Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Information systems store structured information in a Database. A database is created, accessed, and manipulated via a Database management system (DBMS). DBMS theory and practice is an important subdicipline of computer science. Many databases are used to share data among a number ...Full description
Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Information systems store structured information in a Database. A database is created, accessed, and manipulated via a Database management system (DBMS). DBMS theory and practice is an important subdicipline of computer science. Many databases are used to share data among a number of concurrent users. The classic example is an airline reservation system. When multiple users share a database, the DBMS must decide which user can make modifications at any given time. The basic approach it to create a lock when a user accesses data, and release the lock when the user is no longer accessing the data.