Abstract: An extender for a computer-implemented relational database system is disclosed for storing, querying, and retrieving structured documents. The extender provides a new abstract data type and includes a plurality of user defined functions for storing, querying, and retrieving structured documents internally, as character-based large objects (CLOB), or externally, in flat files or URLs, for example. A method and apparatus using an extender having a “conditional select” functionality is further disclosed for querying structured documents. The “conditional select” functionality is based on user defined functions residing within the extender being applied to a projection in a structured query in the database system. A method and apparatus using an extender having a set of user defined functions is further disclosed for creating one or more indexes for structured documents stored in the relational database system.

Abstract: An extender for a computer-implemented relational database system is disclosed for storing, querying, and retrieving structured documents. The extender provides a new abstract data type and includes a plurality of user defined functions for storing, querying, and retrieving structured documents internally, as character-based large objects (CLOB), or externally, in flat files or URLs, for example. A method and apparatus using an extender having a “conditional select” functionality is further disclosed for querying structured documents. The “conditional select” functionality is based on user defined functions residing within the extender being applied to a projection in a structured query in the database system. A method and apparatus using an extender having a set of user defined functions is further disclosed for creating one or more indexes for structured documents stored in the relational database system.

Abstract: A method and apparatus using an extender for a computer-implemented relational database system is disclosed for storing, querying, and retrieving structured documents. The extender provides a new abstract data type and includes a plurality of user defined functions for storing, querying, and retrieving structured documents internally, as character-based large objects (CLOB), or externally, in flat files or URLs, for example. The extender has “conditional select” functionality, “conditional select” functionality is based on user defined functions residing within the extender being applied to a projection in a structured query in the database system. The extender also has a set of user defined functions for creating one or more indexes for structured documents stored in the relational database system using already created B+ tree index structures implemented in the database system to support the indexes.

Abstract: An extender for a computer-implemented relational database system is disclosed for storing, querying, and retrieving structured documents. The extender provides a new abstract data type and includes a plurality of user defined functions for storing, querying, and retrieving structured documents internally, as character-based large objects (CLOB), or externally, in flat files or URLs, for example. A method and apparatus using an extender having a “conditional select” functionality is further disclosed for querying structured documents. The “conditional select” functionality is based on user defined functions residing within the extender being applied to a projection in a structured query in the database system. A method and apparatus using an extender having a set of user defined functions is further disclosed for creating one or more indexes for structured documents stored in the relational database system.

Abstract: A method, apparatus, and article of manufacture for a computer-implemented live connection manager. A statement is executed in a computer to retrieve data from a database stored on a data storage device connected to the computer. In particular, a first statement is received from another computer via an internet network. The first statement is prepared to create an executable structure for executing the first statement. A second statement is received from another computer via an internet network. Then, when the received second statement or portion thereof is the same as the first statement or portion thereof, processing the second statement or portion thereof by executing the executable structure created for the first statement or portion thereof.

Abstract: Method for specifying SQL "full outer joins" which enables the use of arbitrary join conditions in specifying the query. This is enabled by equating a full outer join with a left outer join unioned with a right outer join less the matched tuples from the right outer join. A number of embodiments further present improvements in execution speed. One such improvement utilizes as a second operand of the union query a novel operator, the "ANTI-JOIN". The anti-join is implemented as a right outer join coupled with an ISNULL predicate.

Abstract: A method, apparatus, and article of manufacture for replicating data stored in source database tables in a database management system implemented by a server at a remote client implemented on a client computer. The method comprises the steps of receiving a subscription message from the client computer, wherein the subscription message specifies a remote client database table and a data replication period, receiving a change log from the database management system at the data replication agent, generating a table of changed data by using the change log, data replication period, and source database table to reconstruct changes to the remote client database table, and transmitting the changed data table to the remote client.

Abstract: A method, apparatus, and article of manufacture for providing access to information stored in a database management system. The method and apparatus uses an intelligent generic query agent to operate with a wide variety of remote users, and to allow implementation of a wide variety of optimization schemes. The method comprises receiving a request from the remote user at the agent, transforming the request into database management system commands optimized in accordance with user-specified optimization criteria, transmitting the database management system commands to the database management system, receiving the database management system command result from the database management system in the agent, transforming the database management system command result into a response message, and transmitting the response message to from the agent to the remote user.

Abstract: A computer database system utilizes a method for performing a right outer join of database tables without sorting the inner table (T.sub.2). The processing of each tuple in the outer table (T.sub.1) includes the preservation in the joint output of all tuples in T.sub.2 which are in its responsibility region. The initialization step of the process preserves in the join output all of the tuples in T.sub.2 which have column set values less than the lowest column set value in T.sub.1, i.e. the first tuple in T.sub.1, since T.sub.1 is sorted or accessed using a sorted index. The responsibility region for tuples in T.sub.1, other than the last tuple, is defined as those tuples which have column set values less than the column set value for the next tuple in T.sub.1 and greater than or equal to the column set value for the current T.sub.1 tuple. The last tuple in T.sub.1 must preserve all of the tuples in T.sub.2 which have not already been preserved in T.sub.2, i.e.

Abstract: A computer database system utilizes a method for performing a right outer join of database tables without sorting the inner table (T.sub.2). The processing of each tuple in the outer table (T.sub.1) includes the preservation in the joint output of all tuples in T.sub.2 which are in its responsibility region. The initialization step of the process preserves in the join output all of the tuples in T.sub.2 which have column set values less than the lowest column set value in T.sub.1, i.e. the first tuple in T.sub.1, since T.sub.1 is sorted or accessed using a sorted index. The responsibility region for tuples in T.sub.1, other than the last tuple, is defined as those tuples which have column set values less than the column set value for the next tuple in T.sub.1 and greater than or equal to the column set value for the current T.sub.1 tuple. The last tuple in T.sub.1 must preserve all of the tuples in T.sub.2 which have not already been preserved in T.sub.2, i.e.

Abstract: Results of a relational data base management system are joined in a process requiring, first, existence of an index on the join columns of the inner table, and, second, ordering on the join column of the first table. First, the index on the inner table's join column is scanned for rows of the inner table having join column values matching such values of rows in the outer table. This is done in a single pass through the outer table. Next, a temporary work table containing the identifiers of inner table rows having join column values matching those of the outer table is produced by concatenating the row identifiers to their matching outer table rows. Following this, the temporary work table is ordered by the identifiers. Last, the identifier list of inner table rows is used to retrieve the corresponding rows of the inner table.

Abstract: This invention measures the degree of clustering of an index for a relational data base table, estimates the number of physical page accesses required to access the table using a partial index scan using the index, and selects the index providing the fastest access path to the table. The degree of clustering is measured as follows:DC=Number of clustered rows (NCR)/Total rows (NR)A multiplier greater than 1 can be applied to the degree of clustering to reflect the benefit of having consecutively accessed rows on adjacent or nearby data pages.The degree of clustering so calculated is used to estimate the number of random and sequential page accesses required for a partial index scan. These numbers of accesses are then multiplied by the unit time required for each, and added to the total CPU processing time required to arrive at the estimated total time for the scan.

Abstract: A two-pass method for relocating a set of linked control blocks stored away on a persistent medium after a first pass and then rewritten into internal memory of a computing facility during second and subsequent passes each time an application to which the control blocks are bound is executed. The first pass involves path following and coloring pointers affected by the relocation, mapping discontiguously located blocks into a linear address space, changing affected control blocks to location offsets, and writing out the linked control blocks to DASD store. Upon the second pass, virtual addresses are substituted for the offsets upon rewriting of the control blocks to internal memory.