HP StorageWorks Reference Information Storage System V1.5 User Guide (T3559-96045, November 2008)
5 Q uery expression syntax and
matc hing
Query expression syntax and matching describes the syntax to use to search and retrieve archived
documents (files or email messages), and explains how queries are matched against documents.
Major topics include:
•
Query expressions, page 47
•
Word characters, page 47
•
Letters and digits in different character sets, page 48
•
Matching words, page 49
•
Matching similar words,page50
•
Matching word sequences, page 50
•
Boolean query expressions, page 53
•
Nested Boolean query expressions,page54
•
Query expression examples,page54
Query expressions
Query expressions can be as simple or as complex as needed. The essential idea behind document
retrie
val is that query words are compared with document words to find a match. You can also:
• Look for document words that are textually similar, but not necessarily identical, to query words.
See “Matching similar words” on page 50.
• Look f
or word sequences in a document: words that are near each other, and in a par ticular
ord e r. See “Matching word sequences”onpage50.
• Combine query words using logical (Boolean) operators (AND, OR, NOT). See
“Bool
ean query expressions”onpage53.
Toget
her, these query constructs provide considerab le power to find what you need, provided you
learn to use them well.
The way quer y expressions are interpreted is similar to the way documents are indexed when archived.
Text
is parsed (broken down) into words. Remaining characters are considered separators and ignored.
Quer
y expressions are fundamentally composed of words, no matter how complex the expression.
For indexing and searching, a word need not belong to a natural language, such as English. For
example, wt6_ht3 is a valid document word or query word. Quer y words can contain wildcards,
such
as in f??t.
Word characters
When the system examines a query expression to determine i ts words, some characters are not included
in query words, but are treated as word separators. When a document is archived, indexing determines
which document words are available for searching in the same way.
Learning the rules of creating query words means also learning the rules of document indexing and,
therefore, what words you can search for.
Version 1.5
47