DBMS building blocks A DBMS includes four main parts: modeling language, data structure, database query language, and transaction mechanisms: 1)Modeling language A data modeling language to define the schema of each database hosted in the DBMS, according to the DBMS database model. The four most common types of models are the: * hierarchical model, * network model, * relational model, and * object model. 2)Data structure Data structures (fields, records, files and objects) optimized to deal with very large amounts of data stored on a permanent data storage device (which implies relatively slow access compared to volatile main memory) 3) Database query language A database query language and report writer allows users to interactively interrogate the database, analyze its data and update it according to the users privileges on data. It also controls the security of the database. Data security prevents unauthorized users from viewing or updating the database. Using pass