26 Using PL/SQL to Access the Repository

This chapter describes the Oracle XML DB resource application program interface (API) for PL/SQL (PL/SQL package DBMS_XDB). It contains these topics:

Overview of PL/SQL Package DBMS_XDB
DBMS_XDB: Resource Management
DBMS_XDB: ACL-Based Security Management
DBMS_XDB: Configuration Management

Overview of PL/SQL Package DBMS_XDB

PL/SQL package DBMS_XDB is the Oracle XML DB resource application program interface (API) for PL/SQL. It is also known as the PL/SQL foldering API. This API provides functions and procedures to access and manage Oracle XML DB Repository resources using PL/SQL. It includes methods for managing resource security and Oracle XML DB configuration.

Oracle XML DB Repository is modeled on XML, and provides a database file system for any data. The repository maps path names (or URLs) onto database objects of XMLType and provides management facilities for these objects.

PL/SQL package DBMS_XDB is an API that you can use to manage all of the following:

Oracle XML DB resources
Oracle XML DB security based on access control lists (ACLs). An ACL is a list of access control entries (ACEs) that determines which principals (users and roles) have access to which resources
Oracle XML DB configuration

See Also:

DBMS_XDB: Resource Management

Table 26-1 describes the DBMS_XDB Oracle XML DB resource management functions and procedures.

Table 26-1 DBMS_XDB Resource Management Functions and Procedures

Function/Procedure	Description
`appendResourceMetadata`	Add user-defined metadata to a resource.
`createFolder`	Create a new folder resource.
`createOIDPath`	Create a virtual path to a resource, based on its object identifier (OID).
`createResource`	Create a new file resource.
`deleteResource`	Delete a resource from the repository.
`deleteResourceMetadata`	Delete specific user-defined metadata from a resource.
`existsResource`	Indicate whether or not a resource exists, given its absolute path.
`getLockToken`	Return a resource lock token for the current user, given a path to the resource.
`getResOID`	Return the object identifier (OID) of a resource, given its absolute path.
`getXDB_tablespace`	Return the current tablespace of database schema (user account) `XDB`.
`link`	Create a link to an existing resource.
lockResource	Obtain a WebDAV-style lock on a resource, given a path to the resource.
`moveXDB_tablespace`	Move user `XDB` to the specified tablespace.
`purgeResourceMetadata`	Delete all user-defined metadata from a resource.
`rebuildHierarchicalIndex`	Rebuild the hierarchical repository index, after import or export operations.
`renameResource`	Rename a resource.
`unlockResource`	Unlock a resource, given its lock token and path.
`updateResourceMetadata`	Modify user-defined resource metadata.

The examples in this section illustrate the use of these functions and procedures.

Example 26-1 Using DBMS_XDB to Manage Resources

This example uses package DBMS_XDB to manage repository resources. It creates the following:

a folder, mydocs, under folder /public
two file resources, emp_selby.xml and emp_david.xml
two links to the file resources, person_selby.xml and person_david.xml

It then deletes each of the newly created resources and links. The folder contents are deleted before the folder itself.

DECLARE
  retb BOOLEAN;
BEGIN
  retb := DBMS_XDB.createfolder('/public/mydocs');
  retb := DBMS_XDB.createresource('/public/mydocs/emp_selby.xml',
                                  '<emp_name>selby</emp_name>');
  retb := DBMS_XDB.createresource('/public/mydocs/emp_david.xml',
                                  '<emp_name>david</emp_name>');
END;
/
PL/SQL procedure successfully completed.
 
CALL DBMS_XDB.link('/public/mydocs/emp_selby.xml',
                   '/public/mydocs',
                   'person_selby.xml');
Call completed.
 
CALL DBMS_XDB.link('/public/mydocs/emp_david.xml',
                   '/public/mydocs',
                   'person_david.xml');
Call completed.
 
CALL DBMS_XDB.deleteresource('/public/mydocs/emp_selby.xml');
Call completed.
 
CALL DBMS_XDB.deleteresource('/public/mydocs/person_selby.xml');
Call completed.
 
CALL DBMS_XDB.deleteresource('/public/mydocs/emp_david.xml');
Call completed.
 
CALL DBMS_XDB.deleteresource('/public/mydocs/person_david.xml');
Call completed.
 
CALL DBMS_XDB.deleteresource('/public/mydocs');
Call completed.

