Abstract: A query is received. It is determined that the query includes an inner join between a parent table and a child table. It is determined that the following relationships exist between the parent table and the child table: referential integrity (“RI”) between a primary key attribute (pk) in the parent table and a foreign key attribute (fk) in the child table, where “attribute” is defined to mean one or more columns; and a temporal relationship constraint (“TRC”) between a period attribute in the parent table and a TRC-attribute in the child table, the TRC-attribute being a date or time attribute. It is determined that the query does not access any attribute in the parent table other than the pk. It is determined that the query specifies an equality predicate of the form pk=fk. It is determined that the query specifies a condition that requires the TRC-attribute value to be contained in the parent table's period attribute duration.

Abstract: Trip data that includes points traversed during corresponding trips is received. Transportation network data that describes geographic locations and links between the geographic locations is received. The trip data and transportation network data are partitioned across a plurality of processing units executing on one or more processors. At each of the plurality of processing units, a subset of the trip data at the corresponding processing unit is locally matched to a subset of the transportation network data at the corresponding processing unit to identify a subset of paths of the transportation network data traversed by one or more of the trips.

Abstract: A database system is capable of processing a query and providing a progress indicator of the processing of the query based on at least a first cost factor. Initially, an estimate is set for the first cost factor. During processing of the query, the estimate of the first cost factor is updated to enable refinement of the progress indicator.

Abstract: A method, computer program, database system and data structure for indexing spatial objects are disclosed. Each spatial object has a location in an n-dimensional space. The indexing is for use in a partitioned parallel environment including P partitions. Each partition resides on one or more parallel processing systems. The n-dimensional space is divided into quad-tree cells (QTCs) in a quad-tree structure. Each spatial object is assigned to one or more QTCs based on the location of the spatial object in the n-dimensional space. A spatial object index entry is created which includes a designator for the QTC to which the spatial object is assigned and a pointer to the spatial object. The entries are sorted by their QTC numbers into a list. The list of entries is divided into P substantially equal parts. The entries associated with each part are stored in a different one of the P partitions.

Abstract: A method or apparatus for use with a database system that stores a join view associated with plural base relations includes receiving modification operations to modify at least two of the base relations of the join view, and re-ordering the received modification operations to avoid concurrent execution of modification operations of more than one of at least two base relations.

Abstract: A method and apparatus identifies SQL statements in a first transaction that specify modification operations that are commutative and associative. The SQL statements are combined into one SQL statement, and the one SQL statement is submitted to a database system. Optionally, or alternatively, multiple transactions can be grouped together into one transaction.

Abstract: A method and computer program for clustering a string are described. The string includes a plurality of characters. R unique n-grams T1 . . . R are identified in the string. For every unique n-gram TS, if the frequency of TS in a set of n-gram statistics is not greater than a first threshold, the string is associated with a cluster associated with TS. Otherwise, for every other n-gram TV in the string T1 . . . R, except S, if the frequency of n-gram TV is greater than the first threshold, and if the frequency of n-gram pair TS-TV is not greater than a second threshold, the string is associated with a cluster associated with the n-gram pair TS-TV. Otherwise, for every other n-gram TX in the string T1 . . . R, except S and V, the string is associated with a cluster associated with the n-gram triple TS-TV-TX. Otherwise, nothing is done.

Abstract: A database system includes a rescheduler that performs rescheduling of transactions in a scheduling queue based on one or more criteria. One criterion is whether a first transaction in the queue can be performed as a synchronized scan of a table with a second transaction that is currently executing. This enables the first and second transactions to share a segment of a buffer storage pool.

Abstract: A method and apparatus performs a partitioned joins of spatial objects in a database system. In one example arrangement, each spatial object is represented by z-cells in a z-ordered space. The z-cells of certain spatial objects are either duplicated or redistributed across multiple partitions in the database system to enable parallel joins of spatial objects.

Abstract: A database system receives a transaction that causes a tuple to be integrated into a join view. In response to receiving the transaction, a predefined first lock is placed on at least a portion of the join view, the predefined first lock conflicting with either a shared lock or an exclusive lock placed on the join view, but not conflicting with another predefined first lock placed on the join view. Also, a latch or semaphore associated with a value of a predetermined attribute of the tuple is obtained before integrating the tuple into the join view.

Abstract: A method, computer program and system for optimizing similarity string filtering are disclosed. A first data string comprising one or more data characters and selecting a second data string comprising one or more data characters are selected. At least one of a defined set of shapes is applied to the first data string to generate one or more patterns associated with the first data string. At least one of the defined set of shapes is applied to the second data string to generate one or more patterns associated with the second data string. The one or more patterns associated with the first data string are compared with the one or more patterns associated with the second data string to determine if one or more matching patterns exist. The first data string and the second data string are linked if one or more matching patterns exist.

Abstract: A database system is capable of performing interpolation (e.g., temporal interpolation) of data in response to receiving a database query. In one implementation, the database query contains an interpolation function. The database system in one example configuration is a parallel database system that has plural processing units that are capable of performing interpolation of data in parallel.

Abstract: A database system includes a locking mechanism for an aggregate materialized view defined on base relations. In response to updates of a base relation, predefined locks are placed on the aggregate materialized view. With locking mechanisms, transaction concurrency is enhanced by enabling concurrent updates of the materialized view by plural transactions in certain cases, while avoiding the situation in which multiple tuples belonging to the same group are integrated as separate tuples into the aggregate materialized view.

Abstract: A database system includes a locking mechanism for a view defined on one or more base relations. A B-tree index is defined on the view. In response to updates of a base relation, predefined locks are placed on the view. With locking mechanisms according to some embodiments of the invention, concurrency of transactions that access the view and B-tree index is enhanced by enabling concurrent updates of the materialized view by plural transactions in certain cases, while avoiding read-write and write-read conflicts.

Abstract: A database system includes a locking mechanism for a materialized view defined on base relations. In response to updates of a base relation, a name lock is placed on the materialized view. The name lock is a type of exclusive lock and is associated with a data structure containing a first parameter to identify a base relation of the materialized view being updated, and a second parameter to indicate a number of transactions updating the base relation. With locking mechanisms according to some embodiments of the invention, transaction concurrency is enhanced by enabling concurrent updates of a materialized view by plural transactions in certain cases.

Abstract: A database system includes a locking mechanism for a materialized view defined on base relations. In response to updates of a base relation, a predefined lock (e.g., Y lock or IY lock) is placed on the materialized view. With the locking mechanism, transaction concurrency is enhanced by enabling concurrent updates of a materialized view by plural transactions in certain cases.

Abstract: A database system includes a transaction rescheduling mechanism that reorders pending transactions based on whether one or more of the pending transactions conflict with any transactions that have been scheduled for execution. In one arrangement, the received pending transactions are stored in a first queue. The transactions that are scheduled for execution are stored in a second queue. The transactions are moved from the first queue to the second queue based on the reordering by the transaction rescheduling mechanism.

Abstract: A database system is able to represent spatial data with regions in a defined space, such as a z-ordered space. Instead of, or in addition to, a descending decomposition technique (e.g., a top-down decomposition technique) to represent the spatial data with the z-ordered space, the database system is able to use an ascending decomposition technique (e.g., a bottom-up decomposition technique).