else {
result = store.SelectQuadruples(null,
(RDFResource)pattern.Subject,
null,
null,
(RDFLiteral)pattern.Object);
}
RDFQueryUtilities.AddColumn(resultTable, pattern.Predicate.ToString());
RDFQueryEngine.PopulateTable(pattern, result, RDFQueryEnums.RDFPatternHoles.P, resultTable);
}
else {
//S->->
result = store.SelectQuadruples(null,
(RDFResource)pattern.Subject,
null,
null,
null);
//In case of same P and O variable, must refine matching quadruples with a further value comparison
if (pattern.Predicate.Equals(pattern.Object)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Predicate.Equals(mt.Object)).ToList<RDFQuadruple>());
}
RDFQueryUtilities.AddColumn(resultTable, pattern.Predicate.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Object.ToString());
RDFQueryEngine.PopulateTable(pattern, result, RDFQueryEnums.RDFPatternHoles.PO, resultTable);
}
}
}
else {
if (pattern.Predicate is RDFResource) {
if (pattern.Object is RDFResource || pattern.Object is RDFLiteral) {
//->P->O
if (pattern.Object is RDFResource) {
result = store.SelectQuadruples(null,
null,
(RDFResource)pattern.Predicate,
(RDFResource)pattern.Object,
null);
}
//->P->L
else {
result = store.SelectQuadruples(null,
null,
(RDFResource)pattern.Predicate,
null,
(RDFLiteral)pattern.Object);
}
RDFQueryUtilities.AddColumn(resultTable, pattern.Subject.ToString());
RDFQueryEngine.PopulateTable(pattern, result, RDFQueryEnums.RDFPatternHoles.S, resultTable);
}
else {
//->P->
result = store.SelectQuadruples(null,
null,
(RDFResource)pattern.Predicate,
null,
null);
//In case of same S and O variable, must refine matching quadruples with a further value comparison
if (pattern.Subject.Equals(pattern.Object)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Subject.Equals(mt.Object)).ToList<RDFQuadruple>());
}
RDFQueryUtilities.AddColumn(resultTable, pattern.Subject.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Object.ToString());
RDFQueryEngine.PopulateTable(pattern, result, RDFQueryEnums.RDFPatternHoles.SO, resultTable);
}
}
else {
if (pattern.Object is RDFResource || pattern.Object is RDFLiteral) {
//->->O
if (pattern.Object is RDFResource) {
result = store.SelectQuadruples(null,
null,
null,
(RDFResource)pattern.Object,
null);
}
//->->L
else {
result = store.SelectQuadruples(null,
null,
null,
null,
(RDFLiteral)pattern.Object);
}
//In case of same S and P variable, must refine matching quadruples with a further value comparison
if (pattern.Subject.Equals(pattern.Predicate)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Subject.Equals(mt.Predicate)).ToList<RDFQuadruple>());
}
RDFQueryUtilities.AddColumn(resultTable, pattern.Subject.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Predicate.ToString());
RDFQueryEngine.PopulateTable(pattern, result, RDFQueryEnums.RDFPatternHoles.SP, resultTable);
}
else {
//->->
result = store.SelectQuadruples(null,
null,
null,
null,
null);
//In case of same S and P variable, must refine matching quadruples with a further value comparison
if (pattern.Subject.Equals(pattern.Predicate)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Subject.Equals(mt.Predicate)).ToList<RDFQuadruple>());
}
//In case of same S and O variable, must refine matching quadruples with a further value comparison
if (pattern.Subject.Equals(pattern.Object)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Subject.Equals(mt.Object)).ToList<RDFQuadruple>());
}
//In case of same P and O variable, must refine matching quadruples with a further value comparison
if (pattern.Predicate.Equals(pattern.Object)) {
result = new RDFMemoryStore(result.Quadruples.Values.Where(mt => mt.Predicate.Equals(mt.Object)).ToList<RDFQuadruple>());
}
RDFQueryUtilities.AddColumn(resultTable, pattern.Subject.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Predicate.ToString());
RDFQueryUtilities.AddColumn(resultTable, pattern.Object.ToString());
RDFQueryEngine.PopulateTable(pattern, result, RDFQueryEnums.RDFPatternHoles.SPO, resultTable);
}
}
}
}
return resultTable;
}
/// <summary>
/// Builds the table results of the pattern with values from the given graph
/// </summary>
internal static void PopulateTable(RDFPattern pattern, List<RDFTriple> triples, RDFQueryEnums.RDFPatternHoles variableFlavor, DataTable resultTable) {
var bindings = new Dictionary<String, String>();