HP StorageWorks Reference Information Storage System V1.1 User Guide (February 2005)

Query expression syntax and matching Chapter 6: Query syntax and matching
HP StorageWorks Reference Information Storage System User Guide, February 2005 6-3
Query expression syntax and matching
Query expressions are composed of words
Query expressions can be as simple or as complex as needed. The essential
idea behind document retrieval 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 6-7
• Look for word sequences in a document: words that are near each other,
and in a particular order – see
Matching word sequences , on page 6-8
• Combine query words using logical (Boolean) operators ( AND , OR , NOT ) –
see
Boolean query expressions , on page 6-9
Together, using these query constructs provide considerable power to find
what you need.
The way a query expression is interpreted is similar to how documents are
indexed when they are archived. The text is parsed (broken down) into words.
The remaining characters are ignored, as separators. A query expression is
fundamentally composed of words, no matter how complex it is.
For indexing and searching, a word need not belong to a natural language,
such as English. For example,
wt6_ht3 is a legitimate document word or query
word. Some query words even contain wildcards, as in
f??t .
Word characters
When the system examines a query expression to determine its words, some
characters are not included in query words, but are treated as word
separators. When a document is archived, indexing determines the document
words, available for searching, in the same way.
Learning the rules of creating query words thus means learning also the rules
of document indexing and therefore just what words you can search for.