Introduction to sql server
To obtain good performance, it is of course important to know
the software used.SQL Server is a management system database relational (RDBMS) that both meets the standards of this type of tool, and offer specific implementations
SQL Server is a management system relational database (RDBMS). It shares with its competitors in a standardized architecture, the result of decades of research in software engineering, conducted by researchers such as Edgar F. Codd, of course, Chris Date and Peter Chen for the relational model, but also Michael Stonebreaker and others for different methodologies and algorithms. RDBMS is usually a client-server application: A centralized server houses the RDBMS itself, whose responsibility is to ensure the storage of data, and respond to customer requests. On the server side, SQL Server consists of two main engines, respectively the relational engine, (query engine), and the storage engine, each of which contains different modules. The request from the client is supported by the relational engine, that evaluates the SQL code, check the metadata and privileges through an optimization phase to produce an implementation plan(query plan) optimized, and manages execution of the query. Extraction orders or actual writing are sent to storage engine, which is responsible, in addition to read and write pages of data, also manage transactional consistency, particularly through the lock. All communication between SQL Server and the physical server on which it is installed is supported by a layer of abstraction called SQLOS (OS Operating System), a kind of operating system embedded into motor. Separation of roles between the relational engine and the storage engine is a constant in the architecture of RDBMS, some even allow the choice
between different storage engines, such as MySQL.SQL Server nomenclature
It is useful to specify here the terms used in a SQL Server. For example it is noted that the various terms may seem troubling for a developer accustomed to Oracle because Oracle nomenclature is substantially different from that of SQL Server.SQL Server is a Windows service, which is called an instance. Thus, each installation of SQL Server on the same machine creates a new instance. One default instance is possible by server: other instances are called "named instances". It is thus possible to install different versions and publications on the same machine. Then, one instance may comprise a large number of databases that are highly isolated from each other, in particular in terms of safety. These databases contain patterns that are logical containers conforming to the SQL standard, and are in no way related to physical storage structures or database users. An object such as a table, view, stored procedure, etc.. belongs to one and only one schema.