build sql as a component - this will help ensure there is only one copy

sql/transaction.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef SQL_TRANSACTION_H_
 #define SQL_TRANSACTION_H_
 #pragma once
 
 #include "base/basictypes.h"
+#include "sql/sql_export.h"
 
 namespace sql {
 
 class Connection;
 
-class Transaction {
+class SQL_EXPORT Transaction {
  public:
   // Creates the scoped transaction object. You MUST call Begin() to begin the
   // transaction. If you have begun a transaction and not committed it, the
   // constructor will roll back the transaction. If you want to commit, you
   // need to manually call Commit before this goes out of scope.
   explicit Transaction(Connection* connection);
   ~Transaction();
 
   // Returns true when there is a transaction that has been successfully begun.
   bool is_open() const { return is_open_; }
@@ skipping 22 matching lines @@
   // True when the transaction is open, false when it's already been committed
   // or rolled back.
   bool is_open_;
 
   DISALLOW_COPY_AND_ASSIGN(Transaction);
 };
 
 }  // namespace sql
 
 #endif  // SQL_TRANSACTION_H_