Index: xwiki-platform-core/xwiki-core/src/main/java/com/xpn/xwiki/store/XWikiHibernateBaseStore.java
===================================================================
--- xwiki-platform-core/xwiki-core/src/main/java/com/xpn/xwiki/store/XWikiHibernateBaseStore.java	(revision 10917)
+++ xwiki-platform-core/xwiki-core/src/main/java/com/xpn/xwiki/store/XWikiHibernateBaseStore.java	(working copy)
@@ -154,21 +154,45 @@
      * 
      * @throws org.hibernate.HibernateException
      */
-    private void initHibernate() throws HibernateException
+    private void initHibernate(XWikiContext context) throws HibernateException
     {
         // Load Configuration and build SessionFactory
         String path = getPath();
+        Configuration cfg = new Configuration();
         if (path != null)
-            setConfiguration((new Configuration()).configure(new File(path)));
+            cfg.configure(new File(path));
         else {
             URL hiburl = getHibUrl();
             if (hiburl != null)
-                setConfiguration(new Configuration().configure(hiburl));
+                cfg.configure(hiburl);
             else
-                setConfiguration(new Configuration().configure());
+                cfg.configure();
         }
+        
+        XWiki wiki = context.getWiki();
+        if (wiki!=null && wiki.Param("xwiki.db")!=null 
+                       && !wiki.isVirtualMode()) {
+           // substitute default db name to configurated.
+           // note, that we can't call getSchemaFromWikiName() here,
+           // becouse it ask getDatabaseProduct() which use connection
+           // which must be opened.  But here (before connection init)
+           // we have no opened connections yet.
+           String schemaName;
+           if ( context.isMainWiki() ) {
+               schemaName = wiki.Param("xwiki.db");
+           } else {
+               schemaName = context.getDatabase().replace('-','_');
+           }
+           String dialect = cfg.getProperty(Environment.DIALECT);
+           if ("org.hibernate.dialect.MySQLDialect".equals(dialect)) {
+              cfg.setProperty(Environment.DEFAULT_CATALOG,schemaName);
+           } else {
+              cfg.setProperty(Environment.DEFAULT_SCHEMA,schemaName);
+           }
+        }
+        setConfiguration(cfg);
 
-        setSessionFactory(getConfiguration().buildSessionFactory());
+        setSessionFactory(cfg.buildSessionFactory());
     }
 
     /**
@@ -331,12 +355,32 @@
 
         DatabaseProduct databaseProduct = getDatabaseProductName(context);
 
-        if (databaseProduct == DatabaseProduct.DERBY) {
-            return context.isMainWiki(wikiName) ? "APP" : wikiName.replace('-', '_');
-        } else if (databaseProduct == DatabaseProduct.HSQLDB) {
-            return context.isMainWiki(wikiName) ? "PUBLIC" : wikiName.replace('-', '_');
-        } else
-            return wikiName.replace('-', '_');
+        String retval;
+        XWiki  wiki = context.getWiki();
+        if (context.isMainWiki(wikiName)) {
+           String xwikidb = wiki.Param("xwiki.db");
+           if (xwikidb!=null) {
+             retval=xwikidb;
+           }else{
+             if (databaseProduct == DatabaseProduct.DERBY) {
+                retval = "APP";
+             } else if (databaseProduct == DatabaseProduct.HSQLDB) {
+                retval = "PUBLIC";
+             } else {
+               retval = wikiName.replace('-','_');
+             }
+           }
+        } else {
+           // virtual
+           retval = wikiName.replace('-','_');
+        }
+
+        if (wiki.isVirtualMode()) {
+          String prefix = wiki.Param("xwiki.virtual.db.prefix","");
+          retval = prefix + retval;
+        }
+
+        return retval;
     }
 
     /**
@@ -514,7 +558,7 @@
             synchronized (this) {
                 if (getSessionFactory() == null) {
 
-                    initHibernate();
+                    initHibernate(context);
                     /* Check Schema */
                     if (getSessionFactory() != null) {
                         updateSchema(context);