don't use $r == DB_OK checks, because they cause PHP warnings when $r is DB_Error object.

turned on field case portability for Oracle.
escaped SQL wildcards in search() method
handle nickname changes in modify() method. Users could get DB error when new nickname is already in use
make search case insensitive in serch() method.

functions/abook_database.php

@@ -3,6 +3,17 @@
 /**
  * abook_database.php
  *
+ * Supported database schema
+ * <pre>
+ *  owner varchar(128) NOT NULL
+ *  nickname varchar(16) NOT NULL
+ *  firstname varchar(128) 
+ *  lastname varchar(128)
+ *  email varchar(128) NOT NULL
+ *  label varchar(255)
+ *  PRIMARY KEY (owner,nickname)
+ * </pre>
+ *
  * @copyright &copy; 1999-2006 The SquirrelMail Project Team
  * @license http://opensource.org/licenses/gpl-license.php GNU Public License
  * @version $Id$
@@ -165,6 +176,13 @@ class abook_database extends addressbook_backend {
         }
 
         $this->dbh = $dbh;
+
+        /**
+         * field names are lowercased.
+         * We use unquoted identifiers and they use upper case in Oracle
+         */
+        $this->dbh->setOption('portability', DB_PORTABILITY_LOWERCASE);
+
         return true;
     }
 
@@ -180,8 +198,11 @@ class abook_database extends addressbook_backend {
 
     /**
      * Search the database
+     *
+     * Backend supports only * and ? wildcards. Complex eregs are not supported.
+     * Search is case insensitive.
      * @param string $expr search expression
-     * @return array search results
+     * @return array search results. boolean false on error
      */
     function search($expr) {
         $ret = array();
@@ -198,15 +219,26 @@ class abook_database extends addressbook_backend {
         if ($expr=='*' && ! $this->listing)
             return array();
 
-        /* Make regexp from glob'ed expression  */
+        /* lowercase expression in order to make it case insensitive */
+        $expr = strtolower($expr);
+
+        /* escape SQL wildcards */
+        $expr = str_replace('_', '\\_', $expr);
+        $expr = str_replace('%', '\\%', $expr);
+
+        /* Convert wildcards to SQL syntax  */
         $expr = str_replace('?', '_', $expr);
         $expr = str_replace('*', '%', $expr);
         $expr = $this->dbh->quoteString($expr);
         $expr = "%$expr%";
 
+        /* create escape expression */
+        $escape = 'ESCAPE \'' . $this->dbh->quoteString('\\') . '\'';
+    
         $query = sprintf("SELECT * FROM %s WHERE owner='%s' AND " .
-                         "(firstname LIKE '%s' OR lastname LIKE '%s')",
-                         $this->table, $this->owner, $expr, $expr);
+                         "(LOWER(firstname) LIKE '%s' %s OR LOWER(lastname) LIKE '%s' %s)",
+                         $this->table, $this->owner, $expr, $escape, $expr, $escape);
+
         $res = $this->dbh->query($query);
 
         if (DB::isError($res)) {
@@ -337,13 +369,13 @@ class abook_database extends addressbook_backend {
 
          /* Do the insert */
          $r = $this->dbh->simpleQuery($query);
-         if ($r == DB_OK) {
-             return true;
+ 
+         /* Check for errors */
+         if (DB::isError($r)) {
+             return $this->set_error(sprintf(_("Database error: %s"),
+                                             DB::errorMessage($r)));
          }
-
-         /* Fail */
-         return $this->set_error(sprintf(_("Database error: %s"),
-                                         DB::errorMessage($r)));
+         return true;
     }
 
     /**
@@ -375,13 +407,13 @@ class abook_database extends addressbook_backend {
 
         /* Delete entry */
         $r = $this->dbh->simpleQuery($query);
-        if ($r == DB_OK) {
-            return true;
-        }
 
-        /* Fail */
-        return $this->set_error(sprintf(_("Database error: %s"),
-                                         DB::errorMessage($r)));
+        /* Check for errors */
+        if (DB::isError($r)) {
+            return $this->set_error(sprintf(_("Database error: %s"),
+                                            DB::errorMessage($r)));
+        }
+        return true;
     }
 
     /**
@@ -405,6 +437,16 @@ class abook_database extends addressbook_backend {
             return $this->set_error(sprintf(_("User \"%s\" does not exist"),$alias));
         }
 
+        /* make sure that new nickname is not used */
+        if (strtolower($alias) != strtolower($userdata['nickname'])) {
+            /* same check as in add() */
+            $ret = $this->lookup($userdata['nickname']);
+            if (!empty($ret)) {
+                $error = sprintf(_("User '%s' already exist."), $ret['nickname']);
+                return $this->set_error($error);
+            }
+        }
+
         /* Create query */
         $query = sprintf("UPDATE %s SET nickname='%s', firstname='%s', ".
                          "lastname='%s', email='%s', label='%s' ".
@@ -420,13 +462,13 @@ class abook_database extends addressbook_backend {
 
         /* Do the insert */
         $r = $this->dbh->simpleQuery($query);
-        if ($r == DB_OK) {
-            return true;
-        }
 
-        /* Fail */
-        return $this->set_error(sprintf(_("Database error: %s"),
-                                        DB::errorMessage($r)));
+        /* Check for errors */
+        if (DB::isError($r)) {
+            return $this->set_error(sprintf(_("Database error: %s"),
+                                            DB::errorMessage($r)));
+        }
+        return true;
     }
 } /* End of class abook_database */