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A database abstraction layer (DBAL[1] or DAL) is an application programming interface which unifies the communication between a computer application and databases such as SQL Server, IBM Db2, MySQL, PostgreSQL, Oracle or SQLite. Traditionally, all database vendors provide their own interface that is tailored to their products.
Remarkably, the selected option, as well as all the other candidates, had an architecture composed of three layers of increasing scope: data link (to handle different types of physical media), network (to handle different types of networks) and internetwork (to handle a network of networks), each layer with its own address space.
Database administrators, who must decide what information to keep in a database, use the logical level of abstraction. View level: The highest level of abstraction describes only part of the entire database. Even though the logical level uses simpler structures, complexity remains because of the variety of information stored in a large database.
Database design. Database design is the organization of data according to a database model. The designer determines what data must be stored and how the data elements interrelate. With this information, they can begin to fit the data to the database model. [1] A database management system manages the data accordingly.
In addition, a description of the database technology to be employed must be generated, as well as a description of the processes that are to manipulate the data. It is also important to design interfaces to the data by other systems, as well as a design for the infrastructure that is to support common data operations (i.e. emergency procedures ...
It is supported on all major operating systems, including Windows, Linux, macOS, FreeBSD, and OpenBSD, and handles a range of workloads from single machines to data warehouses, data lakes, [14] or web services with many concurrent users. The PostgreSQL Global Development Group focuses only on developing a database engine and closely related ...
The relational model (RM) is an approach to managing data using a structure and language consistent with first-order predicate logic, first described in 1969 by English computer scientist Edgar F. Codd, [1][2] where all data is represented in terms of tuples, grouped into relations. A database organized in terms of the relational model is a ...
1. Physical layer. The Open Systems Interconnection (OSI) model is a reference model from the International Organization for Standardization (ISO) that "provides a common basis for the coordination of standards development for the purpose of systems interconnection." [2] In the OSI reference model, the communications between systems are split ...