A database system has several subsystems. • The storage manager subsystem provides the interface between the low- level data stored ◦ in the database and the application programs and queries submitted to the system. The query processor subsystem compiles and executes DDL and DML statements. ◦ • Transaction management ensures that the database remains in a consistent (correct) state despite system failures. The transaction manager ensures that concurrent transaction executions proceed without conflicting. The architecture of a database system is greatly influenced by the underlying computer • system on which the database system runs. Database systems can be centralized, or where one server machine executes work on behalf of multiple client machines. Database systems can also be designed to exploit parallel computer architectures. Distributed databases span multiple geographically separated machines. Database applications are typically broken up into a front-end part that runs at client • machines and a part that runs at the back end. In two-tier architectures, the front end directly communicates with a database running at the back end. In three-tier architectures, the back Knowledge-discovery techniques attempt to discover automatically statistical rules and • patterns from data. The field of data mining combines knowledge- discovery techniques invented by artificial intelligence researchers and statistical analysts, with efficient implementation techniques that enable them to be used on extremely large databases. There are four different types of database-system users, differentiated by the way they • expect to interact with the system. Different types of user interfaces have been designed for the different types of users. Topic #2 Relational Data Model – Review Table Relation schema Referential integrity • • • Relation Relation instance constraint • • Tuple Keys Schema diagram • • • Attribute key language • ◦ • Domain Candidate key Procedural language • ◦ ◦ Atomic domain Primary key Nonprocedural • ◦ ◦ Null value Foreign key language • • Database schema Referencing relation Operations on relations • ◦ • Database instance Referenced relation Selection of tuples • ◦ ◦
• A database system has several subsystems. ◦ The storage manager subsystem provides the interface between the low- level data stored in the database and the application programs and queries submitted to the system. ◦ The query processor subsystem compiles and executes DDL and DML statements. • Transaction management ensures that the database remains in a consistent (correct) state despite system failures. The transaction manager ensures that concurrent transaction executions proceed without conflicting. • The architecture of a database system is greatly influenced by the underlying computer system on which the database system runs. Database systems can be centralized, or where one server machine executes work on behalf of multiple client machines. Database systems can also be designed to exploit parallel computer architectures. Distributed databases span multiple geographically separated machines. • Database applications are typically broken up into a front-end part that runs at client machines and a part that runs at the back end. In two-tier architectures, the front end directly communicates with a database running at the back end. In three-tier architectures, the back • Knowledge-discovery techniques attempt to discover automatically statistical rules and patterns from data. The field of data mining combines knowledge- discovery techniques invented by artificial intelligence researchers and statistical analysts, with efficient implementation techniques that enable them to be used on extremely large databases. • There are four different types of database-system users, differentiated by the way they expect to interact with the system. Different types of user interfaces have been designed for the different types of users. Topic #2 – Relational Data Model Review • Table • Relation • Tuple • Attribute • Domain • Atomic domain • Null value • Database schema • Database instance • Relation schema • Relation instance • Keys ◦ key ◦ Candidate key ◦ Primary key • Foreign key ◦ Referencing relation ◦ Referenced relation • Referential integrity constraint • Schema diagram • language ◦ Procedural language ◦ Nonprocedural language • Operations on relations ◦ Selection of tuples
Coverage%20Terms%20and%20Summary-1.docx