3 Query expression syntax and matching
Query expression syntax and matching describes the RISS Web Interface 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 33
•Word characters , page 33
•Letters and digits in different character sets , page 34
•Matching words, page 35
•Matching similar words, page 35
•Matching word sequences, page 36
•Boolean query expressions, page 37
•Nested Boolean query expressions, page 38
•Query expression examples, page 38
Query expressions
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 35.
•Look for word sequences in a document: words that are near each other, and in a particular order. See "Matching word sequences" on page 36.
•Combine query words using logical (Boolean) operators (AND, OR, NOT). See "Boolean query expressions" on page 37.
Together, these query constructs provide considerable power to find what you need, provided you learn to use them well.
The way query 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. Query 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. Query words can contain wildcards, such 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 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.
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