Effecting constraint magic rewriting on a query with the multiset
version of the relational algebric theta-semijoin operator
    1.
    发明授权
    Effecting constraint magic rewriting on a query with the multiset version of the relational algebric theta-semijoin operator 失效
    使用关系代数theta-semijoin运算符的多集版本对查询执行约束魔法重写

    公开(公告)号:US6061676A

    公开(公告)日:2000-05-09

    申请号:US862906

    申请日:1997-05-23

    IPC分类号: G06F17/30

    摘要: An equivalence rule having the multiset version of the relational algebraic theta-semijoin operator is used in effectuating Constraint Magic rewriting on a computer programming language query having non-equality, as well as equality, predicates. In particular, the rule effectuates Constraint Magic rewriting for a single join. When applied repeatedly on a sequence of joins, Constraint Magic rewriting is effectuated for a single block query. The rule may be used to generate relational algebraic expressions to optimize or determine the equivalency of queries. Cost estimates for alternative ways of evaluating a complex query can be efficiently computed. Based on these computed cost estimates, the least costly implementation of a complex query is determined.

    摘要翻译: 具有关系代数theta-semijoin算子的多重版本的等价规则被用于在具有不相等性以及相等的谓词的计算机编程语言查询上实现约束魔法重写。 特别地,规则对单个连接实施约束魔法重写。 当对一系列连接重复应用时,对于单个块查询实现了约束魔法重写。 该规则可用于生成关系代数表达式以优化或确定查询的等价性。 可以有效地计算评估复杂查询的替代方法的成本估算。 基于这些计算的成本估计,确定复杂查询的成本最低的实现。

    Optimization of queries using relational algebraic theta-semijoin
operator
    2.
    发明授权
    Optimization of queries using relational algebraic theta-semijoin operator 失效
    使用关系代数theta-semijoin算子优化查询

    公开(公告)号:US06032144A

    公开(公告)日:2000-02-29

    申请号:US862459

    申请日:1997-05-23

    IPC分类号: G06F17/30

    摘要: A collection of equivalence rules involving the multiset version of the relational algebraic theta-semijoin operator is used to generate relational algebraic expressions equivalent to a computer programming language query. These expressions may be employed as a search space which is utilized by, for example, optimizing software or software that determines the equivalency of queries. Cost formulas for the multiset version of the theta-semijoin operator may be used in computing cost estimates for the generated expressions. Based on these computed cost estimates, the least costly implementation of a complex query is determined. Thus, queries are cost-based optimized on both a local and global basis by use of the relational algebraic theta-semijoin operator.

    摘要翻译: 使用涉及关系代数theta-semijoin算子的多集版本的等价规则的集合来生成与计算机编程语言查询相当的关系代数表达式。 这些表达式可以被用作通过例如优化确定查询的等价性的软件或软件来利用的搜索空间。 θ-semijoin运算符的多集版本的成本公式可用于计算生成表达式的成本估计。 基于这些计算的成本估计,确定复杂查询的成本最低的实现。 因此,查询是通过使用关系代数theta-semijoin运算符在本地和全局基础上进行成本优化的。

    Cost-based maintenance of materialized views
    3.
    发明授权
    Cost-based maintenance of materialized views 失效
    物质视图的成本维护

    公开(公告)号:US6026390A

    公开(公告)日:2000-02-15

    申请号:US890194

    申请日:1997-07-09

    IPC分类号: G06F17/30

    摘要: A method of incrementally maintaining a first materialized view of data in a database, by means of an additional materialized view, first determines whether a cost in time of incrementally maintaining the first materialized view with the additional materialized view is less than the cost of incrementally maintaining the first materialized view without the additional materialized view. The method creates the additional materialized view only if the cost in time is less therewith. Determining whether the cost of employing an additional materialized view is less includes using an expression directed acyclic graph that corresponds to the first materialized view. Another method of determining whether the cost is less includes pruning an expression directed acyclic graph to produce a single expression tree, and using the single expression tree to determine whether the cost is less. Both the expression directed acyclic graph and the single expression tree contain equivalence nodes. One or more possible materialized views are selected by marking the equivalence nodes, and materializing one or more views corresponding to the marked equivalence nodes. One or more possible materialized views are also selected by determining which of the views, if materialized, would result in a lowest cost of incrementally maintaining the first materialized view. The method is also used to reduce the cost in time of maintaining a first materialized view employed to check an integrity constraint of the database.

