Non-equijoin metadata
AssigneeTeradata US, Inc.
InventorsMichael Chaves, Kasturi Belur, Scott Shelton, Henry Fu
Life of this patent
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Abstract
The subject mater herein relates to database management and, more particularly, to non-equijoin metadata. Various embodiments described herein provide systems, methods, software, and data structures to facilitate non-equijoins of data. Some such embodiments include a data store to hold metadata describing relationships between database tables. The relationships between database tables may include one or more non-equijoins of tables in the form of one or more table-column pairs of a first table being non-equal to one or more table-column pairs of a second table. In some embodiments, the metadata may be used by a query generator to build query statements including one or more non-equijoin.
Claims10
A system comprising:
- a processor;
- a data storage device;
- a database, stored on the data storage device, to hold tables of data including columns and rows;
- the database including a first table, a second table, and metadata, the metadata including a description of a non-equijoin of the first table and the second table including a non-equijoin operator and a correspondence corresponding to a column of the first table and a column of the second table, the non-equijoin operator being at least one of a greater-than operator, a greater-than-or-equal-to operator, a less-than operator, or a less-than-or-equal-to operator;
- a query generator executed by the processor to:
- receive a data request from a requestor, the data request including a request for the column of the first table in view of the column of the second table for which a non-equijoin is described in the metadata;
- and
- build a query statement using the column of the first table, the column of the second table, and the non-equijoin operator as retrieved from the metadata in the database.
A method of providing non-equijoin data to a query generator, the method comprising:
- storing, in a database, a first table, a second table, and metadata, the metadata including a description of a non-equijoin of the first table and the second table including a non-equijoin operator and a correspondence corresponding to a column of the first table and a column of the second table, the non-equijoin operator being at least one a greater-than operator, a greater-than-or-equal-to operator, a less-than operator, or a less-than-or-equal-to operator;
- receiving a data request from a requestor including a request for making a join between the column of the first table and the column of the second table;
- retrieving the non-equijoin operator from the metadata in the database;
- and
- building a query statement using the column of the first table, the column of the second table, and the non-equijoin operator as retrieved from the database.
Dependencies are inferred from the claim text.