RDF Semantic Graph Developer's Guide

584 Pages·2017·4.85 MB·English

Oracle® Spatial and Graph
RDF Semantic Graph Developer's Guide
12c Release 2 (12.2)
E85865-02
March 2019
Oracle Spatial and Graph RDF Semantic Graph Developer's Guide, 12c Release 2 (12.2)
E85865-02
Copyright © 2005, 2019, Oracle and/or its affiliates. All rights reserved.
Primary Author: Chuck Murray
Contributors: Eugene Inseok Chong, Souri Das, Matt Perry, Karl Rieb, Jags Srinivasan, Seema Sundara, Zhe
(Alan) Wu, Aravind Yalamanchi
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Contents
Preface
Audience xix
Documentation Accessibility xix
Related Documents xx
Conventions xx
Changes in This Release for Oracle Spatial and Graph RDF
Semantic Graph Developer's Guide
Changes in Oracle Database 12c Release 2 (12.2) xxi
Changes in Oracle Database 12c Release 1 (12.1.0.2) xxiii
Changes in Oracle Database 12c Release 1 (12.1.0.1) xxiv
Changes for RDF Semantic Graph Support for Apache Jena xxvi
Part I
Conceptual and Usage Information
1 RDF Semantic Graph Overview
1.1 Introduction to Oracle Semantic Technologies Support 1-3
1.2 Semantic Data Modeling 1-4
1.3 Semantic Data in the Database 1-4
1.3.1 Metadata for Models 1-5
1.3.2 Statements 1-6
1.3.2.1 Triple Uniqueness and Data Types for Literals 1-8
1.3.3 Subjects and Objects 1-9
1.3.4 Blank Nodes 1-9
1.3.5 Properties 1-9
1.3.6 Inferencing: Rules and Rulebases 1-9
1.3.7 Entailments (Rules Indexes) 1-12
1.3.8 Virtual Models 1-14
1.3.9 Named Graphs 1-17
1.3.9.1 Data Formats Related to Named Graph Support 1-17
iii
1.3.10 Semantic Data Security Considerations 1-18
1.4 Semantic Metadata Tables and Views 1-19
1.5 Semantic Data Types, Constructors, and Methods 1-20
1.5.1 Constructors for Inserting Triples 1-22
1.6 Using the SEM_MATCH Table Function to Query Semantic Data 1-23
1.6.1 Performing Queries with Incomplete or Invalid Entailments 1-30
1.6.2 Graph Patterns: Support for Curly Brace Syntax, and OPTIONAL,
FILTER, UNION, and GRAPH Keywords 1-30
1.6.2.1 GRAPH Keyword Support 1-38
1.6.3 Graph Patterns: Support for SPARQL ASK Syntax 1-39
1.6.4 Graph Patterns: Support for SPARQL CONSTRUCT Syntax 1-40
1.6.4.1 Typical SPARQL CONSTRUCT Workflow 1-44
1.6.5 Graph Patterns: Support for SPARQL DESCRIBE Syntax 1-45
1.6.6 Graph Patterns: Support for SPARQL SELECT Syntax 1-46
1.6.7 Graph Patterns: Support for SPARQL 1.1 Constructs 1-51
1.6.7.1 Expressions in the SELECT Clause 1-51
1.6.7.2 Subqueries 1-52
1.6.7.3 Grouping and Aggregation 1-52
1.6.7.4 Negation 1-55
1.6.7.5 Value Assignment 1-57
1.6.7.6 Property Paths 1-60
1.6.8 Graph Patterns: Support for SPARQL 1.1 Federated Query 1-62
1.6.8.1 Privileges Required to Execute Federated SPARQL Queries 1-63
1.6.8.2 SPARQL SERVICE Join Push Down 1-63
1.6.8.3 SPARQL SERVICE SILENT 1-64
1.6.8.4 Using a Proxy Server with SPARQL SERVICE 1-64
1.6.8.5 Accessing SPARQL Endpoints with HTTP Basic Authentication 1-65
1.6.9 Inline Query Optimizer Hints 1-65
1.6.10 Full-Text Search 1-67
1.6.11 Spatial Support 1-70
1.6.11.1 OGC GeoSPARQL Support 1-70
1.6.11.2 Representing Spatial Data in RDF 1-70
1.6.11.3 Validating Geometries 1-72