See Also:

Chapter 29, "User-Defined Repository Metadata" for examples using appendResourceMetadata and deleteResourceMetadata

DBMS_XDB: ACL-Based Security Management

Table 26-2 lists the DBMS_XDB Oracle XML DB ACL- based security management functions and procedures.

Table 26-2 DBMS_XDB: Security Management Procedures and Functions

Function/Procedure	Description
`ACLCheckPrivileges`	Checks the access privileges granted to the current user by an ACL.
`changePrivileges`	Adds an ACE to a resource ACL.
`checkPrivileges`	Checks the access privileges granted to the current user for a resource.
`getACLDocument`	Retrieves the ACL document that protects a resource, given the path name of the resource.
`getPrivileges`	Returns all privileges granted to the current user for a resource.
`setACL`	Sets the ACL on a resource.

See Also:

The examples in this section illustrate the use of these functions and procedures.

Example 26-2 Using Procedure DBMS_XDB.getACLDocument

In this example, database sample-schema user hr creates two resources: a folder, /public/mydocs, with a file in it, emp_selby.xml. Procedure getACLDocument is called on the file resource, showing that the <principal> user for the document is PUBLIC.

CONNECT hr/hr
Connected.

DECLARE
  retb BOOLEAN;
BEGIN
  retb := DBMS_XDB.createFolder('/public/mydocs');
  retb := DBMS_XDB.createResource('/public/mydocs/emp_selby.xml',
                                  '<emp_name>selby</emp_name>');
END;
/
PL/SQL procedure successfully completed.
 
SELECT DBMS_XDB.getACLDocument('/public/mydocs/emp_selby.xml').getCLOBVal()
  FROM DUAL;
 
DBMS_XDB.GETACLDOCUMENT('/PUBLIC/MYDOCS/EMP_SELBY.XML').GETCLOBVAL()
--------------------------------------------------------------------------------
<acl description="Public:All privileges to PUBLIC" xmlns="http://xmlns.oracle.co
m/xdb/acl.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaL
ocation="http://xmlns.oracle.com/xdb/acl.xsd                           http://xm
lns.oracle.com/xdb/acl.xsd">
  <ace>
    <principal>PUBLIC</principal>
    <grant>true</grant>
    <privilege>
      <all/>
    </privilege>
  </ace>
</acl>
 
1 row selected.

Example 26-3 Using Procedure DBMS_XDB.setACL

In this example, the system manager connects and uses procedure setACL to give the owner (hr) all privileges on the file resource created in Example 26-2. Procedure getACLDocument then shows that the <principal> user is dav:owner, the owner (hr).

CONNECT SYSTEM/MANAGER
Connected.
 
-- Give all privileges to owner, HR.
CALL DBMS_XDB.setACL('/public/mydocs/emp_selby.xml',
                     '/sys/acls/all_owner_acl.xml');
Call completed.
COMMIT;
Commit complete.
 
SELECT DBMS_XDB.getACLDocument('/public/mydocs/emp_selby.xml').getCLOBVal()
  FROM DUAL;

DBMS_XDB.GETACLDOCUMENT('/PUBLIC/MYDOCS/EMP_SELBY.XML').GETCLOBVAL()
--------------------------------------------------------------------------------
<acl description="Private:All privileges to OWNER only and not accessible to oth
ers" xmlns="http://xmlns.oracle.com/xdb/acl.xsd" xmlns:dav="DAV:" xmlns:xsi="htt
p://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.oracle.
com/xdb/acl.xsd                           http://xmlns.oracle.com/xdb/acl.xsd">
  <ace>
    <principal>dav:owner</principal>
    <grant>true</grant>
    <privilege>
      <all/>
    </privilege>
  </ace>
</acl>
 
1 row selected.

Example 26-4 Using Function DBMS_XDB.changePrivileges

In this example, user hr connects and uses function changePrivileges to add a new access control entry (ACE) to the ACL, which gives all privileges on resource emp_selby.xml to user oe. Procedure getACLDocument shows that the new ACE was added to the ACL.

CONNECT hr
Password: *************

Connected.

