This is the first of a series of blog posts about our experience with the IBM DB2 Express-C NoSQL Graph Store (hereafter DB2 RDF) in combination with IBM WebSphere Application Server Community Edition (hereafter WASCE).

The DB2 RDF product allows the storage and manipulation of RDF data. The data can be stored in graphs, all according to W3C Recommendations. The DB2 RDF product uses the Apache Jena programming model to interact with the underlying store. In the very detailed documentation there is an outline of products and tools needed to get the basic DB2 RDF programming environment going.

This series of articles is specifically about using the tools inside the WASCE environment. While developing our RESC.Info product we gathered a lot of experience which we like to share with the community using this article. We will also be presenting our experience during this years IBM Information On Demand 2013 in Las Vegas.

The series will cover the following topics:

• Configuring WASCE data sources
• Assembling the correct Jena distribution
• Dealing with transactions

This first article is about configuring WASCE data sources for use with the DB2 RDF and Jena programming model. This is NOT meant to be an extensive installation guide for these products, you should refer to the respective product documentation for more information on installation.
It is very important to select the correct versions of the various products:

• IBM DB2 Express-C 10.1.2
• IBM WebSphere Application Server Community Edition 3.0.4

Creating a DB2 database and graph store

To  be able to use the DB2 RDF features we need to create a standard database with some specific parameters. The DB2 documentation contains extensive information for this task. To create a database ‘STORE’ that supports DB2 RDF we issue the following commands:

db2 CREATE DATABASE STORE PAGESIZE 32 K

db2 UPDATE DATABASE CONFIGURATION FOR STORE USING LOGFILSIZ 20000

db2 CREATE TABLESPACE SYSTOOLSPACE IN IBMCATGROUP MANAGED BY AUTOMATIC STORAGE EXTENTSIZE 4

For the correct administration we also need to execute:

db2set DB2_ATS_ENABLE=YES

db2 UPDATE DB CONFIG USING AUTO_MAINT ON AUTO_TBL_MAINT ON AUTO_RUNSTATS ON

db2 alter bufferpool IBMDEFAULTBP IMMEDIATE SIZE 15000 AUTOMATIC

Now that the database is created we still need to create a graph store inside the database. This is done with the following command:

createrdfstore rdfStore  -db STORE -user db2admin -password XXX -schema public 

This can take a while. After completion you will have a graph store ‘rdfStore’ inside your database ‘STORE’. To check the presence of this store issue the following command when connected to ‘STORE’:

db2 SELECT * FROM SYSTOOLS.RDFSTORES

The resulting table should contain reference to our store ‘rdfStore’ in schema ‘public’

WebSphere Application Server Community Edition installation

Install WASCE with the installer, but do not start it yet. WASCE is distributed with some older DB2 JDBC drivers which interfere with the DB2 JDBC4 drivers that are needed for the DB2 RDF interface. In the repository directory of WASCE look for the path

<wasce_install>/repository/com/ibm

and delete the db2 sub-directory. Run WASCE with the -clean parameter, which causes WASCE to cleanup all references to the included DB2 JDBC drivers.

geronimo.[sh/bat] run -clean

Installing db2jcc4.jar

Now it is time to install the JDBC4 driver into WASCE repository. In the advanced mode of the console you will find the Resources/Repository tab where you can add new jars to the repository. Select the db2jcc4.jar from your <DB2_INST>/java directory and fill out the fields as shown in the image and click ‘Install’.

Creating a Database Pool

Once the correct jar is installed the creation of the connection to the database is the same as any other regular database connection. Select DB2 XA as ‘Database type’ and fill out the connection information. You should only see one JDBC driver here, the one we just installed. Fill out the details of your regular DB2 database ‘STORE’ and click ‘Deploy’.

After a database source object is created we can use it in the simple SQL entry field, select the newly created data source and issue the following command:

SELECT * FROM SYSTOOLS.RDFSTORES

The result should be the same as the result we had after issuing this query from the command line.

Conclusion

Now we have setup a DB2 RDF connection inside WASCE with the correct version of both products and connecting drivers. The next step will be to create a simple Jena based application to interact with the store.