1.6.11.4 Indexing Spatial Data 1-72
1.6.11.5 Querying Spatial Data 1-73
1.6.11.6 Using Long Literals with GeoSPARQL Queries 1-73
1.6.12 Flashback Query Support 1-74
1.6.13 Best Practices for Query Performance 1-75
1.6.13.1 FILTER Constructs Involving xsd:dateTime, xsd:date, and
xsd:time 1-76
1.6.13.2 Function-Based Indexes for FILTER Constructs Involving Typed
Literals 1-76
iv
1.6.13.3 FILTER Constructs Involving Relational Expressions 1-76
1.6.13.4 Optimizer Statistics and Dynamic Sampling 1-77
1.6.13.5 Multi-Partition Queries 1-77
1.6.13.6 Compression on Systems with OLTP Index Compression 1-78
1.6.13.7 Unbounded Property Path Expressions 1-78
1.6.13.8 Nested Loop Pushdown for Property Paths 1-78
1.6.13.9 Grouping and Aggregation 1-79
1.6.13.10 Use of Bind Variables to Reduce Compilation Time 1-79
1.6.13.11 Non-Null Expression Hints 1-81
1.6.14 Special Considerations When Using SEM_MATCH 1-82
1.7 Using the SEM_APIS.SPARQL_TO_SQL Function to Query Semantic Data 1-83
1.7.1 Using Bind Variables with SEM_APIS.SPARQL_TO_SQL 1-84
1.7.2 SEM_MATCH and SEM_APIS.SPARQL_TO_SQL Compared 1-88
1.8 Loading and Exporting Semantic Data 1-88
1.8.1 Bulk Loading Semantic Data Using a Staging Table 1-89
1.8.1.1 Loading the Staging Table 1-90
1.8.1.2 Recording Event Traces During Bulk Loading 1-91
1.8.2 Batch Loading N-Triple Format Semantic Data Using the Java API 1-92
1.8.3 Loading Semantic Data Using INSERT Statements 1-93
1.8.3.1 Loading Data into Named Graphs Using INSERT Statements 1-94
1.8.4 Exporting Semantic Data 1-94
1.8.4.1 Retrieving Semantic Data from an Application Table 1-94
1.8.4.2 Retrieving Semantic Data from an RDF Model 1-95
1.8.4.3 Removing Model and Graph Information from Retrieved Blank
Node Identifiers 1-96
1.8.5 Exporting or Importing a Semantic Network Using Oracle Data Pump 1-97
1.8.6 Purging Unused Values 1-98
1.9 Using Semantic Network Indexes 1-100
1.9.1 MDSYS.SEM_NETWORK_INDEX_INFO View 1-102
1.10 Using Data Type Indexes 1-102
1.11 Managing Statistics for Semantic Models and the Semantic Network 1-104
1.11.1 Saving Statistics at a Model Level 1-105
1.11.2 Restoring Statistics at a Model Level 1-105
1.11.3 Saving Statistics at the Network Level 1-106
1.11.4 Restoring Statistics at the Network Level 1-106
1.11.5 Setting Statistics at a Model Level 1-107
1.11.6 Deleting Statistics at a Model Level 1-107
1.12 Support for SPARQL Update Operations on a Semantic Model 1-107
1.12.1 Tuning the Performance of SPARQL Update Operations 1-117
1.12.2 Transaction Management with SPARQL Update Operations 1-118
1.12.2.1 Transaction Isolation Levels 1-121
v
1.12.3 Support for Bulk Operations 1-122
1.12.3.1 Materialization of Intermediate Data (STREAMING=F) 1-122
1.12.3.2 Using SEM_APIS.BULK_LOAD_FROM_STAGING_TABLE 1-123
1.12.3.3 Using Delete as Insert (DEL_AS_INS=T) 1-123
1.12.4 Setting UPDATE_MODEL Options at the Session Level 1-124
1.12.5 Load Operations: Special Considerations for SPARQL Update 1-124
1.12.6 Long Literals: Special Considerations for SPARQL Update 1-125
1.12.7 Blank Nodes: Special Considerations for SPARQL Update 1-125
1.13 Enhanced RDF ORDER BY Query Processing 1-126
