Abstract: Techniques are provided for moving data between partitions. Such a process may be performed without requiring any locks that block transactions that target a partition from being executed. Instead, such transactions may proceed while a move operation is being performed. The move operation involves copying data from the targeted partition to another partition that is hidden from (or “invisible” to) those transactions that attempt to read from or write to the partition. During the move operation, changes that are made to the partition are also reflected in a journal. Eventually, the changes reflected in the journal are drained and applied to the hidden partition. Once the partition and the hidden partition are synchronized, the identities of the partitions are swapped so that future transactions will target the previously-hidden partition instead of the previously-viewable partition.

Abstract: Techniques for creating and using partial indexes are provided. A partial index is an index that indexes one or more partitions of a partitioned table and does not index one or more other partitions of the partitioned table. Thus, if a partition of a partitioned table is rarely used, then an index may index all other partitions of the partitioned table or at least only those partitions that are written to or read from relatively frequently. Also, in preparation for loading data into a partition, indexing for the partition may be “turned off”, effectively making a full index a partial index. While the data is loaded into the partition, the partial index is still available for query processing. After the data is loaded into the partition, indexing for the partition is “turned on”, which causes the data in the partition to be indexed by the partial index.

Abstract: Techniques for processing “destructive” database statements are provided. Destructive database statements, when processed, cause metadata of a database object to be changed. Examples of such database statements include ones that delete an index, that set a column as unused, and that drop a constraint on a column. When such a statement is received, a change is made to metadata of a database object. Such a metadata change may involve setting an index as unusable, disabling a constraint, or invalidating a cursor. After the metadata change, a first time is determined. Then, it is determined when one or more database transactions that were pending at the first time have committed. After those database transaction(s) have committed, one or more operations are performed, such as dropping an index or dropping a constraint.

Abstract: Techniques for maintaining a global index in response to a partition being dropped are provided. In response to an instruction to drop a partition, partition identification data that identifies the partition is stored. Index entries, in the global index, that correspond to the dropped partition become “orphaned” entries. Later, an execution plan for a query is processed, where the execution plan targets a global index. During execution of the execution plan, one or more index entries are accessed. For each accessed index entry, the partition identification data is analyzed to determine if the index entry is an orphaned entry. If so, then the index entry is ignored for purposes of the query. Later, the global index may be updated to delete each orphaned entry. Such deletion may occur much later, such as during a time when the database is not queried or updated frequently.

Abstract: Systems, methods, and other embodiments associated with data sources adapted for parallel inference on triples associated with a semantic model are described. One example method includes creating a source table that is partitioned on triple predicate and stores triples for entailment. The source table may store compact triple identifiers that have been mapped to triple identifiers from the semantic model.

Abstract: The TABLE function mechanism available in a RDBMS is used to integrate RDF models into SQL queries. The table function invocation takes parameters including an RDF pattern, an RDF model, and an RDF rule base and returns result rows to the SQL query that contain RDF triples resulting from the application of the pattern to the triples of the model and the triples inferred by applying the rule base to the model. The RDBMS includes relational representations of the triples and the rules. Optimizations include indexes and materialized views of the representations of the triples, precomputed inferred triples, and a method associated with the TABLE function that rewrites the part of the SQL query that contains the TABLE function invocation as an equivalent SQL string. The latter technique is generally applicable to TABLE functions.

Abstract: Systems, methods, and other embodiments associated with equivalence reasoning are described. One example method includes iteratively inputting batches of unprocessed equivalence pairs from a semantic model to an operating memory. In the operating memory, one or more cliques for the input batches are built until no further batches remain. A clique designates a canonical representative resource for a group of equivalent resources as determined from the equivalence pairs. The one or more cliques are built for the input batches to a clique map in a remote access memory. The clique map is returned for use by the semantic model.

Abstract: Systems, methods, and other embodiments associated with equivalence reasoning are described. One example method includes constructing a clique map that maps groups of equivalent resources to a representative canonical resource. The clique map is constructed by iteratively inputting batches of equivalence pairs from a semantic model to operating memory and building, in operating memory, one or more cliques for the input batch. Cliques for various input batches of equivalence pairs are merged in memory to produce the clique map for use by the semantic model. Triples associated with the semantic model may be consolidated by replacing resources that are in a clique with their corresponding representative canonical resource.

Abstract: Systems, methods, and other embodiments associated with data sources adapted for parallel inference on triples associated with a semantic model are described. One example method includes creating a source table that stores triples for entailment in a manner that is adapted for parallel inference. The source table may be partitioned by triple predicate or may store compact triple identifiers that have been mapped to triple identifiers from the semantic model.

Abstract: An un-indexed, partitioned temporary table and an exchange table are used in the inferencing of semantic data in a relational database system. The exchange table has the same structure as a semantic data table storing the semantic data. In the inferencing process, a new partition is created in the semantic data table. Inference rules are executed on the semantic data table, and any newly inferred semantic data generated is added to the temporary table. Once no new data is generated, the inferred semantic data is copied from the temporary table into the exchange table. Indexes that are the same as indexes for the semantic data table are built for the exchange table. The indexed data in the exchange table is then exchanged into the new partition in the semantic data table. By use of the un-indexed, partitioned temporary table, incremental maintenance of indexes is avoided, thus allowing for greater efficiency.

