EP0320266A2
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EP
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View composition in a data base management system
Assignee: HP Inc
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Filing: 1988-12-08
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Granted: —
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Expires: 2008-12-08
Abstract
Abstract In a database management system that operates according to the Structured Query Language standard, a query containing a reference to a view is processed by dynamically materializing the view through execution of the view definition. Once the view is materialized, it is treated as any other base table. To enable a query optimization plan to refer to the materialized view, a view node is introduced into the execution plan. The view node includes a subquery that results in the creation of the virtual table defined by the view. This created table is temporarily stored in a memory. The query optimizer can treat view nodes in the same manner as stored base tables, and thereby overcomes restrictions that were placed upon views by previous view decomposition approaches.
Inventors
- 👤 Ming-Chien Shan
- 👤 Peter Syngbaek
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 09:58
CPC Classifications
G; G06; G06F; G06F16/00; G06F16/20; G06F16/24; G06F16/245; G06F16/2453; G06F16/24534; G06F16/24539; G06F16/2455; G06F16/24552; G06F16/24553; G06F16/24561; G06F16/2458; G06F16/2477; Y; Y10; Y10S; Y10S707/00; Y10S707/99931; Y10S707/99932
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
124 words
A method for processing a query in a database system of the type in which data is stored in a memory in the form of base tables and in which a view is created by means of a definition of a virtual table stored in the memory which references one or more other tables, which query includes reference to at least one view, comprising the steps of: generating a query execution plan which includes a view node for at least one view referenced in the query; executing the definition of the view and temporarily storing the results of the execution in a buffer; and accessing the result temporarily stored in the buffer upon each reference to the view node in the query execution plan.
Claim 2
Independent Claim
124 words
A method for processing a query in a database system of the type in which data is stored in a memory in the form of base tables and in which a view is created by means of a definition of a virtual table stored in the memory which references one or more other tables, which query includes reference to at least one view, comprising the steps of: generating a query execution plan which includes a view node for at least one view referenced in the query; executing the definition of the view and temporarily storing the results of the execution in a buffer; and accessing the result temporarily stored in the buffer upon each reference to the view node in the query execution plan.
Claim 3
Dependent Claim
46 words
The method of claim 1 wherein the entire definition of the view is executed when the view node is first addressed in the query execution plan, and the entire virtual table defined by the view is temporarily stored in a memory upon completion of such execution.
Claim 4
Dependent Claim
42 words
The method of claim 1 or 2 wherein the definition of the view is executed individually for each tuple of the view as that tuple is requested in the execution of the query, and the tuple is temporarily stored in the buffer.
Claim 5
Dependent Claim
28 words
The method of claim 3 wherein each tuple stored in the buffer is replaced by a newly generated tuple upon a subsequent individual execution of the view definition.
Claim 6
Independent Claim
40 words
The method of any preceding claim wherein the base tables and the definition of a view are stored in a permanent memory, and the results of the execution of the definition of the view are stored in a non-permanent memory.
Claim 7
Dependent Claim
178 words
A method as claimed in claim 1 comprising the steps of: classifying each view referenced in the query as being one of (a) a single-table view which references only a single base table, (b) a complex view which contains at least one predetermined statement or operation, and (c) a simple view; generating a query execution plan which contains a node for each table and a node for at least each complex view referenced in the query; optimizing a query execution plan by (a) translating each definition of a single-table view into an equivalent query that references only base tables, (b) establishing a subquery for each complex view which, when executed, results in a materialization of the view and (c) determining whether to translate each simple view into an equivalent query or to establish a subquery to materialize the simple view; executing the query according to the optimized query execution plan and, for each view which is materialized during execution, temporarily storing the materialized view in a buffer; and retrieving the information which satisfies the condition of the query.
Claim 8
Dependent Claim
38 words
The method of claim 6 wherein a single determination of whether to translate the simple views into equivalent queries or to have materialization subqueries established for the simple views is made for all of the simple views together.
Claim 9
Dependent Claim
38 words
The method of claim 6 wherein the determination of whether each simple view is to be translated into an equivalent query or is to have a materialization subquery established for it is made for each simple view individually.
Claim 10
Dependent Claim
32 words
The method of claim 6 wherein the base tables and the definition of each view are stored in a permanent memory, and a materialized view is temporarily stored in a non-permanent memory.
Claim 11
Dependent Claim
86 words
In a database system of the type in which data is stored in a memory in the form of tables, a method for processing a query which includes at least one subquery, comprising the steps of: generating a query execution plan which includes a node for each subquery in the query; executing the subquery and temporarily storing the results of the execution in a memory; and accessing the result temporarily stored in the memory upon each reference to the subquery node in the query execution plan.
Claim 12
Dependent Claim
86 words
In a database system of the type in which data is stored in a memory in the form of tables, a method for processing a query which includes at least one subquery, comprising the steps of: generating a query execution plan which includes a node for each subquery in the query; executing the subquery and temporarily storing the results of the execution in a memory; and accessing the result temporarily stored in the memory upon each reference to the subquery node in the query execution plan.
Claim 13
Dependent Claim
40 words
The method of claim 10 wherein the entire subquery is executed when its node is first addressed in the query execution plan, and a table resulting from such execution is temporarily stored in the memory upon completion of such execution.
References Cited (Backward Citations)
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