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.
________________defines the correspondence between an external view and the conceptual view. *
Architecture is the frame work of the Database Management System. They are simply classified into logical and physical.
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
Well, information mapping is when you look up and find new information and put it in a form of text e.g map whilst mind mapping is when you write the information you already know in a form of text.
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.
Subset mapping in DBMS refers to the process of mapping one subset of data from one database to another subset of data in another database. This is typically done to synchronize or transfer data between databases while ensuring that only relevant subsets are affected. It helps in maintaining data consistency and integrity between databases.
mapping is the procees of comparing the two
This is an architecture related to DBMS...wITH HELP OF THIS ARCHITECTURE, dATABASE DEGISNERS DEGISN DATBASE
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.
Architecture is the frame work of the Database Management System. They are simply classified into logical and physical.
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
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.
combines everything into a single system including, DBMS software,hardware, application programs and user interface
Physical schema,logical schema and sub schemas
In 3 tier architecture, client directly interacts with intermediate server and intermediate server will directly interact with database server.
database configuration monitoring, DBMS hardware configuration (a DBMS and related database may span computers, networks, and storage units) and related database mapping
Algebra is widely utilized in architecture. Architects use algebra to solve structural problems and issues. They also use it for planning, mapping, developing and implementation.