Fuzzy Querying Capability at Core of a RDBMS - Advanced Database Query Systems - page 174

Box 5.

#define RelationFuzzyCompId 2857
CATALOG(pg_fuzzycomp,2857) BKI_BOOTSTRAP BKI_WITHOUT_OIDS {
NameData compname; // comparator name

int2 compbegd; // domain range begin

int2 compendd; // domain range end

NameData compmin; // support's left bound

NameData compcore1; // core's left bound (included)

NameData compcore2; // core's right bound (included)

NameData compmax; // support's right bound

int2 comptype; // comparator type

NameData compdisd; // discrete domain

text complist[1]; // compare list name

} FormData_pg_fuzzycomp;

Box 6.

#define RelationFuzzyConnId 2880
CATALOG(pg_fuzzyconn,2880) BKI_BOOTSTRAP BKI_WITHOUT_OIDS{
NameData connname; // connector name

NameData connexpr; // defining expresion

} FormData_pg_fuzzyconn;

Box 7.

#define RelationFuzzyQuanId 2878 CATALOG(pg_fuzzyquan,2878) BKI_BOOTSTRAP
BKI_WITHOUT_OIDS{ NameData uanname; // quantifier name
NameData quanminfp; // support's left bound

NameData quancore1; // core's left bound (included)

NameData quancore2; // core's right bound (included)

NameData quanmaxfp; // support's right bound

int2 quantypefp; // shape 1(trapz.) 2(increases) 3(decreases)

int2 quantypefq; // nature 1 (absolute) 2 (proportional)

} FormData_pg_fuzzyquan;

fuzzy condition, generated structure is a Fuzzy Parse Tree. It is characterized by the presence of fuzzy
terms nodes as defined in previous section.
Let's illustrate this abstract structure by means of the the following query:

SELECT FirstName, LastName FROM STUDENT WHERE age = young