introduction to DBMS

• data - raw facts, unprocessed data
• information - data processed to reveal meaning
• good information characteristic - relevant, timely, just sufficient, organized, accurate, cost effective, verifiable
• database - integrated computer structures that stores end user data (raw facts) and metadata (data about data)
• DBMS (database management system) - collection of programs that control access to data and manages database structures, make data management more effective and efficient, possible to share data among multiple users and applicators
• advantages of DBMS - probability of data inconsistency is greatly reduced, reduce data redundancy, end user have better access to more and better managed data
• types of databases - single user, desktop, multi-user, workgroup, enterprise
• single user - only one user at a time
• desktop - single-user database running on personal computer
• multi-user - support multiple user at a time
• workgroup - support small group
• enterprise - support large group
• classified by location - centralized (support data located at a single site, one central location, simple management, potential single point of failure), distributed (support data distributed across several sites, distributed across multiple locations, complex management, improved fault tolerance)
• classified by use - transactional (supports a company day-to-day operations), data warehouse (stores data to generate information required to make strategies decision, structure different, often use to store historical data)
• N - accept special character
• var - flexible length