A Enabling, Downgrading, or Removing Semantic Technologies Support

A.1.1 Enabling Semantic Technologies Support in a New Database Installation

To enable semantic technologies support in a new installation of Oracle Database Release 11.2 (or for an upgrade from Release 10.2 if no RDF network exists, as explained in Section A.1.3), follow these steps:

1. Connect to the database as the SYS user with SYSDBA privileges (SYS AS SYSDBA, and enter the SYS account password when prompted).

2. Start SQL*Plus, and enter the following statement:

   • Linux: @$ORACLE_HOME/md/admin/catsem.sql

   • Windows: @%ORACLE_HOME%\md\admin\catsem.sql

If a semantic network already exists, or if any semantic technologies types, tables, or PL/SQL packages already exist, the catsem.sql script exits with an error.

If the script completes successfully, a row with the following column values is inserted into the MDSYS.RDF_PARAMETER table:

• NAMESPACE: MDSYS

• ATTRIBUTE: SEM_VERSION

• VALUE: 112

• DESCRIPTION: VALID

If you use Workspace Manager with RDF data, you must also run the appropriate script after you run catsem.sql, as explained in Section 6.1, "Enabling Workspace Manager Support for RDF Data".

A.1.2 Upgrading Semantic Technologies Support from Release 11.1

If you are upgrading from Oracle Database Release 11.1 that includes the semantic technologies support for Release 11.1, the semantic technologies support is automatically upgraded to Release 11.2 when the database is upgraded. If you use Workspace Manager with RDF data, you must also run the appropriate script after the upgrade of semantic technologies support, as explained in Section 6.1.

However, you will also need to migrate RDF data if you have an existing Release 11.1 RDF network containing triples that include any of the following:

• Typed literal values of type xsd:float or xsd:double

• Literal values with a zero-length string as the value component

To check if you need to migrate RDF data, connect to the database as a user with DBA privileges and query the MDSYS.RDF_PARAMETER table, as follows:

SELECT namespace, attribute, value FROM mdsys.rdf_parameter
  WHERE namespace='MDSYS' 
  AND attribute IN ('FLOAT_DOUBLE_DECIMAL', 'NULL_LITERAL');

If the FLOAT_DOUBLE_DECIMAL and NULL_LITERAL attributes have the string value INVALID, you need to migrate RDF data. If the FLOAT_DOUBLE_DECIMAL and NULL_LITERAL attributes do not exist or have the string value VALID, you do not need to migrate RDF data, and you can skip the rest of this section.

To migrate RDF data, follow these steps:

1. Connect to the database as the SYS user with SYSDBA privileges (SYS AS SYSDBA, and enter the SYS account password when prompted).

2. Start SQL*Plus, and enter the following statement:

   EXECUTE sdo_rdf_internal.convert_old_rdf_data;
   

   The sdo_rdf_internal.convert_old_rdf_data procedure may take a significant amount of time to run if the semantic network contains many triples that are using (or affected by use of) xsd:float or xsd:double as the literal type or that are using a zero-length string as the object component.

3. Enter the following statement:

   • Linux: @$ORACLE_HOME/md/admin/semrelod.sql

   • Windows: @%ORACLE_HOME%\md\admin\semrelod.sql

A.1.3 Upgrading Semantic Technologies Support from Release 10.2

If you are upgrading from Oracle Database Release 10.2 that includes the semantic technologies support for Release 10.2, the actions required depend on whether there is an existing RDF network.

If there is not an existing RDF network, skip the rest of this section and follow the instructions in Section A.1.1, "Enabling Semantic Technologies Support in a New Database Installation".

If there is an existing RDF network, perform the following steps after the Oracle Database upgrade:

1. Connect to the database (Release 11.2) as the SYS user with SYSDBA privileges (SYS AS SYSDBA, and enter the SYS account password when prompted).

2. Start SQL*Plus, and enter the following statement:

   • Linux: @$ORACLE_HOME/md/admin/catsem10i.sql

   • Windows: @%ORACLE_HOME%\md\admin\catsem10i.sql

   The catsem10i.sql script enables Release 11.2 semantic technologies support and migrates RDF data from Release 10.2 to Release 11.2 format. The script may take a long time to run if the existing Release 10.2 RDF network contains a large amount of RDF data.

A.1.4 Spatial and Partitioning Requirements

Oracle Spatial must be installed before you can use any of the RDF and OWL capabilities. Oracle Locator is not sufficient. For information about Spatial and Locator, see Oracle Spatial Developer's Guide.

The Partitioning option must be enabled before you can use any of the RDF and OWL capabilities. For licensing information about the Partitioning option, see Oracle Database Licensing Information. For usage information about partitioning, see Oracle Database VLDB and Partitioning Guide.

A.2.1 Downgrading to Release 11.1 Semantic Technologies Support

If you need to downgrade to Oracle Database Release 11.1, the semantic technologies component will be downgraded automatically when you downgrade the database. However, any RDF or OWL data that is specific to Release 11.2 (that is, Release 11.2 RDF/OWL persistent structures that are not supported in previous versions) must be dropped before you perform the downgrade, so that the database is compatible with Release 11.1.

