Abstract: In a database system, a method for optimization of a query is described. When a query is received which requests data from a database, a plurality of plans which can be used for obtaining data requested by the query are enumerated. A search tree is created based upon these plans, with nodes of the search tree representing segments of the plans. A limited number of nodes of the search tree are selected for evaluation to limit the effort spent on query optimization. A complete plan for execution of the query is generated by evaluating the selected nodes of the search tree and, if the evaluation determines that a given node is more favorable than comparable nodes previously evaluated, retaining the given node as part of the complete plan.

Abstract: A system and methodology for extraction and aggregation of data from dynamic content is described. In one embodiment, for example, a method is described for extracting and structuring items of data from content available via the Internet, the method comprises steps of: receiving input of a user specifying at least one source of content available via the Internet, types of data to be extracted from the at least one source, and fields for structuring extracted items of data; retrieving content from the at least one source; parsing the retrieved content to extract items of data of the types specified by the user; and mapping the extracted items of data to the fields specified by the user so as to transform the extracted items of data into a structured format.

Abstract: A database system providing methods for eager and opportunistic property enforcement is described. Plan fragments are generated for obtaining data requested by a query. Plan fragments are grouped together in classes based upon tables of the database covered by each plan fragment. For each class, a particular plan fragment having the lowest execution costs for obtaining the data requested by the query is determined. If grouping is not required at a given class, an operator enforcing ordering is added to this particular sub-plan. However, if grouping is required at the given class, an operator enforcing both grouping and ordering is added to this sub-plan.

Abstract: A system providing methods enabling data in Extensible Markup Language (“XML”) format to be extracted, transformed and stored in a database, file system or main memory is described. The extraction and transformation process is generalized and can be used on various types of XML data, enabling XML data to be stored and queried using standard database query methodologies. The system includes parse-time functionality to transform XML documents into a structure having an interface that enables efficient access to the underlying data. The system also includes query execution-time functionality providing greater efficiency by bringing only the relevant portions of transformed XML data into memory in response to a query. The system parses and translates queries into a structure that can be executed without the need to write custom application-specific navigation code to search XML data. The system also enables original XML documents (or portions thereof) to be recomposed when required.

Abstract: A system with methodology for performing relational operations over relational data and data retrieved from Simple Object Access Protocol (SOAP) operations is described. In one embodiment, a method of the present invention is described for performing database operations on data obtained from a web service, the method comprises steps of: creating at least one proxy table in a database, each proxy table mapping to a method of the web service; in response to a database operation on a particular proxy table, converting the database operation into a format for invoking a particular method of the web service based upon the corresponding mapping; invoking the particular method of the web service; converting results obtained from invoking the particular method into data for use at the database based upon the corresponding mapping; and performing the database operation on the data at the database.

Abstract: A Client/Server Database System with improved methods for providing access to highly-concurrent data, such as of B-Tree data structures, is described. When the system receives a request to insert a key value into a B-Tree at page that does not have sufficient room, the system must split at the tree at the leaf level. This is done by allocating a new page, and moving some of the key values from the old page to the new page. The split itself propagates upward. To do the split itself, the system obtains address locks for the two pages, and marks both as undergoing “split” (i.e., a split operation)—the system sets a Boolean flag or “split bit” to “true.” When the split is propagated up, a “side entry” is added to the old page to point to the newly allocated page. The old page, however, may not have sufficient room for storing this new entry (e.g., when it is already full). Accordingly in such a case, the parent page must split also.

Abstract: A system providing improved methods for data replication is described. A method for replicating a transaction from a primary database to a replicate database while the replicate database remains available for use comprises: recording information about a transaction being performed at a primary database in a transaction log; synchronously copying the information about the transaction in the transaction log to a mirrored transaction log; generating a reconstructed transaction based on the information about the transaction copied to the mirrored transaction log; and applying the reconstructed transaction at the replicate database while the replicate database remains available for use.

Abstract: Systems and methods for collecting information distributed over a computer network are described. Problems addressed by the invention include the marking of content distributed over a network, the instant display of current information distributed over a network, and the retrieval of information at a browser without an intermediary step to save the information. The invention enables customized aggregation of content distributed over a network in real-time. The invention includes a recursive scripting language. Scripts in the recursive scripting language may be used to point dynamically to web objects whose URLs have changed. Embodiments include a feature extraction object used for identifying similar information objects. Feature Extraction may use ‘fuzzy logic’ to insure that targeted content is identified despite modifications in the source page.

Abstract: A database system providing improved methods for asynchronous logging of transactions is described. Log records are created describing changes to a database made by a transaction. When a command committing changes to the database for the transaction is received, a logging request is placed in a queue. An asynchronous logging service removes requests from the queue and transfers log records from the transaction to a shared cache. The shared cache stores log records before they are written to the transaction log. The logging service writes log pages containing log records for the transaction from the cache to the transaction log. After all log pages in the cache for the transaction have been written to the transaction log, changes to the database made by the transaction can be committed to the database.

Abstract: A Database Development System is described that provides methodologies for creating an HTML or Web database control object (the “HTML DataWindow”) for use in a Client/Server Database System The HTML DataWindow serves as a thin-client DataWindow implementation for Web applications that provides most of the data manipulation, presentation, and scripting capabilities of the PowerBuilder DataWindow, without requiring any runtime DLLs (e.g., PowerBuilder runtime dynamic link libraries) on the client. DataWindow validation rules, formatting, and edit styles are automatically converted by the system into equivalent HTML and JavaScript, without coding by the user. HTML is generated that is suitable for the target browser. A plurality of functions and events are implemented by the generation of JavaScript which is downloaded to the client. In this manner, the Web or HTML DataWindow Design-Time Dontrol supports generation of a runtime DataWindow object in HTML.

