What is logical data independence with example?
Logical Data independence means if we add some new columns or remove some columns from table then the user view and programs should not change. For example: consider two users A & B. Both are selecting the fields “EmployeeNumber” and “EmployeeName”.
What is meant by physical and logical data independence explain how are they implemented?
Physical Data Independence is defined as the ability to make changes in the structure of the lowest level of the Database Management System (DBMS) without affecting the higher-level schemas. Hence, modification in the Physical level should not result in any changes in the Logical or View levels.
What is logical and physical data?
A logical data model is a model that describes data as much as possible, without regard to how they will be physically implemented in the database. In contrast, a physical data model is a model that represents how the actual database is built. Hence, this is the main difference between logical and physical data model.
What is physical data independence and why is it important?
Physical data independence gives us the freedom to modify the – Storage device, File structure, location of the database, etc without changing the definition of conceptual or view level.
What is physical data independence Mcq?
Physical Data Independence: The ability to change the internal schema without having to change the conceptual schema.
What is data independence explain logical data independence and physical data independence with respect to three layer architecture of DBMS?
Data independence can be explained using the three-schema architecture. Data independence refers characteristic of being able to modify the schema at one level of the database system without altering the schema at the next higher level.
What is logical data independence Mcq?
Logical Data Independence: The ability to change the conceptual schema without having to change the view level schema.
Why is logical data independence important?
So logical data independence means that all changes done to the database at the virtual or logical level should not change how the data is actually stored on the disk. Also the users view of the data should not be altered even if the data is changed in the logical level.
What is data independence and types of data independence?
Data independence is the ability to modify one level of a DBMS without affecting the next higher level’s data structure or access methods. It’s of two types, physical and logical.
What is description of logical schema?
A logical data model or logical schema is a data model of a specific problem domain expressed independently of a particular database management product or storage technology (physical data model) but in terms of data structures such as relational tables and columns, object-oriented classes, or XML tags.
Which one is example of physical data independence?
Examples of changes under Physical Data Independence : Switching to different data structures. Changing the access method. Modifying indexes. To change the compression techniques or hashing algorithms.
What is physical and logical schema?
Physical schema represents the actual connection to the data source or data target. Logical schema represents the logical name associated to that source or target.
What do you mean by physical data independence?
What do you mean by Physical Data Independence The ability to change the physical schema without changing the logical schema is called as Physical Data Independence.
What is logical data independence?
Logical Data Independence : Logical Data Independence is defined as the ability to make changes in the structure of the middle level of the Database Management System (DBMS) without affecting the highest-level schema or application programs.
What is the difference between logical independence and physical independence?
Compared to Logical Independence, it is easy to achieve physical data independence. With Physical independence, you can easily change the physical storage structures or devices with an effect on the conceptual schema.
What is data independence in DBMS?
Physical Data Independence is defined as the ability to make changes in the structure of the lowest level of the Database Management System (DBMS) without affecting the higher-level schemas. Hence, modification in the Physical level should not result in any changes in the Logical or View levels.
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