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What is the difference between physical data model and logical data model in systems analysis?
The Logical Data Model (LDM) is derived from the Conceptual Data Model (CDM).
The CDM consists of the major entity sets and the relationship sets, and does not state anything about the attributes of the entity sets.
The LDM consists of the Entity Sets, their attributes, the Relationship sets, the cardinality, type of replationship, etc.
The Physical Data Model (PDM) consists of the Entity Sets (Tables), their attributes (columns of tables), the Relationship sets (whose attributes are also mapped to columns of tables), along with the Datatype of the columns, the various integrity constraints, etc.
Erwin calls the conversion / transformation of LDM => PDM as Forward Engineering which further leads to the actual code generation and the conversion of Code => PDM => LDM as Reverse Engineering!
Though the question says specifically about Erwin, the above explanation is independent of the datamodeling tool used for the purpose.
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What is the difference between network architecture and network topology?
The difference between architecture and topology is logical vs physical. Architecture is about the logical design of something. Topology is about the physical elements required to enable the architectural design. The difference between architecture and topology is logical vs physical. Architecture is about the logical design of something. Topology is about the physical elements required to enable the architectural design. The difference between architecture and topology is logical vs physical. Architecture is about the logical design of something. Topology is about the physical elements required to enable the architectural design.
2.5 What is the difference between logical data independence 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.
Is a logical unit of data and is a physical unit of data?
A logical unit of data is a virtual representation of data while a physical unit of data is the actual storage of data on a physical device. The logical unit of data is how data is organized and manipulated from a software perspective, while the physical unit of data is how data is stored on hardware such as disks or memory.
Show the difference bw 3-levels of data abstraction in DBMS?
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.
Is it harder to achieve logical data independence or physical data independence?
It is generally considered more difficult to achieve logical data independence compared to physical data independence. Logical data independence involves separating the conceptual structure of the data from the physical storage aspects, which can be complex depending on the database design. Physical data independence primarily deals with shielding the application from changes in the storage structure, which is usually more straightforward to achieve.
Difference between physical and logical DFD?
difference between physical and logical data flow diagrams.
What is difference between physical data flow diagram and logical data flow diagram?
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What are the difference between logical and physical tag?
While physical tags are also referred to as presentational mark-up, logical tags are useless for appearances. Physical tags are newer versions while logical tags are old and concentrate on content.
What is the difference between physical and logical topology?
Physical topology are says how the wire are interconnected, while Logical topology is how the network behaves and interoperates.Sk wasim ul HaqueKharagpur, Madpur
What is the difference between network architecture and network topology?
The difference between architecture and topology is logical vs physical. Architecture is about the logical design of something. Topology is about the physical elements required to enable the architectural design. The difference between architecture and topology is logical vs physical. Architecture is about the logical design of something. Topology is about the physical elements required to enable the architectural design. The difference between architecture and topology is logical vs physical. Architecture is about the logical design of something. Topology is about the physical elements required to enable the architectural design.
What is the difference between virtual logical and physical address spaces?
The concept of a logical address space is simply involved the process of mapping the Logical addresses to their Physical Addresses . Logical addresses are generated by the CPU; also referred to as virtual addresses.while Physical Address is the actual address of the data stored on the physical device and mapped by MMU.
What is the difference between a logical view and a physical view of data?
The logical view presents data as they would be perceived by end users or business specialists, whereas the physical view shows how data are actually organized and structured on physical storage media.
What is difference between logical file and physical file?
* Physical file (PF) contains the data and have only one record format. Logical file (LF) is a view of the physical file which does not contain any data may be based on one physical file or more then one physical file. Logical file can have more then one record format. Logical can be non join or join logical file. Performance becomes better if you use the logical file in the program.
What Difference between logical versus physical address storage?
A physical address is concrete and never changes. It is set in memory. A logical address is made up of a base pointer and an offset.It keeps programs running parallel and not intertwining.
What is the difference between biological and biopotential amplifiers?
difference is logical and potential
The difference between intuitive thinking and logical thinking?
The Difference is Logical Is with your head, Intuative is with your heart. Which is Mind over Heart.
What is the difference between historical and logical context?
History is not real, logical things are real, like if a dog is logical