1.14 Quick Start for Using Semantic Data 1-126
1.15 Semantic Data Examples (PL/SQL and Java) 1-127
1.15.1 Example: Journal Article Information 1-127
1.15.2 Example: Family Information 1-130
1.16 Software Naming Changes Since Release 11.1 1-136
1.17 For More Information About RDF Semantic Graph 1-137
1.18 Required Migration of Pre-12.2 Semantic Data 1-138
2 OWL Concepts
2.1 Ontologies 2-1
2.1.1 Example: Disease Ontology 2-1
2.1.2 Supported OWL Subsets 2-3
2.2 Using OWL Inferencing 2-5
2.2.1 Creating a Simple OWL Ontology 2-6
2.2.2 Performing Native OWL inferencing 2-6
2.2.3 Performing OWL and User-Defined Rules Inferencing 2-7
2.2.4 Generating OWL inferencing Proofs 2-8
2.2.5 Validating OWL Models and Entailments 2-10
2.2.6 Using SEM_APIS.CREATE_ENTAILMENT for RDFS Inference 2-11
2.2.7 Enhancing Inference Performance 2-11
2.2.8 Optimizing owl:sameAs Inference 2-12
2.2.8.1 Querying owl:sameAs Consolidated Inference Graphs 2-13
2.2.9 Performing Incremental Inference 2-14
2.2.10 Using Parallel Inference 2-15
2.2.11 Using Named Graph Based Inferencing (Global and Local) 2-16
2.2.11.1 Named Graph Based Global Inference (NGGI) 2-16
2.2.11.2 Named Graph Based Local Inference (NGLI) 2-17
2.2.11.3 Using NGGI and NGLI Together 2-18
2.2.12 Performing Selective Inferencing (Advanced Information) 2-19
2.3 Using Semantic Operators to Query Relational Data 2-20
2.3.1 Using the SEM_RELATED Operator 2-20
vi
2.3.2 Using the SEM_DISTANCE Ancillary Operator 2-22
2.3.2.1 Computation of Distance Information 2-23
2.3.3 Creating a Semantic Index of Type MDSYS.SEM_INDEXTYPE 2-23
2.3.4 Using SEM_RELATED and SEM_DISTANCE When the Indexed
Column Is Not the First Parameter 2-24
2.3.5 Using URIPREFIX When Values Are Not Stored as URIs 2-25
3 Simple Knowledge Organization System (SKOS) Support
3.1 Supported and Unsupported SKOS Semantics 3-2
3.1.1 Supported SKOS Semantics 3-2
3.1.2 Unsupported SKOS Semantics 3-3
3.2 Performing Inference on SKOS Models 3-3
3.2.1 Validating SKOS Models and Entailments 3-4
3.2.2 Property Chain Handling 3-4
4 Semantic Indexing for Documents
4.1 Information Extractors for Semantically Indexing Documents 4-3
4.2 Extractor Policies 4-5
4.3 Semantically Indexing Documents 4-5
4.4 SEM_CONTAINS and Ancillary Operators 4-6
4.4.1 SEM_CONTAINS_SELECT Ancillary Operator 4-7
4.4.2 SEM_CONTAINS_COUNT Ancillary Operator 4-8
4.5 Searching for Documents Using SPARQL Query Patterns 4-8
4.6 Bindings for SPARQL Variables in Matching Subgraphs in a Document
(SEM_CONTAINS_SELECT Ancillary Operator) 4-9
4.7 Improving the Quality of Document Search Operations 4-10
4.8 Indexing External Documents 4-11
4.9 Configuring the Calais Extractor type 4-13
4.10 Working with General Architecture for Text Engineering (GATE) 4-13
4.11 Creating a New Extractor Type 4-14
4.12 Creating a Local Semantic Index on a Range-Partitioned Table 4-16
4.13 Altering a Semantic Index 4-16
4.13.1 Rebuilding Content for All Existing Policies in a Semantic Index 4-17
4.13.2 Rebuilding to Add Content for a New Policy to a Semantic Index 4-17
4.13.3 Rebuilding Content for an Existing Policy from a Semantic Index 4-17
