Prepares for a search

Descrierea

yaz_search ( resource $id , string $type , string $query ) : bool

yaz_search() prepares for a search on the given connection.

Like yaz_connect() this function is non-blocking and only prepares for a search to be executed later when yaz_wait() is called.

Parametri

id

The connection resource returned by yaz_connect().

type

This parameter represents the query type - only "rpn" is supported now in which case the third argument specifies a Type-1 query in prefix query notation.

query

The RPN query is a textual representation of the Type-1 query as defined by the Z39.50 standard. However, in the text representation as used by YAZ a prefix notation is used, that is the operator precedes the operands. The query string is a sequence of tokens where white space is ignored unless surrounded by double quotes. Tokens beginning with an at-character (@) are considered operators, otherwise they are treated as search terms.

**RPN Operators**
Construct	Description
@and query1 query2	intersection of query1 and query2
@or query1 query2	union of query1 and query2
@not query1 query2	query1 and not query2
@set name	result set reference
@attrset set query	specifies attribute-set for query. This construction is only allowed once - in the beginning of the whole query
@attr [set] type=value query	applies attribute to query. The type and value are integers specifying the attribute-type and attribute-value respectively. The set, if given, specifies the attribute-set.

You can find information about attributes at the » Z39.50 Maintenance Agency site.

Notă:
If you would like to use a more friendly notation, use the CCL parser - functions yaz_ccl_conf() and yaz_ccl_parse().

Valorile întoarse

Întoarce valoarea TRUE în cazul succesului sau FALSE în cazul eșecului.

Exemple

Example #1 Query Examples

You can search for simple terms, like this:

computer

which matches documents where "computer" occur. No attributes are specified.

The query

"knuth donald"

matches documents where "knuth donald" occur (provided that the server supports phrase search).

This query applies two attributes for the same phrase.

@attr 1=1003 @attr 4=1 "knuth donald"

First attribute is type 1 (Bib-1 use), attribute value is 1003 (Author). Second attribute has is type 4 (structure), value 1 (phrase), so this should match documents where Donald Knuth is author.

The query

@and @or a b @not @or c d e

would in infix notation look like (a or b) and ((c or d) not e).

Another, more complex, one:

@attrset gils @and @attr 1=4 art @attr 1=2000 company

The query as a whole uses the GILS attributeset. The query matches documents where art occur in the title (GILS,BIB-1) and in which company occur as Distributor (GILS).