From 65ac667d88f60abb43558cdffa2bde8b98398f26 Mon Sep 17 00:00:00 2001 From: boris Date: Sun, 21 Jan 2024 00:34:10 +0000 Subject: [PATCH] vault backup: 2024-01-21 00:34:10 --- Semester 2/Database Systems/Week 1/Week 1 Database Systems.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Semester 2/Database Systems/Week 1/Week 1 Database Systems.md b/Semester 2/Database Systems/Week 1/Week 1 Database Systems.md index 447fcc2..4bc2ac6 100644 --- a/Semester 2/Database Systems/Week 1/Week 1 Database Systems.md +++ b/Semester 2/Database Systems/Week 1/Week 1 Database Systems.md @@ -34,4 +34,4 @@ Purpose is to transform a query written in a high level language into correct an - Move SELECT operations down the tree - Apply more restrictive SELECT operations first ( eg. equalities before range queries ) - Replace Cartesian products followed by selection with theta joins ( eg. *sigma(f) ( RxS )* -> *R theta(f) S* ) -- Move PROJECT operations down the query tree ( add project operations as inputs to theta joins ) \ No newline at end of file +- Move PROJECT operations down the query tree ( add project operations as inputs to theta joins ). \ No newline at end of file