4.13.4 Rebuilding to Drop Content for an Existing Policy from a Semantic
Index 4-17
4.14 Passing Extractor-Specific Parameters in CREATE INDEX and ALTER
INDEX 4-17
4.15 Performing Document-Centric Inference 4-18
vii
4.16 Metadata Views for Semantic Indexing 4-19
4.16.1 MDSYS.RDFCTX_POLICIES View 4-19
4.16.2 RDFCTX_INDEX_POLICIES View 4-19
4.16.3 RDFCTX_INDEX_EXCEPTIONS View 4-20
4.17 Default Style Sheet for GATE Extractor Output 4-21
5 Fine-Grained Access Control for RDF Data
5.1 Triple-Level Security 5-1
5.1.1 Fine-Grained Security for Inferred Data and Ladder-Based Inference
(LBI) 5-3
5.1.2 Extended Example: Applying OLS Triple-Level Security on Semantic
Data 5-5
5.2 Resource-Level Security 5-11
5.2.1 Securing RDF Subjects 5-12
5.2.2 Securing RDF Predicates 5-13
5.2.3 Securing RDF Objects 5-13
5.2.4 Generating Labels for Inferred Triples 5-14
5.2.5 Using Labels Based on Application Logic 5-16
5.2.6 RDFOLS_SECURE_RESOURCE View 5-18
6 RDF Semantic Graph Support for Apache Jena
6.1 Setting Up the Software Environment 6-3
6.1.1 If You Used a Previous Version of the Support for Apache Jena 6-4
6.2 Setting Up the SPARQL Service 6-5
6.2.1 Creating the Required Data Source Using WebLogic Server 6-7
6.2.2 Configuring the Joseki-Based SPARQL Service 6-8
6.2.2.1 Client Identifiers 6-10
6.2.2.2 Using OLTP Compression for Application Tables and Staging
Tables 6-10
6.2.3 Configuring the Fuseki-Based SPARQL Service 6-11
6.2.4 Terminating Long-Running SPARQL Queries 6-11
6.2.5 N-Triples Encoding for Non-ASCII Characters 6-11
6.3 Setting Up a Dynamic SPARQL Endpoint 6-12
6.3.1 Configuring the Dynamic SPARQL Endpoint in the Fuseki Server 6-12
6.3.2 Configuring the Dynamic SPARQL Endpoint in the Joseki Servlet 6-13
6.4 Adding Cross-Site Request Forgery (CSRF) Protection to the Joseki Servlet 6-16
6.4.1 Configuring the Joseki Server to Add Cross-Site Request Forgery
Protection 6-16
6.4.2 Configuring the Joseki Client to Add Cross-Site Request Forgery
Protection 6-17
6.5 Setting Up the RDF Semantic Graph Environment 6-18
viii
6.6 SEM_MATCH and RDF Semantic Graph Support for Apache Jena Queries
Compared 6-19
6.7 Retrieving User-Friendly Java Objects from SEM_MATCH or SQL-Based
Query Results 6-20
6.8 Optimized Handling of SPARQL Queries 6-23
6.8.1 Compilation of SPARQL Queries to a Single SEM_MATCH Call 6-24
6.8.2 Optimized Handling of Property Paths 6-24
6.9 Additions to the SPARQL Syntax to Support Other Features 6-25
6.9.1 SQL Hints 6-26
6.9.2 Using Bind Variables in SPARQL Queries 6-26
6.9.3 Additional WHERE Clause Predicates 6-28
6.9.4 Additional Query Options 6-29
6.9.4.1 JOIN Option and Federated Queries 6-30
6.9.4.2 S2S Option Benefits and Usage Information 6-31
6.9.5 Midtier Resource Caching 6-32
6.10 Functions Supported in SPARQL Queries through RDF Semantic Graph
Support for Apache Jena 6-32
6.10.1 Functions in the ARQ Function Library 6-33
6.10.2 Native Oracle Database Functions for Projected Variables 6-33
6.10.3 User-Defined Functions 6-34
6.11 SPARQL Update Support 6-37
6.12 Analytical Functions for RDF Data 6-40
6.12.1 Generating Contextual Information about a Path in a Graph 6-46
