The logical schema of a database is the result of the logical design of databases.
Logical design is part of the database design process, along with conceptual database design and physical database design.
A logical database schema is a description of the database structure that a DBMS can process.
The logical database schema depends on a type of DBMS (relational, network, hierarchical…), but not on a specific DBMS. In other words, a logical data model or 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. This is opposed to a conceptual data model, which describes the semantics of an organization without reference to technology.
more details
Logical data models represent the abstract structure of an information domain. They are often diagrammatic in nature and are most typically used in business processes that seek to capture things of importance to an organization and how they relate to each other. Once validated and approved, the logical data model can become the basis for a physical data model and form the design of a database.
Logical data models should be based on the structures identified in a previous conceptual data model, as this describes the semantics of the information context, which should also reflect the logical model. Still, because the logical data model anticipates implementation on a specific computing system, the content of the logical data model is adjusted to achieve certain efficiencies.
The term «Logical Data Model» is sometimes used synonymously with «domain model» or as an alternative to domain model. Although the two concepts are closely related and have overlapping goals, a domain model focuses more on capturing the concepts in the problem domain than on the structure of the data associated with that domain.
Brief history
When ANSI first introduced the idea of a logical scheme in 1975, the options were hierarchical and network. The relational model-in which data is described in terms of tables and columns-had just been recognized as a theory of data organization, but no software existed to support that approach. Since then, an object-oriented approach to data modeling has also been introduced, in which data is described in terms of classes, attributes, and associations.
Reasons to build a logical data structure
– Helps common understanding of business data elements and requirements
– Provides the basis for the design of a database
– Facilitates the avoidance of data redundancy and thus avoids inconsistencies in data transactions
– Facilitates data reuse and sharing
– Decreases the time and cost of development and maintenance
– Confirms a logical process model and assists in impact analysis.
Logical data model vs physical data model
A logical data model is sometimes incorrectly called a physical data model, which is not what the people at ANSI had in mind. The physical design of a database involves extensive use of a particular database management technology. For example, a table/column layout could be implemented on a collection of computers, located in different parts of the world. That belongs to the domain of the physical model.
related terminology
database design
DBMS (database management system)
Quote the definition:
Alegsa.com.ar (2019). Database Logical Schema Definition – ALEGSA 2019-03-28 url: https:///Dic/database logic scheme.php
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