RDF Overview. This chapter describes the support for the Resource Description Framework RDF in the Oracle Spatial network data model. It assumes that you are familiar with the major concepts associated with RDF, such as reification, containers, and collections. This chapter does not explain these concepts in detail, but focuses instead on how the concepts are implemented in the network data model. For an excellent explanation of RDF concepts, see the World Wide Web Consortium W3. C RDF Primer at http www. TRrdf primer. It is also helpful is you are familiar with the concepts and techniques of the network data model, as described in Oracle Spatial Topology and Network Data Models. The PLSQL subprograms for working with RDF are in the SDORDF package, which is documented in Chapter 2, and in the SDORDFINFERENCE package, which is documented in Chapter 3. RDF and the Network Data Model. RDF is a language used to describe metadata, particularly for information found on the Web. In addition to its formal semantics, RDF has a simple data structure that is effectively modeled using a directed graph. To describe metadata in the network data model implementation of RDF, the metadata statements are represented as triples nodes are used to represent two parts of the triple, and the third part is represented by a directed link that describes the relationship between the nodes. The triples are stored in a logical network. Oracle Rdf Reports' title='Oracle Rdf Reports' />Working with BLOB data. Open file on disk FileStream fs new. Connect for Oracle writes LOB data to Oracle and then returns initialized. Download Amazon.Com The Brink Of Bankruptcy Pdf. Having trouble opening RDF files Learn the most common reasons why you cant open RDF files and how to open them quickly and easily. In addition, Spatial maintains information about different RDF models. RDF statements are expressed in triples subject or resource, predicate or property, object or value. In this chapter subject, property, object is used to describe a triple, and the terms statement and triple may sometimes be used interchangeably. D195A64.png' alt='Oracle Rdf File' title='Oracle Rdf File' />Each triple is a complete and unique fact about a specific domain, and can be represented by a link in a directed graph. In additional to logical network information, spatial information such as node locations and link geometries can be associated with the network. Entity framework clob,entity framework clob. File Extension RDF. Oracle Database and OpenOffice Spreadsheet will also open RDF files in. RDF Data Model in the Database. There is one universe for all RDF data stored in the database. All RDF triples are parsed and stored in the system as entries in tables under the MDSYS schema. An RDF triple subject, property, object is treated as one database object. As a result, a single RDF document containing multiple triples results in multiple database objects. All the subjects and objects of triples are mapped to nodes in a network, and properties are mapped to network links that have their start node and end node as subject and object, respectively. The possible node types in an RDF network are blank nodes, URIs, plain literals, and typed literals. Oracle Database has a type named URIType to hold instances of any URI Http. Uri, DBUri, and XDBUri. This type is used to store the names of the nodes and links in the RDF network. The following RDF requirements apply to the specifications of URIs and the storage of RDF data in the database A subject must be a URI or a blank node. A property must be a URI. An object can be any type, such as a URI, a blank node, or a literal. However, null values and null strings are not supported. Metadata for RDF Models. The MDSYS. RDFMODEL system table contains information about all RDF models defined in the database. When you create a model using the SDORDF. CREATERDFMODEL procedure, you specify a name for the model, as well as a table and column to hold references to the RDF data, and the system automatically generates a model ID. Oracle maintains the MDSYS. RDFMODEL table automatically when you create and drop RDF models. Users should never modify this table directly. For example, do not use SQL INSERT, UPDATE, or DELETE statements with this table. The MDSYS. RDFMODEL table contains the columns shown in Table 1 1. Table 1 1 MDSYS. RDFMODEL Table Columns. Column Name. Data Type. Description. OWNERVARCHAR23. Schema of the owner of the RDF model. MODELIDNUMBERUnique model ID number, automatically generated by Spatial. MODELNAMEVARCHAR22. Name of the model. TABLENAMEVARCHAR23. Name of the table to hold references to RDF data for the model. COLUMNNAMEVARCHAR23. Name of the column of type SDORDFTRIPLES in the table to hold references to RDF data for the model. When you create an RDF model, a view for the RDF triples associated with the model is also created under the MDSYS schema. This view has a name in the format RDFMmodel name, and it is visible only to the owner of the model and to users with suitable privileges. Each MDSYS. RDFMmodel name view contains a row for each triple stored as a link in a network, and it has the columns shown in Table 1 2. Table 1 2 MDSYS. RDFMmodel name View Columns. Column Name. Data Type. Description. LINKIDNUMBERThe unique triple identifier and part of the primary key. STARTNODEIDNUMBERThe VALUEID for the text value of the subject of the triple. Also part of the primary key. ENDNODEIDNUMBERThe VALUEID for the text value of the object of the triple. CANONENDNODEIDNUMBERThe VALUEID for the text value of the canonical form of the object of the triple. Also part of the primary key. LINKTYPEVARCHAR22. The type of predicate represented by the URI of the PVALUEID. STANDARD, RDFMEMBER, and RDFTYPE are some of the supported types. ACTIVEVARCHAR21The status of the link in the network contains Y if the link is active contains N if the link is not active. LINKLEVELNUMBERPriority level for the link used for hierarchical modeling, so that links with higher priority levels can be considered first in computing a path. COSTNUMBERThe number of times the triple is stored in an application table. The triple is only stored once in an RDF system table, but may exist in several rows in a users application table. PARENTLINKIDNUMBERLink ID of the parent link of this link. BIDIRECTEDVARCHAR21Contains Y if the link is bidirected that is, can be traversed either from the start node to the end node or from the end node to the start node, or N if the link is unidirected in one direction only, from the start node to the end node. PVALUEIDNUMBERThe VALUEID for the text value of the predicate of the triple. CONTEXTVARCHAR21Reserved for future use currently D. REIFLINKVARCHAR21Reserved for future use currently N. MODELIDNUMBERThe ID for the RDF graph to which the triple belongs. It logically partitions the table by RDF graphs. Namespaces. The MDSYS. RDFNAMESPACE system table contains information about namespaces. Namespaces are used in RDF XML documents to make the documents more readable. In the Oracle RDF data model, namespaces are stored directly with their subjects, properties, and objects. However, Oracle does not use the MDSYS. RDFNAMESPACE table in any of its internal operations the table is provided as a convenience to users who may want to store namespaces that are used in their models. Oracle adds to the MDSYS. RDFNAMESPACE table automatically when you add namespaces using the SDORDF. ADDNAMESPACES procedure. Do not use SQL INSERT statements to add namespaces this table. The MDSYS. RDFNAMESPACE table contains the columns shown in Table 1 3. Table 1 3 MDSYS. RDFNAMESPACE Table Columns. Column Name. Data Type. Description. NAMESPACEIDNUMBERUnique namespace ID number, automatically generated by Spatial. NAMESPACENAMESYS. URITYPEName of the namespace. Currently, namespaces are used by the Spatial network data model only for cataloging. Statements. The MDSYS.