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A conceptual data model is a high-level overview of the structure and relationships within a database. It focuses on the entities, attributes, and relationships between entities without going into the specifics of how the data will be implemented in a physical database. It serves as a blueprint for designing a database system.
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What are the Classification of data model?
Data models can be classified into three main categories: conceptual data model (high-level view of the data and its relationships), logical data model (detailed structure of the data and relationships), and physical data model (implementation of the database design on a specific database management system).
A detailed description of all data used in the database IS CALLED?
A detailed description of all data used in the database is called a data dictionary. It centralizes information about the structure of the database, including data types, relationships, constraints, and metadata. This resource is crucial for understanding and managing the database effectively.
What is data abstraction in DBMS?
Purpose of database users with an abstract view of the data that is system hides certain details of how the data are stored and maintained. It gives an architecture is to separate the user applications and the physical database.
2.5 What is the difference between logical data independence and physical data independence?
Logical data independence refers to the ability to change the conceptual schema without affecting the external schema or application programs. Physical data independence, on the other hand, refers to the ability to change the physical schema without affecting the conceptual schema. This allows changes in the storage structure or access methods without changing how data is viewed or accessed by applications.
What is logical data independence and why is it important?
Logical data independence refers to the ability to make changes to the conceptual schema of a database system without affecting the external schema or applications that access the data. It is important because it allows for flexibility in adapting the database structure to evolving business requirements without disrupting existing applications or users. This separation of logical layers simplifies maintenance, enhances system scalability, and reduces the risk of data inconsistencies during schema modifications.
Difference between schema sub schema and instance in DBMS in detail?
the overall logical data base description is referred to as a schema. it is sometimes also referred to as an overall modal of the data, a conceptual modal of the data, a conceptual schema
What is an e-r diagram?
Entity Relationship Diagram is a high-level description of a conceptual data model.
What makes the database effective?
The Conceptual Data Model
What is global conceptual schema?
The enterprise view of the data is described by the global conceptual schema (GCS), which is global because it describes the logical structure of the data at all the sites.
Distinguish between logical data independence and physical data independence?
logical data : refer to the immunity of the external scheme towards changes in the conceptual scheme.physical data: refer to the immunity of the conceptual scheme towards changes in the internal scheme.
What converts highlevel language into lomlevel language?
Compiler.
Explain the difference of internal external and conceptual schemas how are these schema layers related to the concept of logical and physical data independence?
External schemas allows data access to be customized (and authorized) at the level of individual users or groups of users. Conceptual (logical) schemas describes all the data that is actually stored in the database. While there are several views for a given database, there is exactly one conceptual schema to all users. Internal (physical) schemas summarize how the relations described in the conceptual schema are actually stored on disk (or other physical media). External schemas provide logical data independence, while conceptual schemas offer physical data independence.
Which type of the data model is being used presently?
There are three levels of data modeling. They are conceptual, logical, and physical."Conceptual" means a definition of the problem, "logical" means a design of a solution to the problem, and "physical" means the solution of the problem.
Mapping in DBMS architecture?
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.
Example of conceptual literature?
Conceptual literature explores the possibilities; it calls us to look at the world and ourselves, discovering and rediscovering life and what it means to live, love, hate, explore, and create. From me, conceptual literature is tapping into the co-creating with the divine.
In which Highlevel Data Link Control exchange mode can combined stations in a point-to-point configuration initiate transmission without requiring permission to use a line?
Asynchronous balanced mode (ABM)
Basic differences between conceptual schema and a physical schema?
* Conceptual - a model that captured the essential data that needed to be stored and the relationships between elements * * ** Physical - the on disk representation of data that accounts for layout, partitioning, index, space management, etc.
