Presentation on theme: "Manajemen Basis Data Pertemuan Matakuliah: M0264/Manajemen Basis Data Tahun: 2008."— Presentation transcript:
Manajemen Basis Data Pertemuan Matakuliah: M0264/Manajemen Basis Data Tahun: 2008
Bina Nusantara The System Catalog (Sistem Katalog) Overview of Query Processing (Pengenalan Evaluasi Operator) Algorithm for Relational Operation (Logika Operasi Relasi) Introduction to Query Optimization (Pengenalan Query Optimization) Objectives
Bina Nusantara Catalog Tables / Data Dictionary Informasi in Katalog : Tabel Index View How Catalogs are stored The System Catalog
Bina Nusantara Overview of Query Processing Activities involved in retrieving data from the database. Aims of QP: –transform query written in high-level language (e.g. SQL), into correct and efficient execution strategy expressed in low-level language (implementing RA); –execute strategy to retrieve required data.
Bina Nusantara Overview of Query Processing Phases of Query Processing
Bina Nusantara Algorithm for Relational Operation Selection ( ) Selects a subset of rows from relation. Projection ( ) Deletes unwanted columns from relation. Join ( ) Allows us to combine two relations. Set-difference ( ) Tuples in reln. 1, but not in reln. 2. Union ( ) Tuples in reln. 1 and in reln. 2. Aggregation ( SUM, MIN, etc.) and GROUP BY
Bina Nusantara Introduction to Query Optimization Activity of choosing an efficient execution strategy for processing query. As there are many equivalent transformations of same high-level query, aim of QO is to choose one that minimizes resource usage. Generally, reduce total execution time of query. May also reduce response time of query. Problem computationally intractable with large number of relations, so strategy adopted is reduced to finding near optimum solution.
Bina Nusantara Introduction to Query Optimization Query Query Parser Query Optimizer Plan Generator Plan Cost Estimator Catalog Manager Query Plan Evaluator
Bina Nusantara Introduction to Query Optimization