Abstract: Techniques for using arbitrary sets of objects to constrain objects in database systems. The constraint set of objects is associated with the constrained object in the database system and the database system will perform an operation which adds an object to the constrained object only if the object being added belongs to the constraint set. In a preferred embodiment, the techniques are employed to obtain constraint sets of terms from ontologies which are then used to constrain columns containing those terms. An implementation of the techniques makes a materialized view out of the objects in the constraint set and uses the materialized view to define a referential integrity constraint on the constrained column.

Abstract: Systems, methods, and other embodiments associated with data sources adapted for parallel inference on triples associated with a semantic model are described. One example method includes creating a source table that stores triples for entailment in a manner that is adapted for parallel inference. The source table may be partitioned by triple predicate or may store compact triple identifiers that have been mapped to triple identifiers from the semantic model.

Abstract: Systems, methods, and other embodiments associated with equivalence reasoning are described. One example method includes constructing a clique map that maps groups of equivalent resources to a representative canonical resource. The clique map is constructed by iteratively inputting batches of equivalence pairs from a semantic model to operating memory and building, in operating memory, one or more cliques for the input batch. Cliques for various input batches of equivalence pairs are merged in memory to produce the clique map for use by the semantic model. Triples associated with the semantic model may be consolidated by replacing resources that are in a clique with their corresponding representative canonical resource.

Abstract: Systems, methodologies, media, and other embodiments associated with supporting reference partitioned tables in a relational database are described. One example method includes identifying a partitioning strategy (e.g., range, list, hash) associated with a parent table that is related to a child table by a referential constraint. The example method may also include creating the child table to be a reference-partitioned table partitioned according to the partitioning strategy associated with the parent table. The example method may also include creating the child table to be equi-partitioned with respect to the parent table. The child table is not to replicate a partition key of the parent table but rather is to inherit a partitioning key associated with the parent table through a foreign key relationship.

Abstract: The TABLE function mechanism available in a RDBMS is used to integrate RDF models into SQL queries. The table function invocation takes parameters including an RDF pattern, an RDF model, and an RDF rule base and returns result rows to the SQL query that contain RDF triples resulting from the application of the pattern to the triples of the model and the triples inferred by applying the rule base to the model. The RDBMS includes relational representations of the triples and the rules. Optimizations include indexes and materialized views of the representations of the triples, precomputed inferred triples, and a method associated with the TABLE function that rewrites the part of the SQL query that contains the TABLE function invocation as an equivalent SQL string. The latter technique is generally applicable to TABLE functions.

Abstract: An un-indexed, partitioned temporary table and an exchange table are used in the inferencing of semantic data in a relational database system. The exchange table has the same structure as a semantic data table storing the semantic data. In the inferencing process, a new partition is created in the semantic data table. Inference rules are executed on the semantic data table, and any newly inferred semantic data generated is added to the temporary table. Once no new data is generated, the inferred semantic data is copied from the temporary table into the exchange table. Indexes that are the same as indexes for the semantic data table are built for the exchange table. The indexed data in the exchange table is then exchanged into the new partition in the semantic data table. By use of the un-indexed, partitioned temporary table, incremental maintenance of indexes is avoided, thus allowing for greater efficiency.

Abstract: Systems, methodologies, media, and other embodiments associated with supporting reference partitioned tables in a relational database are described. One example method includes identifying a partitioning strategy (e.g., range, list, hash) associated with a parent table that is related to a child table by a referential constraint. The example method may also include creating the child table to be a reference-partitioned table partitioned according to the partitioning strategy associated with the parent table. The example method may also include creating the child table to be equi-partitioned with respect to the parent table. The child table is not to replicate a partition key of the parent table but rather is to inherit a partitioning key associated with the parent table through a foreign key relationship.

Abstract: The method for processing data in a relational database wherein ontology data that specifies terms and relationships between pairs of said terms expressed in an OWL document is stored in the database, database queries that include a semantic matching operator are formed which identify the ontology data and further specify a stated relationship between two input terms, and the query is executed to invoke the semantic matching operator to determine if the two input terms are related by the stated relationship by consulting said ontology data.

Abstract: A system for enabling a user of a relational database to define and enforce ordered check constraints to insure that defined logical relationships are maintained between data values in pairs of adjacent rows when adjacency is defined by some ordering of the data. These inter-row conditions, here called “ordered check constraints,” are expressed by a logical expressions which define a required relationship between the attributes of a given row and its adjacent row or rows. Arbitrarily complex expressions involving these sets of attributes can be formed to model the constraints of interest. These expressions can be created by the database in support of, for example, traditional primary key or uniqueness constraints, or they can be provided by the database user to model new more complex constraints such as a requirement that there be no gaps in a list of serial numbers.

Abstract: Techniques for using arbitrary sets of objects to constrain objects in database systems. The constraint set of objects is associated with the constrained object in the database system and the database system will perform an operation which adds an object to the constrained object only if the object being added belongs to the constraint set. In a preferred embodiment, the techniques are employed to obtain constraint sets of terms from ontologies which are then used to constrain columns containing those terms. An implementation of the techniques makes a materialized view out of the objects in the constraint set and uses the materialized view to define a referential integrity constraint on the constrained column.