Index: includes/database/sqlite/query.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/database/sqlite/query.inc,v
retrieving revision 1.10
diff -u -p -r1.10 query.inc
--- includes/database/sqlite/query.inc	15 May 2010 07:04:21 -0000	1.10
+++ includes/database/sqlite/query.inc	29 Jun 2010 08:12:37 -0000
@@ -12,6 +12,86 @@
  */
 
 /**
+ * SQLite specific implementation of MergeQuery.
+ *
+ * SQLite doesn't support "SELECT ... FOR UPDATE" syntax:
+ * http://www.sqlite.org/cvstrac/wiki?p=UnsupportedSql
+ */
+class MergeQuery_sqlite extends MergeQuery {
+  public function execute() {
+    // If validation fails, simply return NULL.
+    // Note that validation routines in preExecute() may throw exceptions instead.
+    if (!$this->preExecute()) {
+      return NULL;
+    }
+
+    // Wrap multiple queries in a transaction, if the database supports it.
+    $transaction = $this->connection->startTransaction();
+
+    try {
+      // Manually check if the record already exists.
+      $select = $this->connection->select($this->table);
+      $select->addExpression('1');
+      foreach ($this->keyFields as $field => $value) {
+        $select->condition($field, $value);
+      }
+
+      $sql = (string) $select;
+      $arguments = $select->getArguments();
+
+      // If there are no existing records, run an insert query.
+      if (!$this->connection->query($sql, $arguments)->fetchField()) {
+        $insert_fields = $this->insertFields + $this->keyFields;
+        try {
+          $this->connection->insert($this->table, $this->queryOptions)->fields($insert_fields)->execute();
+          return MergeQuery::STATUS_INSERT;
+        }
+        catch (Exception $e) {
+          // The insert query failed, maybe it's because a racing insert query
+          // beat us in inserting the same row. Retry the select query, if it
+          // returns a row, ignore the error and continue with the update
+          // query below.
+          if (!$this->connection->query($sql, $arguments)->fetchField()) {
+            throw $e;
+          }
+        }
+      }
+
+      // Proceed with an update query if a row was found.
+      if ($this->updateFields) {
+        $update_fields = $this->updateFields;
+      }
+      else {
+        $update_fields = $this->insertFields;
+        // If there are no exclude fields, this is a no-op.
+        foreach ($this->excludeFields as $exclude_field) {
+          unset($update_fields[$exclude_field]);
+        }
+      }
+      if ($update_fields || $this->expressionFields) {
+        // Only run the update if there are fields or expressions to update.
+        $update = $this->connection->update($this->table, $this->queryOptions)->fields($update_fields);
+        foreach ($this->keyFields as $field => $value) {
+          $update->condition($field, $value);
+        }
+        foreach ($this->expressionFields as $field => $expression) {
+          $update->expression($field, $expression['expression'], $expression['arguments']);
+        }
+        $update->execute();
+        return MergeQuery::STATUS_UPDATE;
+      }
+    }
+    catch (Exception $e) {
+      // Something really wrong happened here, bubble up the exception to the
+      // caller.
+      $transaction->rollback();
+      throw $e;
+    }
+    // Transaction commits here where $transaction looses scope.
+  }
+}
+
+/**
  * SQLite specific implementation of InsertQuery.
  *
  * We ignore all the default fields and use the clever SQLite syntax: