Fix wrong pred evaluated with wrong plan - Githubissues

don-tay / simpledb

Subset of SQL-compliant DBMS

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Fix wrong pred evaluated with wrong plan #49

Closed don-tay closed 2 years ago

don-tay commented 2 years ago

Changes in this PR

[x] Bug fix
[ ] New feature
[ ] Breaking change of an existing feature
[ ] Refactor/Performance enhancements

Overview

Predicate not found in plan being used in forming joins
To fix this, only predicates found in table have their joins attempted on
Otherwise, default to using cross product followed by selectscan. Hence, correctness is guaranteed.

This fixes the following query when avg num of rows in table is 50 (in #47):

select sid,sname,eid,sectid from student, enroll, section where sid=studentid and sectionid=sectid