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US5713015A
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Reordering of complex SQL queries involving GROUPBYs, joins, outer joins and full outer joins
Assignee: International Business Machines Corp
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Filing: 1996-05-30
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Granted: 1998-01-27
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Expires: 2016-05-30
Abstract
Abstract A method, apparatus, and article of manufacture for query simplification by applying generalized inference propagation and generalized transitive closure in SQL queries having selection, projection, join, outer join, and intersection operations. The disclosed transformations and enumeration method unify and solve the problems of 1) unnesting join aggregate queries, and 2) complete enumeration of queries containing outer joins, when the outer join predicate references an aggregated value, or the predicate references more than two base relations in a query subtree. The system first eliminates redundant sub-expressions and modifies expensive binary operations to inexpensive binary operations, then converts complex predicates to simple predicates by application of a generalized selection (GS) operator.
Inventors
- 👤 Piyush Goel
- 👤 Balakrishna Raghavendra Iyer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:40
CPC Classifications
G; G06; G06F; G06F16/00; G06F16/20; G06F16/24; G06F16/245; G06F16/2453; G06F16/24534; G06F16/24537; G06F16/24547; Y; Y10; Y10S; Y10S707/00; Y10S707/99931; Y10S707/99932; Y10S707/99933; Y10S707/99934
Claims Analysis
Total Claims: 54
Claim 1
Independent Claim
113 words
A method of simplifying an SQL query in a computer having a memory, the SQL query being performed by the computer to retrieve data from a relational database stored in a electronic storage device coupled to the computer, the method comprising the steps of: (a) iteratively eliminating, in the memory of the computer, redundant sub-expressions from the SQL query and modifying expensive binary operations in the SQL query to inexpensive binary operations, so that only simple and complex predicates remain in the SQL query; and (b) iteratively converting, in the memory of the computer, the complex predicates remaining in the SQL query to simple predicates by application of a generalized selection (GS) operator.
Claim 2
Independent Claim
113 words
A method of simplifying an SQL query in a computer having a memory, the SQL query being performed by the computer to retrieve data from a relational database stored in a electronic storage device coupled to the computer, the method comprising the steps of: (a) iteratively eliminating, in the memory of the computer, redundant sub-expressions from the SQL query and modifying expensive binary operations in the SQL query to inexpensive binary operations, so that only simple and complex predicates remain in the SQL query; and (b) iteratively converting, in the memory of the computer, the complex predicates remaining in the SQL query to simple predicates by application of a generalized selection (GS) operator.
Claim 3
Dependent Claim
30 words
The method of claim 1 further comprising the step of iteratively applying, in the memory of the computer, a simplification identity to a SELECT DISTINCT operator in the SQL query.
Claim 4
Dependent Claim
32 words
The method of claim 1 further comprising the step of iteratively applying, in the memory of the computer, a simplification identity for a push-up of a GROUPBY operator in the SQL query.
Claim 5
Dependent Claim
133 words
The method of claim 1 wherein the GS operator, σ p * r 2 ,r 3 ! (r 1 ), of relation r 1 with respect to relations r 2 and r 3 comprises the relation <R 1 , V 1 , E>, wherein: E'=σ.sub.p (r.sub.1){π.sub.R.sbsb.2.sup.c.sub.V.sbsb.2 (r.sub.1)-π.sub.R.sbsb.2.sup.c.sub.V.sbsb.2 (σ.sub.p (r.sub.1))}{π.sub.R.sbsb.3.sup.c.sub.V.sbsb.3 (r.sub.1)-π.sub.R.sbsb.3.sup.c.sub.V.sbsb.3 (σ.sub.p (r.sub.1))} and wherein r 1 =<R 1 , V 1 ,E 1 >, r 2 =<R 2 ,V 2 ,E 2 >, and r 3 =<R 3 ,V 3 ,E 3 > comprise three relations such that R 2 .OR right.R 1 , R 3 .OR right.R 1 , R 2 ∩R 3 =φ, V 2 .OR right.V 1 , V 3 .OR right.V 1 , and V 2 ∩V 3 =φ, and p denotes a null-intolerant predicate in R 1 .