SET SERVEROUTPUT ON

-- Add an ACE giving privileges to user OE
DECLARE
  r        PLS_INTEGER;
  ace      XMLType;
  ace_data VARCHAR2(2000);
BEGIN
  ace_data := '<ace xmlns="http://xmlns.oracle.com/xdb/acl.xsd"
                    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                    xsi:schemaLocation="http://xmlns.oracle.com/xdb/acl.xsd
                                        http://xmlns.oracle.com/xdb/acl.xsd
                                        DAV:http://xmlns.oracle.com/xdb/dav.xsd">
                 <principal>OE</principal>
                 <grant>true</grant>
                 <privilege><all/></privilege>
               </ace>';
  ace := XMLType.createXML(ace_data);
  r := DBMS_XDB.changePrivileges('/public/mydocs/emp_selby.xml', ace);
END;
/
 
PL/SQL procedure successfully completed.

SELECT DBMS_XDB.getACLDocument('/public/mydocs/emp_selby.xml').getCLOBVal()
  FROM DUAL;
 
DBMS_XDB.GETACLDOCUMENT('/PUBLIC/MYDOCS/EMP_SELBY.XML').GETCLOBVAL()
--------------------------------------------------------------------------------
<acl description="Private:All privileges to OWNER only and not accessible to oth
ers" xmlns="http://xmlns.oracle.com/xdb/acl.xsd" xmlns:dav="DAV:" xmlns:xsi="htt
p://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.oracle.
com/xdb/acl.xsd                           http://xmlns.oracle.com/xdb/acl.xsd" s
hared="false">
  <ace>
    <principal>dav:owner</principal>
    <grant>true</grant>
    <privilege>
      <all/>
    </privilege>
  </ace>
  <ace>
    <principal>OE</principal>
    <grant>true</grant>
    <privilege>
      <all/>
    </privilege>
  </ace>
</acl>
 
1 row selected.

Example 26-5 Using Function DBMS_XDB.getPrivileges

In this example, user oe connects and calls DBMS_XDB.getPrivileges, which shows all of the privileges granted to user oe on resource emp_selby.xml.

CONNECT oe/oe
Connected.

SELECT DBMS_XDB.getPrivileges('/public/mydocs/emp_selby.xml') FROM DUAL;

DBMS_XDB.GETPRIVILEGES('/PUBLIC/MYDOCS/EMP_SELBY.XML').GETCLOBVAL()
--------------------------------------------------------------------------------
<privilege xmlns="http://xmlns.oracle.com/xdb/acl.xsd" xmlns:xsi="http://www.w3.
org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.oracle.com/xdb/acl
.xsd http://xmlns.oracle.com/xdb/acl.xsd DAV: http://xmlns.oracle.com/xdb/dav.xs
d" xmlns:xdbacl="http://xmlns.oracle.com/xdb/acl.xsd" xmlns:dav="DAV:">
  <read-properties/>
  <read-contents/>
  <update/>
  <link/>
  <unlink/>
  <read-acl/>
  <write-acl-ref/>
  <update-acl/>
  <resolve/>
  <link-to/>
  <unlink-from/>
  <dav:lock/>
  <dav:unlock/>
</privilege>
 
1 row selected.

DBMS_XDB: Configuration Management

Table 26-3 lists the DBMS_XDB Oracle XML DB configuration management functions and procedures.

Table 26-3 DBMS_XDB: Configuration Management Functions and Procedures

Function/Procedure	Description
`cfg_get`	Returns the configuration information for the current session.
`cfg_refresh`	Refreshes the session configuration information using the current Oracle XML DB configuration file, `xdbconfig.xml`.
`cfg_update`	Updates the Oracle XML DB configuration information. This writes the configuration file, `xdbconfig.xml`.
`getFTPPort`	Returns the current FTP port number.
`getHTTPPort`	Returns the current HTTP port number.
`setFTPPort`	Sets the Oracle XML DB FTP port to the specified port number.
`setHTTPPort`	Sets the Oracle XML DB HTTP port to the specified port number.

The examples in this section illustrate the use of these functions and procedures.

Example 26-6 Using Function DBMS_XDB.cfg_get

In this example, function cfg_get is used to retrieve the Oracle XML DB configuration file, xdbconfig.xml.

CONNECT SYSTEM/MANAGER
Connected.

