6f24cc0632
In some cases, the `rule.adoc` at root of a rule is never included anywhere and thus is dead code. It's a maintenance cost by itself, but also it misses opportunities to inline code that seems used by two documents when in fact only one document is actually rendered. And this missed opportunity, in turn, stops us from applying the correct language tag on the code samples.
64 lines
1.9 KiB
Plaintext
64 lines
1.9 KiB
Plaintext
== Why is this an issue?
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``++WHERE++`` clause conditions that reinforce or contradict the definitions of their columns are useless; they are always either unconditionally true or unconditionally false. For instance, there's no point in including ``++AND column IS NOT NULL++`` if the column is defined as non-null.
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*Noteworthy*
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This rule raises issues only when a *Data Dictionary* is provided during the analysis. See https://docs.sonarqube.org/latest/analysis/languages/plsql/
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=== Noncompliant code example
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[source,sql]
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----
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CREATE TABLE product
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(id INT,
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name VARCHAR(6) NOT NULL,
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mfg_name VARCHAR(6),
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mfg_id INT
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...
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SELECT name, price
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FROM product
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WHERE name is not null -- Noncompliant; always true. This column is NOT NULL
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AND mfg_name = 'Too long name' -- Noncompliant; always false. This column can contain only 6 characters
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----
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ifdef::env-github,rspecator-view[]
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'''
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== Implementation Specification
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(visible only on this page)
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=== Message
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* Based on the definition of "ccc", this condition is always ["TRUE"|"FALSE"].
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* Based on the constraints on "ccc", this condition is always ["TRUE"|"FALSE"].
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* Change this condition so that it does not always evaluate to ["TRUE"|"FALSE"].
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=== Highlighting
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problem condition
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'''
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== Comments And Links
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(visible only on this page)
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=== relates to: S2583
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=== relates to: S3633
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=== on 17 Jun 2016, 15:03:20 Ann Campbell wrote:
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from \https://www.researchgate.net/publication/222432151_Semantic_errors_in_SQL_queries_A_quite_complete_list:
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Error 27: Uncorrelated EXISTS-subqueries.If an EXISTS-subquery makes no reference to a tuple variable from theouter query, is is either globally true or globally false. This is a very unusualbehaviour. Actually, uncorrelated EXISTS-subqueries are simply missing joinconditions (possibly for anti-joins).
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Not sure if we want to handle this here or in RSPEC-3647
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endif::env-github,rspecator-view[]
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