Claim 6
Dependent Claim
58 words
The method as set forth in claim 1 above, wherein the iteratively converting step comprises the step of applying a simplification expression to the SQL query comprising: ##EQU22## wherein X i =<R i ,V i ,E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 7
Dependent Claim
60 words
The method as set forth in claim 1 above, wherein the iteratively converting step comprises the step of applying a simplification expression to the SQL query comprising: ##EQU23## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 8
Dependent Claim
60 words
The method as set forth in claim 1 above, wherein the iteratively converting step comprises the step of applying a simplification expression to the SQL query comprising: ##EQU24## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 9
Dependent Claim
60 words
The method as set forth in claim 1 above, wherein the iteratively converting step comprises the step of applying a simplification expression to the SQL query comprising: ##EQU25## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 10
Dependent Claim
60 words
The method as set forth in claim 1 above, wherein the iteratively converting step comprises the step of applying a simplification expression to the SQL query comprising: ##EQU26## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 11
Dependent Claim
60 words
The method as set forth in claim 1 above, wherein the iteratively converting step comprises the step of applying a simplification expression to the SQL query comprising: ##EQU27## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 12
Dependent Claim
60 words
The method as set forth in claim 1 above, wherein the iteratively converting step comprises the step of applying a simplification expression to the SQL query comprising: ##EQU28## wherein X i =<R i , V i , V i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 13
Dependent Claim
60 words
The method as set forth in claim 1 above, wherein the iteratively converting step comprises the step of applying a simplification expression to the SQL query comprising: ##EQU29## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 14
Dependent Claim
60 words
The method as set forth in claim 1 above, wherein the iteratively converting step comprises the step of applying a simplification expression to the SQL query comprising: ##EQU30## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 15
Dependent Claim
60 words
The method as set forth in claim 1 above, wherein the iteratively converting step comprises the step of applying a simplification expression to the SQL query comprising: ##EQU31## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 16
Dependent Claim
60 words
The method as set forth in claim 1 above, wherein the iteratively converting step comprises the step of applying a simplification expression to the SQL query comprising: ##EQU32## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 17
Dependent Claim
60 words
The method as set forth in claim 1 above, wherein the iteratively converting step comprises the step of applying a simplification expression to the SQL query comprising: ##EQU33## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 18
Dependent Claim
60 words
The method as set forth in claim 1 above, wherein the iteratively converting step comprises the step of applying a simplification expression to the SQL query comprising: ##EQU34## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 19
Independent Claim
133 words
An apparatus for simplifying an SQL query, comprising: (a) a computer having a memory and an electronic storage device coupled thereto, the data storage device storing a relational database; (b) means, performed by the computer, for accepting the SQL query into the memory of the computer, the SQL query being executed by the computer to retrieve data from a relational database stored in the computer; (c) means, performed by the computer, for iteratively eliminating redundant sub-expressions in the SQL query and modifying expensive binary operations in the SQL query to inexpensive binary operations, so that only simple and complex predicates remain in the SQL query; and (d) means, performed by the computer, for iteratively converting the complex predicates in the SQL query to simple predicates by application of a generalized selection (GS) operator.
Claim 20
Independent Claim
133 words
An apparatus for simplifying an SQL query, comprising: (a) a computer having a memory and an electronic storage device coupled thereto, the data storage device storing a relational database; (b) means, performed by the computer, for accepting the SQL query into the memory of the computer, the SQL query being executed by the computer to retrieve data from a relational database stored in the computer; (c) means, performed by the computer, for iteratively eliminating redundant sub-expressions in the SQL query and modifying expensive binary operations in the SQL query to inexpensive binary operations, so that only simple and complex predicates remain in the SQL query; and (d) means, performed by the computer, for iteratively converting the complex predicates in the SQL query to simple predicates by application of a generalized selection (GS) operator.
Claim 21
Dependent Claim
131 words
A program storage device readable by a computer, tangibly embodying a program of instructions executable by the computer to perform method steps for simplifying an SQL query in a computer having a memory, the SQL query being performed by the computer to retrieve data from a relational database stored in an electronic storage device coupled to the computer, the method comprising the steps of: (a) iteratively eliminating, in the memory of the computer, redundant sub-expressions in the SQL query and modifying expensive binary operations in the SQL query to inexpensive binary operations, so that only simple and complex predicates remain in the SQL query; and (b) iteratively converting, in the memory of the computer, the complex predicates in the SQL query to simple predicates by application of a generalized selection operator.