SELECT DBMS_XDB.cfg_get() FROM DUAL;
 
DBMS_XDB.CFG_GET()
--------------------------------------------------------------------------------
<xdbconfig xmlns="http://xmlns.oracle.com/xdb/xdbconfig.xsd" xmlns:xsi="http://w
ww.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.oracle.com/x
db/xdbconfig.xsd                                     http://xmlns.oracle.com/xdb
/xdbconfig.xsd">
  <sysconfig>
    <acl-max-age>900</acl-max-age>
    <acl-cache-size>32</acl-cache-size>
    <invalid-pathname-chars>,</invalid-pathname-chars>
    <case-sensitive>true</case-sensitive>
    <call-timeout>300</call-timeout>
    <max-link-queue>65536</max-link-queue>
    <max-session-use>100</max-session-use>
    <persistent-sessions>false</persistent-sessions>
    <default-lock-timeout>3600</default-lock-timeout>
    <xdbcore-logfile-path/>
    <xdbcore-log-level>0</xdbcore-log-level>
    <resource-view-cache-size>1048576</resource-view-cache-size>
    <protocolconfig>
      <common>
        . . .
      </common>
      <ftpconfig>
        . . .
      </ftpconfig>
      <httpconfig>
        <http-port>8000</http-port>
        <http-listener>local_listener</http-listener>
        <http-protocol>tcp</http-protocol>
        <max-http-headers>64</max-http-headers>
        <max-header-size>16384</max-header-size>
        <max-request-body>2000000000</max-request-body>
        <session-timeout>6000</session-timeout>
        <server-name>XDB HTTP Server</server-name>
        <logfile-path/>
        <log-level>0</log-level>
        <servlet-realm>Basic realm=&quot;XDB&quot;</servlet-realm>
        <webappconfig>
        . . .
        </webappconfig>
      </httpconfig>
    </protocolconfig>
    <xdbcore-xobmem-bound>1024</xdbcore-xobmem-bound>
    <xdbcore-loadableunit-size>16</xdbcore-loadableunit-size>
  </sysconfig>
</xdbconfig>
 
1 row selected.

Example 26-7 Using Procedure DBMS_XDB.cfg_update

This example illustrates the use of procedure cfg_update. The current configuration is retrieved as an XMLType instance and modified. It is then rewritten using cfg_update.

DECLARE
  configxml    SYS.XMLType;
  configxml2   SYS.XMLType;
BEGIN
  -- Get the current configuration
  configxml := DBMS_XDB.cfg_get();
 
  -- Modify the configuration
  SELECT updateXML(
           configxml,
           '/xdbconfig/sysconfig/protocolconfig/httpconfig/http-port/text()',
           '8000',
           'xmlns="http://xmlns.oracle.com/xdb/xdbconfig.xsd"')
    INTO configxml2 FROM DUAL;
 
  -- Update the configuration to use the modified version
  DBMS_XDB.cfg_update(configxml2);
END;
/
 
PL/SQL procedure successfully completed.

SELECT DBMS_XDB.cfg_get() FROM DUAL;
 
DBMS_XDB.CFG_GET()
--------------------------------------------------------------------------------
<xdbconfig xmlns="http://xmlns.oracle.com/xdb/xdbconfig.xsd" xmlns:xsi="http://w
ww.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.oracle.com/x
db/xdbconfig.xsd                                     http://xmlns.oracle.com/xdb
/xdbconfig.xsd">
  <sysconfig>
    <acl-max-age>900</acl-max-age>
    <acl-cache-size>32</acl-cache-size>
    <invalid-pathname-chars>,</invalid-pathname-chars>
    <case-sensitive>true</case-sensitive>
    <call-timeout>300</call-timeout>
    <max-link-queue>65536</max-link-queue>
    <max-session-use>100</max-session-use>
    <persistent-sessions>false</persistent-sessions>
    <default-lock-timeout>3600</default-lock-timeout>
    <xdbcore-logfile-path/>
    <xdbcore-log-level>0</xdbcore-log-level>
    <resource-view-cache-size>1048576</resource-view-cache-size>
    <protocolconfig>
      <common>
      . . .
      </common>
      <ftpconfig>
      . . .
      </ftpconfig>
      <httpconfig>
        <http-port>8000</http-port>
        . . .
      </httpconfig>
    </protocolconfig>
    <xdbcore-xobmem-bound>1024</xdbcore-xobmem-bound>
    <xdbcore-loadableunit-size>16</xdbcore-loadableunit-size>
  </sysconfig>
</xdbconfig>
 
1 row selected.