6.13 Support for Server-Side APIs 6-47
6.13.1 Virtual Models Support 6-47
6.13.2 Connection Pooling Support 6-48
6.13.3 Semantic Model PL/SQL Interfaces 6-50
6.13.4 Inference Options 6-50
6.13.5 PelletInfGraph Class Support Deprecated 6-53
6.14 Bulk Loading Using RDF Semantic Graph Support for Apache Jena 6-53
6.14.1 Using prepareBulk in Parallel (Multithreaded) Mode 6-56
6.14.2 Handling Illegal Syntax During Data Loading 6-58
6.15 Automatic Variable Renaming 6-59
6.16 JavaScript Object Notation (JSON) Format Support 6-60
6.17 Other Recommendations and Guidelines 6-62
6.17.1 BOUND or !BOUND Instead of EXISTS or NOT EXISTS 6-62
6.17.2 SPARQL 1.1 SELECT Expressions 6-62
6.17.3 Syntax Involving Bnodes (Blank Nodes) 6-63
6.17.4 Limit in the SERVICE Clause 6-63
6.17.5 OracleGraphWrapperForOntModel Class for Better Performance 6-63
6.18 Example Queries Using RDF Semantic Graph Support for Apache Jena 6-65
6.18.1 Test.java: Query Family Relationships 6-66
ix
6.18.2 Test6.java: Load OWL Ontology and Perform OWLPrime inference 6-67
6.18.3 Test7.java: Bulk Load OWL Ontology and Perform OWLPrime
inference 6-69
6.18.4 Test8.java: SPARQL OPTIONAL Query 6-70
6.18.5 Test9.java: SPARQL Query with LIMIT and OFFSET 6-71
6.18.6 Test10.java: SPARQL Query with TIMEOUT and DOP 6-73
6.18.7 Test11.java: Query Involving Named Graphs 6-74
6.18.8 Test12.java: SPARQL ASK Query 6-76
6.18.9 Test13.java: SPARQL DESCRIBE Query 6-76
6.18.10 Test14.java: SPARQL CONSTRUCT Query 6-77
6.18.11 Test15.java: Query Multiple Models and Specify "Allow Duplicates" 6-79
6.18.12 Test16.java: SPARQL Update 6-80
6.18.13 Test17.java: SPARQL Query with ARQ Built-In Functions 6-81
6.18.14 Test18.java: SELECT Cast Query 6-82
6.18.15 Test19.java: Instantiate Oracle Database Using OracleConnection 6-83
6.18.16 Test20.java: Oracle Database Connection Pooling 6-84
6.19 SPARQL Gateway and Semantic Data 6-86
6.19.1 SPARQL Gateway Features and Benefits Overview 6-86
6.19.2 Installing and Configuring SPARQL Gateway 6-87
6.19.2.1 Download the RDF Semantic Graph Support for Apache
Jena .zip File (if Not Already Done) 6-87
6.19.2.2 Deploy SPARQL Gateway in WebLogic Server 6-87
6.19.2.3 Modify Proxy Settings, if Necessary 6-88
6.19.2.4 Configure the OracleSGDS Data Source, if Necessary 6-88
6.19.2.5 Add and Configure the SparqlGatewayAdminGroup Group, if
Desired 6-88
6.19.3 Using SPARQL Gateway with Semantic Data 6-89
6.19.3.1 Storing SPARQL Queries and XSL Transformations 6-89
6.19.3.2 Specifying a Timeout Value 6-91
6.19.3.3 Specifying Best Effort Query Execution 6-91
6.19.3.4 Specifying a Content Type Other Than text/xml 6-92
6.19.4 Customizing the Default XSLT File 6-92
6.19.5 Using the SPARQL Gateway Java API 6-93
6.19.6 Using the SPARQL Gateway Graphical Web Interface 6-96
6.19.6.1 Main Page (index.html) 6-96
6.19.6.2 Navigation and Browsing Page (browse.jsp) 6-97
6.19.6.3 XSLT Management Page (xslt.jsp) 6-99
6.19.6.4 SPARQL Management Page (sparql.jsp) 6-100
6.19.7 Using SPARQL Gateway as an XML Data Source to OBIEE 6-101
6.20 Deploying Joseki in Apache Tomcat or JBoss 6-104
6.20.1 Deploying Joseki in Apache Tomcat 6.0.29 or 7.0.42 6-104
x