Wednesday, June 29, 2016

Introduction to DBMS SQL Server

A database management system (DBMS) is system software for crafting and managing databases. The DBMS offers users and programmers with an organized way to create, retrieve, update and accomplish data.
A DBMS makes it possible for end users to create, read, update and delete data in a database. The DBMS basically serves as an interface between the database and end users or application programs, confirming that data is consistently prepared and remains simply accessible.
The DBMS accomplishes three important things: the data, the database engine that allows data to be accessed, locked and modified and the database diagram, which defines the database’s logical structure. These three foundational elements help provide concurrency, security, data integrity and uniform management procedures. Typical database administration tasks supported by the DBMS include change management, performance monitoring/tuning and backup and recovery. Many database management systems are also responsible for automated rollbacks, restarts and recovery as well as the logging and auditing of activity.
The DBMS is possibly most useful for providing a unified view of data that can be accessed by numerous users, from various locations, in a controlled manner. A DBMS can limit what data the end user sees, as well as how that end user can view the data, providing many views of a single database schema. End users and software programs are free from having to understand where the data is physically located or on what type of storage media it resides because the DBMS levers all requests.
The DBMS can offer both logical and physical data independence. That means it can protect users and applications from needing to know where data is stored or having to be worried about changes to the physical structure of data (storage and hardware). As long as programs use the application programming interface (API) for the database that is provided by the DBMS, developers won't have to modify programs just because changes have been made to the database.
With relational DBMSs (RDBMSs), this API is SQL, a standard programming language for defining, protecting and accessing data in a RDBMS.
Common types of DBMS systems:-
Popular database models and their management systems include:
Relational database management system (RDMS) - flexible to most use cases, but RDBMSTier-1 products can be quite expensive.
NoSQL DBMS - compatible for loosely defined data structures that may change over time. 
In-memory database management system (IMDBMS) - provides faster response times and better performance.
Columnar database management system (CDBMS) - well-suited for data warehouses that have a large number of similar data items.
Cloud-based data management system - the cloud service provider is accountable for providing and maintaining the DBMS.
Benefits of a DBMS

Using a DBMS to store and manage data comes with advantages, but also overhead. One of the biggest advantages of using a DBMS is that it lets end users and application programmers access and use the same data while managing data integrity. Data is better protected and maintained when it can be shared using a DBMS instead of creating new iterations of the same data stored in new files for every new application. The DBMS provides a central store of data that can be accessed by numerous users in a controlled manner.