Claim 22
Dependent Claim
131 words
A program storage device readable by a computer, tangibly embodying a program of instructions executable by the computer to perform method steps for simplifying an SQL query in a computer having a memory, the SQL query being performed by the computer to retrieve data from a relational database stored in an electronic storage device coupled to the computer, the method comprising the steps of: (a) iteratively eliminating, in the memory of the computer, redundant sub-expressions in the SQL query and modifying expensive binary operations in the SQL query to inexpensive binary operations, so that only simple and complex predicates remain in the SQL query; and (b) iteratively converting, in the memory of the computer, the complex predicates in the SQL query to simple predicates by application of a generalized selection operator.
Claim 23
Dependent Claim
29 words
The apparatus of claim 18 further comprising means for iteratively applying, in the memory of the computer, a simplification identity to a SELECT DISTINCT operator in the SQL query.
Claim 24
Dependent Claim
31 words
The apparatus of claim 18 further comprising means for iteratively applying, in the memory of the computer, a simplification identity for a push-up of a GROUPBY operator in the SQL query.
Claim 25
Dependent Claim
137 words
The apparatus of claim 18 wherein the GS operator, σ p * r 2 ,r 3 !(r 1 ), of relation r 1 with respect to relations r 2 and r 3 comprises the relation <R 1 , V 1 , E'>, wherein: E'=σ.sub.p (r.sub.1){π.sub.R.sbsb.2.sup.c.sub.v.sbsb.2 (r.sub.1)-π.sub.R.sbsb.2.sup.c.sub.v.sbsb.2 (σ.sub.p (r.sub.1))}{π.sub.R.sbsb.3.sup.c.sub.v.sbsb.3 (r.sub.1)-π.sub.R.sbsb.3.sup.c.sub.v.sbsb.3 (σ.sub.p (r.sub.1))} and wherein R 1 =<R 1 , V 1 , E 1 >, r 2 =<R 2 , V 2 , E 2 >, and r 3 =<R 3 , V 3 , E 3 > comprise three relations such that R 2 .OR right.R 1 , R 3 .OR right.R 1 , R 2 ∩R 3 =φ, V 2 .OR right.V 1 , V 3 .OR right.V 1 , and V 2 ∩V 3 =φ, and p denotes a null-intolerant predicate in R 1 .
Claim 26
Dependent Claim
60 words
The apparatus as set forth in claim 18 above, wherein the means for iteratively converting comprises means for applying a simplification expression to the SQL query comprising: ##EQU35## wherein X 1 =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 27
Dependent Claim
60 words
The apparatus as set forth in claim 18 above, wherein the means for iteratively converting comprises means for applying a simplification expression to the SQL query comprising: ##EQU36## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 28
Dependent Claim
60 words
The apparatus as set forth in claim 18 above, wherein the means for iteratively converting comprises means for applying a simplification expression to the SQL query comprising: ##EQU37## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 29
Dependent Claim
60 words
The apparatus as set forth in claim 18 above, wherein the means for iteratively converting comprises means for applying a simplification expression to the SQL query comprising: ##EQU38## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 30
Dependent Claim
60 words
The apparatus as set forth in claim 18 above, wherein the means for iteratively converting comprises means for applying a simplification expression to the SQL query comprising: ##EQU39## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 31
Dependent Claim
60 words
The apparatus as set forth in claim 18 above, wherein the means for iteratively converting comprises means for applying a simplification expression to the SQL query comprising: ##EQU40## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 32
Dependent Claim
60 words
The apparatus as set forth in claim 18 above, wherein the means for iteratively converting comprises means for applying a simplification expression to the SQL query comprising: ##EQU41## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 33
Dependent Claim
60 words
The apparatus as set forth in claim 18 above, wherein the means for iteratively converting comprises means for applying a simplification expression to the SQL query comprising: ##EQU42## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 34
Dependent Claim
60 words
The apparatus as set forth in claim 18 above, wherein the means for iteratively converting comprises means for applying a simplification expression to the SQL query comprising: ##EQU43## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 35
Dependent Claim
60 words
The apparatus as set forth in claim 18 above, wherein the means for iteratively converting comprises means for applying a simplification expression to the SQL query comprising: ##EQU44## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 36
Dependent Claim
60 words
The apparatus as set forth in claim 18 above, wherein the means for iteratively converting comprises means for applying a simplification expression to the SQL query comprising: ##EQU45## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 37
Dependent Claim
60 words
The apparatus as set forth in claim 18 above, wherein the means for iteratively converting comprises means for applying a simplification expression to the SQL query comprising: ##EQU46## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 38
Dependent Claim
60 words
The apparatus as set forth in claim 18 above, wherein the means for iteratively converting comprises means for applying a simplification expression to the SQL query comprising: ##EQU47## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 39
Dependent Claim
30 words
The method of claim 19 further comprising the step of iteratively applying, in the memory of the computer, a simplification identity to a SELECT DISTINCT operator in the SQL query.
