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Subject: [OASIS Issue Tracker] Commented: (CMIS-660) Clarification needed onthe use of quotes in a CONTAINS() query to search on phrases
[ http://tools.oasis-open.org/issues/browse/CMIS-660?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=19652#action_19652 ]
Jens Hübel commented on CMIS-660:
---------------------------------
One more suggestion:
Would it help to remove the quotes around <text search expression> and instead have them around <word>?
<word> then is just a special case of <phrase>.
<text search predicate> ::= CONTAINS "(" [ <qualifier> "," ] <text search expression> ")"
<phrase> ::= <word> // one of <phrase> <word> now obsolete
<word> ::= <quote> [ {<char>} ... ] <quote>
or perhaps even better:
<word> ::= <character string literal> // referring to SQL-92
Examples:
CONTAINS('Elephant') // simplest form
CONTAINS(cmis:document, 'Elephant' OR 'Leopard') // or
CONTAINS(cmis:document, 'Elephant' 'Leopard') // and
CONTAINS(cmis:document, 'Elephant' AND 'Leopard') // and as potential extension for CMIS 1.1?
CONTAINS(cmis:document, 'My Elephant') // exact phrase
CONTAINS('That\'s me') // exact phrase with an escaped single quote
It would give us a better separation between keywords (OR) and string literals. The comma could still be used if we need more parameters in CONTAINS. <conjunct> enforces a space as separator so we don't run in the two-quotes-sequence issue.
We also need to clarify section 2.1.10.3 Escaping:
"... will be used to escape characters within quoted strings ..."
What does that mean?
CMISQL grammar refers to SQL-92 grammar symbol <character string literal>
SQL-92 (http://www.contrib.andrew.cmu.edu/~shadow/sql/sql1992.txt) says:
<quote symbol> ::= <quote><quote>
<quote> ::= '
"Each <quote symbol> contained in <character string literal> represents a single <quote> in both the value and the length of the <character string literal>."
So do we have both then, meaning: That's me. becomes That\'\'s me.? Is it a replacement: That\'s me.?
What exactly is a quoted string? A <character string literal>, a <phrase>, a <text search expression>? All?
We already had interoperability issues in this area.
> Clarification needed on the use of quotes in a CONTAINS() query to search on phrases
> ------------------------------------------------------------------------------------
>
> Key: CMIS-660
> URL: http://tools.oasis-open.org/issues/browse/CMIS-660
> Project: OASIS Content Management Interoperability Services (CMIS) TC
> Issue Type: Improvement
> Components: Domain Model
> Affects Versions: Draft 0.70
> Reporter: Jane Doong
> Assignee: Ethan Gur-esh
> Priority: Minor
>
> Clarification needed on the use of quotes in a CONTAINS() query to search on phrases.
> Spec:
> 2575 BNF grammar structure:: CONTAINS ( [ <qualifier> ,] ' <text search expression> ' )
> 2413 <phrase> ::= <quote> <word> [ {<space> <word>} ... ] <quote>
> 2422 <quote> ::= "'" !! Single-quote only, consistent with SQL-92 string literal
> 2597 Within a word or phrase, each (single-)quote must also be escaped by a preceding backslash "\"
> The spec specifically states that <quote> is single-quote only.
> My questions is on specifying a phrase inside the CONTAINS().
> Since the entire text search expression is enclosed in single quotes,
> I question whether a phrase should again be enclosed in single quotes, or should it be in double-quotes.
> According to spec:
> Word search: CONTAINS('house')
> Phrase search : CONTAINS(' 'my house' ')
> Should phrases be in double-quotes? ==> CONTAINS(' "my house" ')
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