    摘要翻译: 通过附加的物化视图来逐步维护数据库中的数据的第一物化视图的方法首先确定用附加物化视图逐步维持第一物化视图的时间成本是否小于增量维护的成本 第一个物化视图没有附加的物化视图。 该方法只有在时间上的成本较低时才创建附加的物化视图。 确定采用附加物化视图的成本是否较小包括使用对应于第一实例化视图的表达式有向无环图。 确定成本是否较小的另一种方法包括修剪表达式非循环图以产生单个表达式树,并使用单个表达式树来确定成本是否较小。 表达式非循环图和单个表达式树都包含等价节点。 通过标记等价节点以及实现对应于标记的等价节点的一个或多个视图来选择一个或多个可能的物化视图。 还可以通过确定哪些视图(如果实现)将导致递增地维持第一实例化视图的最低成本来选择一个或多个可能的物化视图。 该方法还用于降低维护用于检查数据库的完整性约束的第一物化视图的时间成本。

    System and method for aging versions of data in a main memory database
    4.
    发明授权
    System and method for aging versions of data in a main memory database 失效
    主内存数据库中数据老化版本的系统和方法

    公开(公告)号:US6125371A

    公开(公告)日:2000-09-26

    申请号:US914744

    申请日:1997-08-19

    IPC分类号: G06F17/30

    摘要: For use with a database of data records stored in a memory, a system and method for increasing a memory capacity and a memory database employing the system or the method. The system includes: (1) a time stamping controller that assigns a time stamp to transactions to be performed on the database, the time stamp operates to preserve an order of the transactions, (2) a versioning controller that creates multiple versions of ones of the data records affected by the transactions that are update transactions and (3) an aging controller, which is associated with each of the time stamping and versioning controllers, that monitors a measurable characteristic of the memory and deletes ones of the multiple versions of the ones of the data records in response to the time stamp and the measurable characteristic thereby to increase memory capacity.

    摘要翻译: 用于存储在存储器中的数据记录的数据库,用于增加存储器容量的系统和方法以及采用该系统或方法的存储器数据库。 该系统包括:(1)时间戳控制器,为在数据库上执行的事务分配时间戳,时间戳操作以保持事务的顺序,(2)版本控制器,其创建多个版本的 由更新事务的事务影响的数据记录和(3)与每个时间戳和版本控制器相关联的老化控制器,其监视存储器的可测量特性并删除其中的一个版本 的数据记录,以响应于时间戳和可测量的特性,从而增加存储器容量。

    FINE-GRAINED ACCESS CONTROL IN A DATABASE BY PREVENTING INFORMATION LEAKAGE AND REMOVING REDUNDANCY
    6.
    发明申请
    FINE-GRAINED ACCESS CONTROL IN A DATABASE BY PREVENTING INFORMATION LEAKAGE AND REMOVING REDUNDANCY 失效
    通过防止信息泄漏和删除冗余来进行数据库中的细粒度访问控制

    公开(公告)号:US20080071785A1

    公开(公告)日:2008-03-20

    申请号:US11468928

    申请日:2006-08-31

    IPC分类号: G06F17/30

    摘要: Fine-grained access control for querying a database with low overhead and safety plans. In a view placement approach, base relations of the query expression are replaced by views that are appropriate for the particular user. Information leakage via UDF pushing, exception processing, and error messages can be prevented by generating safe plans. An existing query optimizer can be modified to perform redundancy removal and safe plan implementation. Subsumption testing available in materialized view matching can be exploited by the query optimizer. Authorization inference is exploited to generate safe plans.

    摘要翻译: 用于以低开销和安全计划查询数据库的细粒度访问控制。 在视图放置方法中,查询表达式的基础关系被替换为适合特定用户的视图。 可以通过生成安全计划来防止通过UDF推送,异常处理和错误消息的信息泄漏。 可以修改现有的查询优化器,以执行冗余删除和安全计划实施。 查询优化器可以利用实体​​化视图匹配中的可用度量测试。 利用授权推理来制定安全计划。

    Method and apparatus for detecting and recovering from data corruption of a database via read prechecking and deferred maintenance of codewords
    8.
    发明授权
    Method and apparatus for detecting and recovering from data corruption of a database via read prechecking and deferred maintenance of codewords 有权
    用于通过读取预检和代码字的延迟维护来检测和恢复数据库的数据损坏的方法和装置