Claim 40
Dependent Claim
32 words
The method of claim 19 further comprising the step of iteratively applying, in the memory of the computer, a simplification identity for a push-up of a GROUPBY operator in the SQL query.
Claim 41
Dependent Claim
138 words
The method of claim 19 wherein the GS operator, σ p * r 2 , r 3 !(r 1 ), of relation r 1 with respect to relations r 2 and r 3 comprises the relation <R 1 , V 1 , E'>, wherein: E'=σ.sub.p (r.sub.1){π.sub.R.sbsb.2.sup.c.sub.V.sbsb.2 (r.sub.1)-π.sub.R.sbsb.2.sup.c.sub.V.sbsb.2 (σ.sub.p (r.sub.1))}{π.sub.R.sbsb.3.sup.c.sub.V.sbsb.3 (r.sub.1)-π.sub.R.sbsb.3.sup.c.sub.V.sbsb.3 (σ.sub.p (r.sub.1))} and wherein r 1 =<R 1 , V 1 , E 1 >, r 2 =<R 2 , V 2 , E 2 >, and r 3 =<R 3 , V 3 , E 3 > comprise three relations such that R 2 .OR right.R 1 , R 3 .OR right.R 1 , R 2 ∩R 3 =φ, V 2 .OR right.V 1 , V 3 .OR right.V 1 , and V 2 ∩V 3 =φ, and p denotes a null-intolerant predicate in R 1 .
Claim 42
Dependent Claim
60 words
The method as set forth in claim 19 above, wherein the iteratively converting step comprises the step of applying a simplification expression to the SQL query comprising: ##EQU48## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X 1 and X j .
Claim 43
Dependent Claim
60 words
The method as set forth in claim 19 above, wherein the iteratively converting step comprises the step of applying a simplification expression to the SQL query comprising: ##EQU49## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 44
Dependent Claim
60 words
The method as set forth in claim 19 above, wherein the iteratively converting step comprises the step of applying a simplification expression to the SQL query comprising: ##EQU50## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 45
Dependent Claim
60 words
The method as set forth in claim 19 above, wherein the iteratively converting step comprises the step of applying a simplification expression to the SQL query comprising: ##EQU51## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 46
Dependent Claim
60 words
The method as set forth in claim 19 above, wherein the iteratively converting step comprises the step of applying a simplification expression to the SQL query comprising: ##EQU52## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 47
Dependent Claim
60 words
The method as set forth in claim 19 above, wherein the iteratively converting step comprises the step of applying a simplification expression to the SQL, query comprising: ##EQU53## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 48
Dependent Claim
60 words
The method as set forth in claim 19 above, wherein the iteratively converting step comprises the step of applying a simplification expression to the SQL query comprising: ##EQU54## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 49
Dependent Claim
60 words
The method as set forth in claim 19 above, wherein the iteratively converting step comprises the step of applying a simplification expression to the SQL query comprising: ##EQU55## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 50
Dependent Claim
60 words
The method as set forth in claim 19 above, wherein the iteratively converting step comprises the step of applying a simplification expression to the SQL query comprising: ##EQU56## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 51
Dependent Claim
60 words
The method as set forth in claim 19 above, wherein the iteratively converting step comprises the step of applying a simplification expression to the SQL query comprising: ##EQU57## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 52
Dependent Claim
60 words
The method as set forth in claim 19 above, wherein the iteratively converting step comprises the step of applying a simplification expression to the SQL query comprising: ##EQU58## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 53
Dependent Claim
60 words
The method as set forth in claim 19 above, wherein the iteratively converting step comprises the step of applying a simplification expression to the SQL query comprising: ##EQU59## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
Claim 54
Dependent Claim
60 words
The method as set forth in claim 19 above, wherein the iteratively converting step comprises the step of applying a simplification expression to the SQL query comprising: ##EQU60## wherein X i =<R i , V i , E i > are relational expressions for 1≦i≦3, and p i ,j denote the predicates between expressions X i and X j .
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
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| 3.5 Years (Year 4) | 2001-01-26 | 2001-07-28 | 2002-01-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-01-26 | 2005-07-28 | 2006-01-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-01-26 | 2009-07-28 | 2010-01-27 | $7700.00 | Window Closed / Lapsed |