https://xinlin-z.github.io/tags/sql/ Recent content in SQL on Xinlin's Blog Hugo -- 0.147.8 en-us Sun, 19 Jul 2026 12:29:25 +1200 https://xinlin-z.github.io/posts/dbms/ Sun, 19 Jul 2026 12:29:25 +1200 https://xinlin-z.github.io/posts/dbms/ <h2 id="database-design">Database Design</h2> <p>Database is a system to manage data, which is built on file system offered by OS. Broadly speaking, there are two cases in which database is utilized:</p> <ol> <li><strong>OLTP</strong>, OnLine Transaction Process, for supporting daily business</li> <li><strong>OLAP</strong>, OnLine Analysis Process, for supporting data analysis in <strong>Data Warehouse</strong></li> </ol> <p>Database design is actually the design of data tables (entities) and their relationships. The design purposes are:</p> <ol> <li>store information without unnecessary redundancy</li> <li>retrieve information easily and fast</li> </ol> <h3 id="normal-form-nf">Normal Form (NF)</h3> <p>NFs are used to eliminate information redundancy. The higher NF, the less redundancy.</p>