    公开(公告)号:US06374264B1

    公开(公告)日:2002-04-16

    申请号:US09207926

    申请日:1998-12-09

    IPC分类号: G06F1730

    摘要: A method of detecting and recovering from data corruption of a database is characterized by the step of protecting data of the database with codewords, one codeword for each region of the database; and verifying that a codeword matches associated data before the data is read from the database to prevent transaction-carried corruption. A deferred maintenance scheme is recommended for the codewords protecting the database such that the method of detecting and recovering from data corruption of a database may comprise the steps of protecting data of the database with codewords, one codeword for each region of the database; and asynchronously maintaining the codewords to improve concurrency of the database. Moreover, the database may be audited by using the codewords and noting them in a table and protecting regions of the database with latches. Once codeword values are computed and checked against noted values in memory, a flush can cause codewords from outstanding log records to be applied to the stored codeword table.

    摘要翻译: 一种从数据库的数据损坏中检测和恢复的方法的特征在于利用码字保护数据库的数据的步骤,数据库的每个区域的一个码字; 并且在从数据库读取数据之前验证码字匹配相关联的数据以防止交易携带的损坏。 对于保护数据库的代码字,建议使用延迟维护方案,以便检测和恢复数据库的数据损坏的方法可以包括以下代码字来保护数据库的数据的步骤,数据库的每个区域的一个代码字; 并且异步地维护码字以改善数据库的并发性。 此外,可以通过使用码字来审核数据库,并在表中注明数据库,并用锁存器保护数据库的区域。 一旦根据存储器中的标记值计算和检查码字值,则刷新可以使来自未完成的日志记录的码字被应用于存储的码字表。

    Garbage collection in object oriented databases using transactional cyclic reference counting
    9.
    发明授权
    Garbage collection in object oriented databases using transactional cyclic reference counting 有权
    使用事务循环引用计数的面向对象数据库中的垃圾收集

    公开(公告)号:US06363403B1

    公开(公告)日:2002-03-26

    申请号:US09345826

    申请日:1999-06-30

    IPC分类号: G06F1730

    摘要: A reference counting a garbage collection process employs a reference counting technique in which only the “last” detected strong pointer is followed to an object. Moreover, no assumptions are made about the phase locking used in the transaction and strict WAL is not followed. Indeed, a relatively restricted local traversal of the object graph is employed which leads to higher efficiency. Furthermore, in a client-server arrangement, updates made by a transaction running at the client may be reflected at the server after the transaction ends, and the updates are not required to be forced to the server before the end of the transaction.

    摘要翻译: 对垃圾收集过程进行计数的参考采用一种引用计数技术,其中只有“最后”检测到的强指针被跟随到对象。 此外,没有对事务中使用的锁相进行假设,并且不遵循严格的WAL。 实际上,采用对象图的相对受限的局部遍历,这导致更高的效率。 此外,在客户端 - 服务器安排中,在事务结束之后,在客户机上运行的事务进行的更新可以在服务器处反映,并且在事务结束之前不需要将更新强制到服务器。

    System and method for physically versioning data in a main memory
database
    10.
    发明授权
    System and method for physically versioning data in a main memory database 失效
    在主内存数据库中物理版本化数据的系统和方法

    公开(公告)号:US6122645A

    公开(公告)日:2000-09-19

    申请号:US2635

    申请日:1998-01-05

    IPC分类号: G06F17/30

    摘要: For use with a database of data records organized into components, the database stored in a memory, a processing system for, and method of, physically versioning the database. In one embodiment, the processing system includes: (1) a component copier that creates a physical copy of an original component to be affected by an update transaction to be applied to the database, and that causes pointers in nodes of the physical copy to point to other nodes in the physical copy, (2) a data updater, associated with the component copier, that applies the update transaction to the physical copy to create therefrom a new physical version, the original component remaining unaffected by the update transaction and (3) a pointer updater, associated with the data updated, that employs an atomic word write to revise a component pointer, associated with the database, to cause the pointer to point to the new physical version.

    摘要翻译: 为了与组织成组件的数据记录的数据库一起使用,存储在内存中的数据库,处理系统以及对数据库进行物理版本化的方法。 在一个实施例中,处理系统包括:(1)组件复印机,其创建将要被应用于数据库的更新事务影响的原始组件的物理副本,并且使物理副本的节点中的指针指向 到物理副本中的其他节点,(2)与组件复印机相关联的数据更新器,将更新事务应用于物理副本以从其创建新的物理版本,原始组件不受更新事务的影响,(3 )与更新的数据相关联的指针更新器,其使用原子字写入来修改与数据库相关联的组件指针,以使指针指向新的物理版本。