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What is the data schema in a database?
Logical Structure of database is know as database schema. All database entities are defined and relation between then is represented in structured way. It includes all constraints to be apply on each identity.
What relation and relation schema?
Relational Schema refers to meta-data elements which are used to describe structures and constraints of data representing a particular http://wiki.answers.com/Describe_the_differences_in_meaning_between_the_terms_relation_and_relation_schema#. Whereas a relation is a property or predicate that ranges over more than one argumentHere's some translation from "Relational Algebra" to http://wiki.answers.com/Describe_the_differences_in_meaning_between_the_terms_relation_and_relation_schema#terminology:"Relation" = Table."Relation Schema" = Table definition.So for example, the "schema" for the Person "relation" is: Person(FirstName, LastName, Age, Gender, Address)Also in relational Algebra, a "tuple" is a table row, and an "attribute" is a table column.
What is the cost of external and internal BGP routes?
external 20 internal 200
What is the difference between external stress and emotional stress?
External is out side emotional is in
In a script what does EXT. stand for?
EXT. Stands for External, as in external location (outside).
Which schema is called the view of a manager or other type of user?
external schema
How do different schema definition languages support the three schema architecture?
The three schema approach is used to build informational systems. The schema involves three different levels, which are the physical level, the conceptual level, and the external level.
How are the internal external and conceptual schemas related to concept of logical and physical data independence?
The internal schema represents the physical storage structure of data, the external schema represents how different users view the data, and the conceptual schema defines the logical structure of the entire database. Logical data independence means that the conceptual schema can change without affecting the external schemas, while physical data independence means that changes in the physical storage structures do not affect the conceptual or external schemas.
What are the 3 views of dbms?
A Database has three views. The External Schema: What the end user sees. The Internal Schema: What the programmers of the program see. The Conceptual Schema: The basic plan of the database. Most of the time this is in paper form as a Conceptual Schema Diagram (CSD)
Discuss the basic differences between external schema conceptual schema and internal schema?
The internal schema describes how the data will be physically stored and accessed, using the facilities provided by a particular DBMS. For example, the data might be organized so that all the insurance policies belonging to a given customer were stored close together, allowing them all to be retrieved into the computer's memory in a single operation. The conceptual schema (sometimes called the logical schema) describes the stored data in terms of the data model of the DBMS. In a relational DBMS, the conceptual schema describes all relations that are stored in the database The external schemasspecify views that enable different users of the data to see it in different ways. As a simple example, some users of policy data might not require details of the commission paid. By providing them with a view that excludes the Commission Rate column, we would not only shield them from unwanted (and perhaps unauthorized) information, but also insulate them from changes that might be made to the format of that data.by:mohammed abu Lamdy
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 dbms architecture?
1. External view : this is a highest level of abstraction as seen by user. This level of abstraction describes only the part of entry database. It is based on the conceptual model, is the end user view of data environment. Each external view described by means of a schema called an external schema or subschema. The external schema consists of the definition of the logical records and the relationships in the external view. The external schema also contains he method of deriving the objects in the external view from the objects in the conceptual view. The object include entities, attributes and relationships.2. Conceptual level : at this level of database abstraction all the database entities and the relationships among them are included. One conceptual view represents the entire database. the conceptual schema defines ths conceptual view. It there is only one conceptual schema per database. This schema also contains the method deriving from the objects in the conceptual view from the objects in the internal view.. at this level a database is described logically rather then physically in term of data structure.3. Internal(physical) level : this lowest level of abstraction. it closest to physical storage device. It describes how data are actually stored on the storage medium. The internal schema, which contains the definition of the stored record, the method representing the data fields, expresses the internal view and the access aids used.
What Logical data independence and physical data independence?
Logical Data Independence : The ability to change the logical schema without changing the external schema or application programs is called as Logical Data Independence.Physical Data Independence : The ability to change the physical schema without changing the logical schema is called as Physical Data Independence.Logical Data Independence :being able to maintain change at external layer without having to make any change at the concept.Physical Data Independence : we want to be able to make any change on the conceptual level to deal without any change at the physical
What Logical data independence and physical data?
Logical data independence refers to the ability to modify the conceptual schema without changing the external schemas or application programs. In contrast, physical data independence allows changes to the internal schema – like indexes and storage structures – without affecting the conceptual or external schemas.
What is star flake schema?
A starflake schema is a combination of a star schema and a snowflake schema. Starflake schemas are snowflake schemas where only some of the dimension tables have been denormalized. hardkingofflirt@gmail.com
What is the difference between logical and physical data independence?
The logical data independence is the ability to modify a logical schema without making external view or application program change. The physical data independence is the ability to modify a physical schema without making external view or application prrogram change.
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.