Abstract: An improved method for creating an index based on a path-compressed binary trie in a database system comprising database tables and indexes on those tables is described. For a given index to be created, a path-compressed binary trie for the given index is determined. The path-compressed binary trie comprises internal nodes and leaf nodes. Based on a traversal of the path-compressed binary trie, an index is created comprising a first array of internal nodes encountered during the traversal, and a second array of leaf nodes encountered during the traversal. The database system employs said first and second arrays for providing index-based access for a given key value.

Abstract: In a database system, a method for optimization of a query is described. When a query is received which requests data from a database, a plurality of plans which can be used for obtaining data requested by the query are enumerated. A search tree is created based upon these plans, with nodes of the search tree representing segments of the plans. A limited number of nodes of the search tree are selected for evaluation to limit the effort spent on query optimization. A complete plan for execution of the query is generated by evaluating the selected nodes of the search tree and, if the evaluation determines that a given node is more favorable than comparable nodes previously evaluated, retaining the given node as part of the complete plan.

Abstract: A database system providing improved methods for optimization and execution of queries aggregating information from multiple database tables is described. The improved method breaks serial operations into a group of child operations that can be individually optimized and processed in parallel. A query including a grouping operator over a union node is split by pushing the grouping operation down into each input arm of the union node. Specifically, grouping operators are inserted into each child arm of qualifying union nodes, enabling separate physical database tables to be summarized in parallel. Each of the child grouping operators concurrently groups data and generates summary results in parallel, taking advantage of capabilities of available parallel processing hardware. The aggregate operators of the original master grouping operator are modified to accept and correctly synthesize sub-aggregated results generated by each of the child grouping operators.

Abstract: A database system providing improved methods for asynchronous logging of transactions is described. Log records are created describing changes to a database made by a transaction. When a command committing changes to the database for the transaction is received, a logging request is placed in a queue. An asynchronous logging service removes requests from the queue and transfers log records from the transaction to a shared cache. The shared cache stores log records before they are written to the transaction log. The logging service writes log pages containing log records for the transaction from the cache to the transaction log. After all log pages in the cache for the transaction have been written to the transaction log, changes to the database made by the transaction can be committed to the database.

Abstract: A system and methodology for generating bushy trees using a left-deep tree join enumeration strategy for optimizing execution of a database query is described. In response to receipt of a query specifying at least one join condition between two or more database tables, each query block comprising an atomic portion of the query is identified and subplans are created for each query block based on grouping portions of each query block. At least one favorable access plan is determined for each subplan of each query block based, at least in part, on estimated execution costs. An optimal access plan for each query block is generated based upon at least one favorable access plan determined for each subplan. A query execution plan is then constructed based upon the optimal access plan generated for each query block.

Abstract: An improved normalization methodology enabling better optimization of SQL queries is described. The normalization methodology effectively handles three-valued SQL search conditions and operates in reduced memory environments. A query is examined and selectively normalized by examining each segment of the query to determine whether it is advantageous to fully convert that segment to conjunctive normal form (CNF). If full conversion of the segment to CNF is not advantageous, then only the useful conjunctive conditions (prime implicates) that can be derived from the original input are saved. These useful conjuncts (prime implicates) are unioned with the original statement, resulting in a search condition that is semantically equivalent to the original expression, but that can be better exploited by a query optimizer. This enables better optimization of the original query without the system overhead that would result from full normalization of the query.

Abstract: An improved method for creating an index based on a path-compressed binary trie in a database system comprising database tables and indexes on those tables is described. For a given index to be created, a path-compressed binary trie for the given index is determined. The path-compressed binary trie comprises internal nodes and leaf nodes. Based on a traversal of the path-compressed binary trie, an index is created comprising a first array of internal nodes encountered during the traversal, and a second array of leaf nodes encountered during the traversal. The database system employs said first and second arrays for providing index-based access for a given key value.

Abstract: A database system is described that provides a methodology for significantly reducing latching costs associated with index pages in non-covered index scans, all without the need for using a conventional “shadow page.” The database system uses a “look ahead” list (LA) to save up to a preset number (e.g., 60) of ROWIDs (row identifiers) from the qualifying index keys. Since a ROWID is typically small (e.g., about 6 bytes), the space needed to store 60 ROWIDs is typically much smaller than the underlying page size (which typically range from 2K to 32K in systems). Thus, instead of finding just one next qualifying key as is conventionally done, up to a selected number (e.g., 60) of qualifying keys on the current page are found and the ROWIDs from them are stored in the look ahead list. In many cases, the copying costs are eliminated too.

Abstract: An improved method for handling database queries including functional expressions against columns having enumerated storage is described. Upon receipt of a query including a predicate having at least one functional expression referencing at least one database column containing offsets to values in enumerated storage, a look-up table is created for storing results of evaluation of the predicate against the values in enumerated storage. Each functional expression of the predicate is evaluated against the values in enumerated storage and the results of evaluation are stored in the look-up table. Results stored in the look-up table may then be accessed through use of the offsets to values in enumerated storage. The method may also be utilized for projecting expressions against database columns having enumerated storage.

Abstract: A database system providing methods for eager and opportunistic property enforcement is described. Plan fragments are generated for obtaining data requested by a query. Plan fragments are grouped together in classes based upon tables of the database covered by each plan fragment. For each class, a particular plan fragment having the lowest execution costs for obtaining the data requested by the query is determined. If grouping is not required at a given class, an operator enforcing ordering is added to this particular sub-plan. However, if grouping is required at the given class, an operator enforcing both grouping and ordering is added to this sub-plan.