SDB Store Description

Use of an SDB store requires a Store object which is described in two parts:

  • a connection to the database
  • a description of the store configuration

These can be built from a Jena assembler description.

Store objects themselves are lightweight so connections to an SDB database can be created on a per-request basis as required for use in J2EE application servers.

Contents

Store Descriptions

A store description identifies which storage layout is being used, the connection to use and the database type.

 [] rdf:type sdb:Store ;
     sdb:layout         "layout2" ;
     sdb:connection     <#conn> .

 <#conn> ...

SDB Connections

SDB connections, objects of class SDBConnection, abstract away from the details of the connection and also provide consist logging and transaction operations. Currently, SDB connections encapsulate JDBC connections but other connection technologies, such as direct database APIs, can be added.

Example

The sdbType is needed for both a connection and for a store description. It can be given in either part of the complete store description. If it is specified in both places, it must be the same.

@prefix rdfs:      <http://www.w3.org/2000/01/rdf-schema#> .
@prefix rdf:      <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix ja:       <http://jena.hpl.hp.com/2005/11/Assembler#> .
@prefix sdb:      <http://jena.hpl.hp.com/2007/sdb#> .

<#myStore> rdf:type sdb:Store ;
     sdb:layout         "layout2" ;
     sdb:connection     <#conn> ;
     .

<#conn> rdf:type sdb:SDBConnection ;
     sdb:sdbType        "derby" ;
     sdb:sdbName        "DB/SDB2" ;
     sdb:driver         "org.apache.derby.jdbc.EmbeddedDriver" ;
     .

Examples of assembler files are to be found in the Store/ directory in the distribution.

Vocabulary

Store

The value of sdbType needed for the connection also applies to choosing the store type.

layout ~ Layout type (e.g. "layout2", "layout2/hash" or "layout2/index").

connection ~ The object of this triple is the subject of the connection description.

engine ~ Set the MySQL engine type (MySQL only).

Connection

sdbType
The type of the database (e.g. "oracle", "MSSQLServerExpress", "postgresql", "mysql"). Controls both creating the JDBC URL, if not given explicitly, and the store type.
sdbName
Name used by the database service to select a database. Oracle SID.
sdbHost
Host name for the database server. Include :port to change the port from the default for the database.
sdbUser
sdbPassword
Database user name and password. The environment variables SDB_USER and SDB_PASSWORD are a better way to pass in the user and password because they are not then written into store description files. In Java programs, the system properties jena.db.user and jena.db.password can be used.
driver
The JDBC driver class name. Normally, the system looks up the sdbType to find the driver. Setting this property overrides that choice.
jdbcURL
If necessary, the JDBC URL can be set explicitly, not constructed by SDB. The sdbType is still needed.