Sql server mobile also provides multiple - connection access to a database , multiple - column indexes and matching index limits , transaction support , referential integrity , 128 - bit file - level encryption and password protection , and a query optimizer Sql server mobile还提供对数据库的多连接访问、多列索引和匹配的索引限制、事务支持、引用完整性、 128位文件级加密以及密码保护和查询优化器。