Abstract: A method, system and apparatus for performing an inclusion hash join and an exclusion hash join using a hash join are provided. The inner and outer tables are transposed to left and right tables, respectively. A hash table is created from the left table, the right table is scanned, and the hash table is probed. If the right table hash value matches a hash table value, the actual values are compared. If they match, the current outer table row is included in the result. If an exclusion condition is present, the hash table is probed with the right-table-row's hash value. If no hash values match, the outer table row is added to the result and the next row is addressed. If one or more hash values match, the actual values are compared.

Abstract: A system, method and computer program for integrating a database and a data warehouse are disclosed. A request intended to be run on the database is received. If the request would benefit from a service provided by the data warehouse, data necessary to fulfill the request is transferred from the database to the data warehouse and the request is submitted to the data warehouse. Otherwise, the request is submitted to the database.

Abstract: A method, computer program, database system and data structure are disclosed for compressing a decimal type field in a database including one or more tables. Each of the one or more tables includes one or more rows. Each of the one or more rows includes an instance of the decimal type field. Space is allocated in one of P amounts to an instance of the decimal type field in a row, the amount being chosen based on the size of the value being stored in the instance of the decimal type field. One or more presence bits are set in the row to identify the amount of space allocated.

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 method, computer program, and database system are disclosed for executing database queries. The database includes a first table (T1) having a primary key (PK) column and a first correlated value column (CV1) and a second table (T2) having a foreign key (FK) column related to the primary key column of the first table and a second correlated value column (CV2). One implementation of the method includes preparing a database query for execution based at least in part on application of a derived constraint rule (DCR) having the form, (PK=FK)?CV2+C1?CV1?CV2+C2, where C1 and C2 are constants and “?” means “implies,” to produce an execution plan. Abort steps that are conditioned on changes in the DCR are also included in the execution plan. The plan is then executed.

Abstract: Implementations of a partitioned database system and a method of using a database system are disclosed. One system implementation includes storage facilities. Each storage facility includes data from database table rows. The database table rows in each storage facility that correspond to a specific database table are logically ordered according to a row identifier (row ID). The row ID includes a first value that is based on one or more columns of the table. The row ID also includes a second value that is based on one or more columns of the table, which may be different from or the same as those on which the first value is based. The first value of the row ID is predominate in determining the order of the rows in the storage facilities. The second value determines the order of those rows with identical first values.

Abstract: A method for performing a join of a first table and a second table is disclosed. In one instance, each of the plurality of first table rows is grouped into one of a plurality of first table partitions. It is determined that a partitioning column of the first table is specified in an equality condition of the join. One of the plurality of second table rows is selected, and a partition number is generated for the selected one of the plurality of second table rows. For a second table row for which a partition number was generated, a first table partition with a partition number that matches the generated partition number is identified, and a product join is used to join the one or more first table rows in the matching partition with the selected one of the second table rows.