Give a definition of human-computer interface?
Human-computer interface (HCI) The means of communication between a human user and a computer system, referring in particular to the use of input/output devices with supporting software. Devices of increasing sophistication are becoming available to mediate the human-computer interaction. These include graphics devices, touch-sensitive devices, and voice-input devices. They have to be configured in a way that will facilitate an efficient and desirable interaction between a person and the computer. Artificial intelligence techniques of knowledge representation may be used to model the user of a computer system, and so offer the opportunity to give personalized advice on its use. The design of the machine interface may incorporate expert-system techniques to offer powerful knowledge-based computing to the user.
HCI is a branch of the science of ergonomics, and is concerned especially with the relationship between workstations and their operators. The aim is to develop acceptable standards for such aspects as display resolution, use of color, and navigation around an application.
The terms human-system interface (HSI), human-machine interface (HMI), and man-machine interface (MMI) are all used as synonyms.
What functions are carried system Database?
A database is an organized collection of data. It is the collection of schemas, tables, queries, reports, views, and other objects. The data are typically organized to model aspects of reality in a way that supports processes requiring information, such as modelling the availability of rooms in hotels in a way that supports finding a hotel with vacancies.
A database management system (DBMS) is a computer software application that interacts with the user, other applications, and the database itself to capture and analyze data. A general-purpose DBMS is designed to allow the definition, creation, querying, update, and administration of databases. Well-known DBMSs include MySQL, PostgreSQL, MongoDB, Microsoft SQL Server, Oracle, Sybase, SAP HANA, and IBM DB2. A database is not generally portable across different DBMSs, but different DBMS can interoperate by using standards such as SQL and ODBC or JDBC to allow a single application to work with more than one DBMS. Database management systems are often classified according to the database model that they support; the most popular database systems since the 1980s have all supported the relational model as represented by the SQL language. Sometimes a DBMS is loosely referred to as a 'database'.
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DBMS performs several important functions that guarantee the integrity and consistency of the data in the database. The most important functions of Database Management System are
1. Data Dictionary Management
One of the most important Function of The Database Management System is Data Dictionary Management.
DBMS stores definitions of the data elements and their relationships (metadata) in a data dictionary.
So, all programs that access the data in the database work through the DBMS. The DBMS uses the data dictionary to look up the required data component structures and relationships which relieves you from coding such complex relationships in each program.
Аdditionally, any changes made in a database structure are automatically recorded in the data dictionary, thereby freeing you from having to modify all of the programs that access the changed structure.
In other words, the DBMS system provides data abstraction, and it removes structural and data dependence from the system.
2. Data Storage Management
The DBMS creates and manages the complex structures required for data storage, thus relieving you from the difficult task of defining and programming the physical data characteristics.
A modern DBMS system provides storage not only for the data, but also for related data entry forms or screen definitions, report definitions, data validation rules, procedural code, structures to handle video and picture formats, and so on.
Data storage management is also important for database performance tuning. Performance tuning relates to the activities that make the database perform more efficiently in terms of storage and access speed. So, the data storage management is another important function of Database Management System.
3. Data transformation and presentation
The DBMS transforms entered data in to required data structures. The DBMS relieves you of the chore of making a distinction between the logical data format and the physical data format. That is, the DBMS formats the physically retrieved data to make it conform to the user’s logical expectations.
4. Security Management
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Security Management is another important function of the Database Management System. The DBMS creates a security system that enforces user security and data privacy. Security rules determine which users can access the database, which data items each user can access, and which data operations (read, add, delete, or modify) the user can perform. This is especially important in multiuser database systems.
5. Multi User Access Control
To provide data integrity and data consistency, the DBMS uses sophisticated algorithms to ensure that multiple users can access the database concurrently without compromising the integrity of the database.
6. Backup and Recovery Management
The DBMS provides backup and data recovery to ensure data safety and integrity. Current DBMS systems provide special utilities that allow the DBA to perform routine and special backup and restore procedures. Recovery management deals with the recovery of the database after a failure, such as a bad sector in the disk or a power failure. Such capability is critical to preserving the database’s integrity.
7. Data Integrity Management
The DBMS promotes and enforces integrity rules, thus minimizing data redundancy and maximizing data consistency. The data relationships stored in the data dictionary are used to enforce data integrity. Ensuring data integrity is especially important in transaction-oriented database systems.
8. Database Access Languages and Application Programming Interfaces
The DBMS provides data access through a query language. A query language is a non procedural language—one that lets the user specify what must be done without having to specify how it is to be done. Structured Query Language (SQL) is the defacto query language and data access standard supported by the majority of DBMS vendors.
9. Database Communication Interfaces
Current-generation DBMS's accept end-user requests via multiple, different network environments. For example, the DBMS might provide access to the database via the Internet through the use of Web browsers such as Mozilla Firefox or Microsoft Internet Explorer. In this environment, communications can be accomplished in several ways:
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- End users can generate answers to queries by filling in screen forms through their preferred Web browser.
- The DBMS can automatically publish predefined reports on a Website.
- The DBMS can connect to third-party systems to distribute information via e-mail or other productivity applications.
What is a DBMS?
A database management system (DBMS) is system software for creating and managing databases. The DBMS provides users and programmers with a systematic way to create, retrieve, update and manage data.
A DBMS makes it possible for end users to create, read, update and delete data in a database. The DBMS essentially serves as an interface between the database and end users or application programs, ensuring that data is consistently organized and remains easily accessible.
The DBMS manages three important things: the data, the database engine that allows data to be accessed, locked and modified -- and the database schema, which defines the database’s logical structure. These three foundational elements help provide concurrency, security, data integrity and uniform administration 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 perhaps most useful for providing a centralized view of data that can be accessed by multiple users, from multiple 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 handles 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 concerned 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.
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With relational DBMSs (RDBMSs), this API is SQL, a standard programming language for defining, protecting and accessing data in a RDBMS.
Popular types of DBMSes
Popular database models and their management systems include:
Relational database management system (RDMS) - adaptable to most use cases, but RDBMS Tier-1 products can be quite expensive.
NoSQL DBMS - well-suited for loosely defined data structures that may evolve 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 responsible for providing and maintaining the DBMS.
Advantages 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 multiple users in a controlled manner.
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