摘要:
A platform (referred to herein as Extensible Application Platform, or XAP) for developing extensible business applications. In one set of embodiments, XAP can include an Extensible Markup Language (XML) based application model that is designed to support a high degree of application extensibility. For example, the XAP application model can support declarative definition of application semantics, separation of application data and metadata, and a flexible type system that allows constraints and calculations (e.g., XQuery constraints and calculations) for a data object instance (e.g., an XML document) to change over time. In certain embodiments, the XAP application model can be implemented via a server-side database/application engine that is configured to interoperate with a spreadsheet-like, client-side user interface. Using the spreadsheet-like UI, a non-programmer can build, customize, and run an application workflow that operates on top of a shared database like a traditional business application.
摘要:
A compact binary encoding technique for information that is logically hierarchically structured, such as XML data, maintains all of the features of XML data in a useable form, such as the hierarchical structure underlying the data. Hence, data encoded in this format can undergo XML-based processing on-the-fly as it is being received or fetched, as if the data was being processed linearly in its textual character-based format. Processing of data encoded in this format can begin without having to wait for and decode the entire data set. The overhead due to XML tags is significantly minimized. The encoded data can be processed more efficiently because the data is pre-parsed. Values may be stored in their native type formats and, therefore, processing of the encoded data avoids costly type conversions. Further, any available structural constraint information can be effectively exploited.
摘要:
A platform (referred to herein as Extensible Application Platform, or XAP) for developing extensible business applications. In one set of embodiments, XAP can include an Extensible Markup Language (XML) based application model that is designed to support a high degree of application extensibility. For example, the XAP application model can support declarative definition of application semantics, separation of application data and metadata, and a flexible type system that allows constraints and calculations (e.g., XQuery constraints and calculations) for a data object instance (e.g., an XML document) to change over time. In certain embodiments, the XAP application model can be implemented via a server-side database/application engine that is configured to interoperate with a spreadsheet-like, client-side user interface. Using the spreadsheet-like UI, a non-programmer can build, customize, and run an application workflow that operates on top of a shared database like a traditional business application.
摘要:
Techniques are provided for changing data for an XML construct in an SQL/XML compliant database management system (DBMS). The DBMS allows instances of XML type to represent XML constructs, such as XML documents, XML elements, XML attributes, and fragments of XML documents. An SQL statement is received that includes an XML operator that operates on a particular component in an instance of XML type. During execution of the SQL statement, the XML operator is evaluated by modifying content for the component without modifying the entire instance. For example, an XML delete operator deletes the particular component from the instance. Other XML operators include an insert operator, an insert-before operator, an append-child operator, and an update operator. During execution, these operators may be rewritten to operate on existing SQL constructs, or evaluated by updating only some of the existing SQL constructs, or both.
摘要:
Techniques are provided for performing OID-to-VMA translations during runtime. Vector registers are used to implement a “software TLB” to perform OID-to-VMA translations. Runtime dereferencing is performed using one or more vector registers to compare each OID that needs to be dereferenced against a set of cached OIDs. When a cached OID matches the OID being dereferenced, the VMA of the cached OID is retrieved from cache. Buffer cache items may be pinned during the period in which the software TLB stores entries for the items. The cache of OID translation information may be single or multi-leveled, and may be partially or completely stored in registers within a processor. When stored in registers, the translation information may be spilled out of the register, and reloaded into the register, as the register is needed for other purposes.
摘要:
Techniques are described for unifying static and dynamic compiler optimizations in source code bases. In an embodiment, a first compiler compiles source code of a target function to generate ahead-of-time (AOT) compiled machine code. A second compiler compiles the source code to generate an intermediate representation (IR) of the target function. In response to determining that the target function should be just-in-time (JIT) compiled, the AOT-compiled machine code for the target function is linked to the IR of the target function. During runtime, a physical processor executes AOT-compiled machine code of an executable program. When the target function is encountered for the first time, a JIT compiler is invoked. The JIT compiler generates JIT-compiled machine code for the target function. The physical processor executes the JIT-compiled machine code in place of the AOT-compiled machine code for the target function.
摘要:
A method and storage media for performing access resolution using ACL types is provided. Under an AND semantic, an intersection set formed from the types of multiple ACLs protecting a resource may be utilized to efficiently determine whether a request for a privilege to access the resource is granted or denied. If the privilege is not a member of the intersection set, the privilege cannot be granted. A union set may be used for an OR semantic. A global ACL type may represent all privileges system-wide or application-wide. A global ACL may represent a system-wide or application-wide access policy. A conjunction of a global ACL and a regular ACL may be stored in a cache. The union set, intersection set, or access resolution may also be cached for subsequent request processing.
摘要:
Techniques are provided for accessing data stored in a database. According to one technique, an application makes one or more calls to an operating system to access a file. The operating system includes routines that implement an operating system file system. The one or more calls are made to the routines that implement the operating system file system. In response to the one or more calls, one or more database commands are issued to a database server that manages the database. The database server executes the database commands to retrieve the data from the database. The file is generated from the data, and provided to the application.
摘要:
Techniques are provided for performing file operations. According to one technique, a file system interface is exposed to applications. The file system interface includes routines for saving and retrieving files. Calls to perform a plurality of file operations are received through the file system interface. The plurality of file operations are performed as a single transaction by performing the steps of: if all file operations of the plurality of file operations are completed without a failure, then making permanent all changes made by the plurality of file operations; and if any file operations of the plurality of file operations fail, then undoing all changes made by all of the plurality of file operations.
摘要:
A method and mechanism are provided for creating, maintaining, and using a hierarchical index to efficiently access information in a relational system based on a pathnames, thus emulating a hierarchically organized system. Each item that has any children in the emulated hierarchical system has an index entry in the index. The index entries in the index are linked together in a way that reflects the hierarchical relationship between the items associated with the index entries. Pathname resolution is performed by following direct links between the index entries associated with the items in a pathname, according to the sequence of the filenames within the pathname. By using an index whose index entries are linked in this manner, the process of accessing the items based on their pathnames is significantly accelerated, and the number of disk accesses performed during that process is significantly reduced.