Any virtual models will not be preserved during a downgrade, because they are only available through a Release 11.1.0.7.0 patch (number 7600122) that was made available on My Oracle Support (MetaLink) in November, 2008. To use virtual models, you must reapply this patch after the downgrade, and then re-create the virtual models. For convenience, you can use the semvmrecreate.sql script to generate a script that you can later use (after the downgrade) to automatically re-create any virtual models that were present in the Release 11.2 semantic network. To do so, follow these steps before you downgrade the database :

1. Connect to the database (Release 11.2) as the SYS user with SYSDBA privileges (SYS AS SYSDBA, and enter the SYS account password when prompted).

2. Start SQL*Plus, and enter a statement in the following format:

   • Linux: @$ORACLE_HOME/md/admin/semvmrecreate.sql /my_dir_path/my_vm_recreate.sql

   • Windows: @%ORACLE_HOME%\md\admin\semvmrecreate.sql \my_dir_path\my_vm_recreate.sql

   where my_dir_path is the path to the location in which to create the my_vm_recreate.sql script file. (You can use another file name for the script, if you want.)

To check if any Release 11.2 RDF data is incompatible with Release 11.1, perform the following steps:

1. Connect to the database (Release 11.2) as the SYS user with SYSDBA privileges (SYS AS SYSDBA, and enter the SYS account password when prompted).

2. Start SQL*Plus, and enter the following statements:

   SET SERVEROUT ON
   EXECUTE SDO_SEM_DOWNGRADE.CHECK_111_COMPATIBLE;
   

If any RDF data is incompatible with Release 11.1, the procedure generates an error and displays a list of the incompatible data. In this case, you must run the semrelod111.sql script after the database downgrade, as follows:

1. In the Release 11.2 database, save a copy of the semrelod111.sql file, which is in the following location:

   • Linux: $ORACLE_HOME/md/admin/semrelod111.sql

   • Windows: %ORACLE_HOME%\md\admin\semrelod111.sql

2. If you have any virtual models that you want to be able to re-create after the download, run the semvmrecreate.sql script (if you have not already done so), as explained earlier in this section.

3. Remove any Release 11.2 release-specific RDF or OWL data (including virtual models) if you have not already done so, as explained earlier in this section.

4. Perform the database downgrade.

5. In the Release 11.1 database, copy the saved copy of the semrelod111.sql file to the following location:

   • Linux: $ORACLE_HOME/md/admin/

   • Windows: %ORACLE_HOME%\md\admin\

6. Connect to the Release 11.1 database as the SYS user with SYSDBA privileges (SYS AS SYSDBA, and enter the SYS account password when prompted).

7. Start SQL*Plus, and enter the following statement:

   • Linux: @$ORACLE_HOME/md/admin/semrelod111.sql

   • Windows: @%ORACLE_HOME%\md\admin\semrelod111.sql

   After the semrelod111.sql script completes successfully, Oracle semantic technologies support for Release 11.1 is enabled and ready to use, and all Release 11.1-compatible data is preserved.

8. If you want to enable support for virtual models, apply the Release 11.1.0.7 interim patch number 7600122.

9. If you previously generated a my_vm_recreate.sql script to re-create your virtual models after the downgrade, go to the my_dir_path location, connect to the database as the SYS user with SYSDBA privileges, start SQL*Plus, and run the my_vm_recreate.sql script.

A.2.2 Downgrading to Release 10.2 Semantic Technologies Support

If you need to downgrade to Oracle Database Release 10.2, follow the instructions in Section A.2.1 to downgrade to Release 11.1, and then follow the instructions in the rest of this section (taken from the Release 11.1 manual) to downgrade from Release 11.1 to Release 10.2.

If you need to downgrade to Oracle Database Release 10.2, and if you used Oracle Database Release 11 RDF or OWL features and want to preserve existing semantic data and rulebases, you must execute a statement to prepare for the downgrade, perform the downgrade, and execute another statement to restore the semantic data.

However, the following considerations apply:

• Entailed graph data will not be preserved, because the same information can be regenerated using the Oracle Database Release 10.2 RDF inference API.

• No rulebases or rules indexes related to OWL are preserved, because Oracle Database Release 10.2 did not support the OWL vocabulary.

Perform the following steps:

1. Before the database downgrade, connect to the Release 11 database as the SYS user with SYSDBA privileges (SYS AS SYSDBA, and enter the SYS account password when prompted).

2. Start SQL*Plus and enter the following statement:

   EXECUTE SDO_SEM_DOWNGRADE.PREPARE_DOWNGRADE_FROM_11;
   

   When this statement executes successfully, all existing semantic data and rulebases are saved. You will restore the semantic data after the database downgrade.

3. Perform the database downgrade.

4. Download the following file from the Semantic Technologies page of the Oracle Technology Network site: sdosemdgu.plb

5. If (and only if) your Oracle Database Release 10.2 release number is 10.2.0.1, click the Software link, and download and install the RDF-specific patch. (This patch is needed because Release 10.2.0.1 did not have the batch loading feature, which is used to restore the semantic data.)

6. Connect to the Release 10.2 database as the SYS user with SYSDBA privileges.

7. Start SQL*Plus and enter a statement in the following statement:

   EXECUTE SDO_SEM_DOWNGRADE_UTL.PREPARE_DOWNGRADE_TO_102('<tablespace-name>');
   

   Where <tablespace-name> is the name of the tablespace in which the RDF network will be created.

   When this statement executes successfully, all semantic data that had been saved before the downgrade is restored and ready to use.