In 3 tier architecture, client directly interacts with intermediate server and intermediate server will directly interact with database server.
A reference architecture consists of:Set of global external schemas.Global conceptual schema (GCS).Fragmentation schema and allocation schema.Set of schemas for each local DBMS conforming to 3-level ANSI/SPARC .Some levels may be missing, depending on levels of transparency supported.Can be homogeneous or heterogeneous.Gaurav SinghG.N.I.T MCA,GREATER NOIDAContact: 9458660007
A database is an organized collection of data, today typically in digital form. The data are typically organized to model relevant aspects of reality (for example, the availability of rooms in hotels), in a way that supports processes requiring this information (for example, finding a hotel with vacancies).The term database is correctly applied to the data and their supporting data structures, and not to the database management system (DBMS). The database data collection with DBMS is called adatabase system.
We know that three view-levels are described by means of three schemas. These schemas are stored in the data dictionary. In DBMS, each user refers only to its own external schema. Hence, the DBMS must transform a request on. a specified external schema into a request against conceptual schema, and then into a request against internal schema to store and retrieve data to and from the database. The process to convert a request (from external level) and the result between view levels is called mapping. The mapping defines the correspondence between three view levels. The mapping description is also stored in data dictionary. The DBMS is responsible for mapping between these three types of schemas. There are two types of mapping. (i) External-Conceptual mapping (ii) Conceptual-Internal mapping External-Conceptual Mapping An external-conceptual mapping defines the correspondence between a particular external view and the conceptual view. The external-conceptual mapping tells the DBMS which objects on the conceptual level correspond to the objects requested on a particular user's external view. If changes are made to either an external view or conceptual view, then mapping must be changed accordingly. Conceptual-Internal Mapping The conceptual-internal mapping defines the correspondence between the conceptual view and the internal view, i.e. database stored on the physical storage device. It describes how conceptual records are stored and retrieved to and from the storage device. This means that conceptual-internal mapping tells the DBMS that how the conceptual! records are physically represented. If the structure of the stored database is changed, then the mapping must be changed accordingly. It is the responsibility of DBA to manage such changes.
http://wiki.answers.com/Q/What_is_client_server_Architecture"e http://wiki.answers.com/Q/What_is_client_server_Architecture"eClient server architecture refers to a network architecture whereby every computer on the network is either a server or a client.
Physical schema,logical schema and sub schemas
The schema is the physical arrangement of the data as it appears in the DBMS. The sub-schema is the logical view of the data as it appears to the application program.
This is an architecture related to DBMS...wITH HELP OF THIS ARCHITECTURE, dATABASE DEGISNERS DEGISN DATBASE
The three levels of data abstraction in a DBMS are physical, logical, and view. Physical level: Describes how data is stored in the database, including details like data storage and access paths. Logical level: Focuses on the structure of the data in the database, including schemas, tables, and relationships. View level: Represents how users view the data, providing a customized and simplified representation of the data to different user groups.
A Multi-user DBMS Architecture is one big system of users and queries. The use of these are to over look and execute plans safely and does not violate and integrity constraints.
a representation of DBMS design. It helps to design, develop, implement, and maintain the database management system. A DBMS architecture allows dividing the database system into individual components that can be independently modified, changed, replaced, and
SCHEMA is the physical arrangement of the data as it appears in the DBMS. SUB-SCHEMA is the logical view of the data as it appears to the application program.
The schema is the physical arrangement of the data as it appears in the DBMS. The subschema is the logical view of the data as it appears to the application program.
combines everything into a single system including, DBMS software,hardware, application programs and user interface
A DBMS kernal is a type of database. It is usually used in the architecture business world and it consists of software and system-level data structures.
DBMS, Server, Storage media, Indexing, Encryption etc.. c
In 3 tier architecture, client directly interacts with intermediate server and intermediate server will directly interact with database server.