database

• Databases evolved from computer file systems
• Understanding file system characteristics is important
• Databases solve many problems encountered in data management
• Databases are used in modern settings involving data management in Business, Research, and Administration
• Data are meaningful facts, text, graphics, images, sound, video segments
• Information is the result of processing raw data to reveal its meaning
• Raw data must be formatted for storage, processing, and presentation
• Data are the foundation of information, which is the bedrock of knowledge
• Data management focuses on proper generation, storage, and retrieval of data
• Metadata are data that describe the properties or characteristics of other data
• Database is a shared, integrated computer structure that stores a collection of end-user data and metadata
• DBMS (Database Management System) is a software package that stores and manages databases
• DBMS architecture can be centralized, decentralized, or hierarchical
• DBMS architecture can be single-tier, two-tier, or three-tier
• Database schema is the skeleton structure that represents the logical view of the entire database
• Physical Database Schema pertains to the actual storage of data like files, indices, etc
• Logical Database Schema defines all the logical constraints that need to be applied on the data stored
• Database Instance is a state of operational database with data at any given time
• Logical Data Independence liberalizes itself from actual data stored on the disk
• Physical Data Independence is the power to change the physical data without impacting the schema or logical data
• A database system normally contains metadata to locate and retrieve data easily