diff --git a/lib/schema.php b/lib/schema.php
index f6543a21b1..04bd2d1d94 100644
--- a/lib/schema.php
+++ b/lib/schema.php
@@ -234,7 +234,7 @@ class Schema
      */
     function appendUniqueKeyDef(array &$sql, $name, array $def)
     {
-        $sql[] = "UNIQUE $key " . $this->buildIndexList($def);
+        $sql[] = "UNIQUE $name " . $this->buildIndexList($def);
     }
 
     /**
@@ -487,59 +487,81 @@ class Schema
             }
         }
 
-        $cur = array_keys($old['fields']);
-        $new = array_keys($def['fields']);
-
-        $toadd  = array_diff($new, $cur);
-        $todrop = array_diff($cur, $new);
-        $same   = array_intersect($new, $cur);
-        $tomod  = array();
-
-        // Find which fields have actually changed definition
-        // in a way that we need to tweak them for this DB type.
-        foreach ($same as $name) {
-            $curCol = $old['fields'][$name];
-            $newCol = $cur['fields'][$name];
-
-            if (!$this->columnsEqual($curCol, $newCol)) {
-                $tomod[] = $name;
-            }
-        }
+        // @fixme check if not present
+        $fields = $this->diffArrays($old['fields'], $def['fields'], array($this, 'columnsEqual'));
+        $uniques = $this->diffArrays($old['unique keys'], $def['unique keys']);
+        $indexes = $this->diffArrays($old['indexes'], $def['indexes']);
 
+        /*
         if (count($toadd) + count($todrop) + count($tomod) == 0) {
             // nothing to do
             return true;
         }
+         */
 
         // For efficiency, we want this all in one
         // query, instead of using our methods.
 
         $phrase = array();
 
-        foreach ($toadd as $columnName) {
+        foreach ($uniques['del'] + $uniques['mod'] as $keyName) {
+            $this->appendAlterDropUnique($phrase, $keyName);
+        }
+
+        foreach ($fields['add'] as $columnName) {
             $this->appendAlterAddColumn($phrase, $columnName,
                     $def['fields'][$columnName]);
         }
 
-        foreach ($todrop as $columnName) {
+        foreach ($fields['mod'] as $columnName) {
             $this->appendAlterModifyColumn($phrase, $columnName,
                     $old['fields'][$columnName],
                     $def['fields'][$columnName]);
         }
 
-        foreach ($tomod as $columnName) {
+        foreach ($fields['del'] as $columnName) {
             $this->appendAlterDropColumn($phrase, $columnName);
         }
 
-        $sql = 'ALTER TABLE ' . $tableName . ' ' . implode(', ', $phrase);
-
-        $res = $this->conn->query($sql);
-
-        if (PEAR::isError($res)) {
-            throw new Exception($res->getMessage());
+        foreach ($uniques['mod'] + $uniques['add'] as $keyName) {
+            $this->appendAlterAddUnique($phrase, $keyName, $def['unique keys'][$keyName]);
         }
 
-        return true;
+        $sql = 'ALTER TABLE ' . $tableName . ' ' . implode(",\n", $phrase);
+
+        return array($sql);
+    }
+
+    function diffArrays($old, $new, $compareCallback=null)
+    {
+
+        $oldKeys = array_keys($old ? $old : array());
+        $newKeys = array_keys($new ? $new : array());
+
+        $toadd  = array_diff($newKeys, $oldKeys);
+        $todrop = array_diff($oldKeys, $newKeys);
+        $same   = array_intersect($newKeys, $oldKeys);
+        $tomod  = array();
+        $tokeep = array();
+
+        // Find which fields have actually changed definition
+        // in a way that we need to tweak them for this DB type.
+        foreach ($same as $name) {
+            if ($compareCallback) {
+                $same = call_user_func($compareCallback, $old[$name], $new[$name]);
+            } else {
+                $same = ($old[$name] != $new[$name]);
+            }
+            if ($same) {
+                $tokeep[] = $name;
+                continue;
+            }
+            $tomod[] = $name;
+        }
+        return array('add' => $toadd,
+                     'del' => $todrop,
+                     'mod' => $tomod,
+                     'keep' => $tokeep);
     }
 
     /**
@@ -587,6 +609,19 @@ class Schema
         $phrase[] = 'DROP COLUMN ' . $this->quoteIdentifier($columnName);
     }
 
+    function appendAlterAddUnique(array &$phrase, $keyName, array $def)
+    {
+        $sql = array();
+        $sql[] = 'ADD';
+        $this->appendUniqueKeyDef($sql, $keyName, $def);
+        $phrase[] = implode(' ', $sql);'ADD CONSTRAINT ' . $keyName;
+    }
+
+    function appendAlterDropUnique(array &$phrase, $keyName)
+    {
+        $phrase[] = 'DROP CONSTRAINT ' . $keyName;
+    }
+
     /**
      * Quote a db/table/column identifier if necessary.
      *
diff --git a/scripts/dumpschema.php b/scripts/dumpschema.php
index c0bf84f7c4..3c23636383 100644
--- a/scripts/dumpschema.php
+++ b/scripts/dumpschema.php
@@ -23,9 +23,15 @@ define('INSTALLDIR', realpath(dirname(__FILE__) . '/..'));
 $helptext = <<<END_OF_CHECKSCHEMA_HELP
 Attempt to pull a schema definition for a given table.
 
+  --all     run over all defined core tables
+  --diff    do a raw text diff between the expected and live table defs
+  --update  dump SQL that would be run to update or create this table
+  --build   dump SQL that would be run to create this table fresh
+
+
 END_OF_CHECKSCHEMA_HELP;
 
-$longoptions = array('diff', 'all', 'build');
+$longoptions = array('diff', 'all', 'build', 'update');
 require_once INSTALLDIR.'/scripts/commandline.inc';
 
 function indentOptions($indent)
@@ -121,6 +127,21 @@ function dumpBuildTable($tableName)
     echo "\n";
 }
 
+function dumpEnsureTable($tableName)
+{
+    echo "-- \n";
+    echo "-- $tableName\n";
+    echo "-- \n";
+
+    $schema = Schema::get();
+    $def = getCoreSchema($tableName);
+    $sql = $schema->buildEnsureTable($tableName, $def);
+    $sql[] = '';
+
+    echo implode(";\n", $sql);
+    echo "\n";
+}
+
 function showDiff($a, $b)
 {
     $fnameA = tempnam(sys_get_temp_dir(), 'defined-diff-a');
@@ -156,6 +177,8 @@ if (count($args)) {
             showDiff($defined, $detected);
         } else if (have_option('build')) {
             dumpBuildTable($tableName);
+        } else if (have_option('update')) {
+            dumpEnsureTable($tableName);
         } else {
             dumpTable($tableName, true);
         }