Database Program Translation - Information Systems Reengineering, Integration and Normalization - page 217

If more than one attributes are selected, union operator is used to get the result.
For example:
URRWQRGH#DWWULEXWH_URRWQRGH#DWWULEXWH
The search conditions in the SQL query are transformed to predicates to refine the
set of nodes selected by the location step.
5. Transform XPath query data into SQL query data
The XML document returned from XMLDB is formatted into tabular format be-
fore return to user. The format of the result is based on the data stored in the table
table_column_seq (prepared in pre-processed schema translation). The following
shows the pseudo code for translating SQL query to XPath query:
352&('85(%UHDNGRZQ64/4XHU\64/4XHU\
,QLWLDOL]HWKHDUUD\LGHQWLILHUDUUD\
,QLWLDOL]HWKHDUUD\UHODWLRQDUUD\WRHPSW\DUUD\
,QLWLDOL]HWKHDUUD\VHDUFKFRQGLWLRQDUUD\WRHPSW\DUUD\
,QLWLDOL]HWKHDUUD\;4/TXHU\DUUD\WRHPSW\DUUD\
([WUDFWWKHSRUWLRQRIWKH64/4XHU\IURPNH\ZRUG
µ6(/(&7¶WRNH\ZRUGµ)520¶LQWRYDULDEOHLGHQWLILHUV
([WUDFWWKHSRUWLRQRIWKH64/4XHU\IURPNH\ZRUG
µ)520¶WRNH\ZRUGµ:+(5(¶LQWRYDULDEOHUHODWLRQV
([WUDFWWKHSRUWLRQRIWKH64/4XHU\IURPNH\ZRUG
µ:+(5(¶ WRWKHQ HQG RIWKHTXHU\LQWR YDULDEOHVHDUFK
FRQGLWLRQV
Identify each search condition from the variable search conditions and put them into
the search-condition array.
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%(*,1
5HPRYHWKHVHDUFKFRQGLWLRQIURPVHDUFKFRQGLWLRQ
DUUD\LILWLVDWDEOHMRLQ
,)VHDUFKFRQGLWLRQLVWKHIXQFWLRQµ(;,676¶7+(1
%UHDNGRZQWKHVXETXHU\ZLWKLQµ(;,676¶E\
UHFXUVLYHO\FDOOLQJSURFHGXUH%UHDNGRZQ64/4XHU\
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(1',)
(1'
Identify each identifier from the variable identifier and put them intoidentifier array