It Database
A database is an organized collection of data. The data are typically organized to model relevant aspects of reality (for example, the availability of rooms in hotels), in a way that supports processes requiring this information (for example, finding a hotel with vacancies).
The term database is correctly applied to the data and their supporting data structures, and not to the database management system (DBMS). The database data collection with DBMS is called a database system.
The term database system implies that the data are managed to some level of quality (measured in terms of accuracy, availability, usability, and resilience) and this in turn often implies the use of a general-purpose database management system (DBMS).[1] A general-purpose DBMS is typically a complex software system that meets many usage requirements to properly maintain its databases which are often large and complex. The utilization of databases is now so widespread that virtually every technology and product relies on databases and DBMSs for its development and commercialization, or even may have DBMS software embedded in it. Also, organizations and companies, from small to large, depend heavily on databases for their operations.
Well known DBMSs include FoxPro, IBM DB2, Linter, Microsoft Access, Microsoft SQL Server, MySQL, Oracle, PostgreSQL and SQLite. A database is not generally portable across different DBMS, but different DBMSs can inter-operate to some degree by using standards like SQL and ODBC together to support a single application built over more than one database. A DBMS also needs to provide effective run-time execution to properly support (e.g., in terms of performance, availability, and security) as many database end-users as needed.
A way to classify databases involves the type of their contents, for example: bibliographic, document-text, statistical, or multimedia objects. Another way is by their application area, for example: accounting, music compositions, movies, banking, manufacturing, or insurance.
The term database may be narrowed to specify particular aspects of organized collection of data and may refer to the logical database, to the physical database as data content in computer data storage or to many other database sub-definitions.
Contents [hide]
1 History
1.1 Database concept
1.2 Evolution of database and DBMS technology
1.2.1 General-purpose DBMS
1.2.1.1 Types of people involved
1.2.2 Database machines and appliances
1.3 Database research
2 Database type examples
3 Major database usage requirements
3.1 Functional requirements
3.2 Operational requirements
3.2.1 Availability
3.2.2 Performance
3.2.3 Isolation between users
3.2.4 Recovery from failure and disaster
3.2.5 Backup and restore
3.2.6 Data independence
4 Major database functional areas
4.1 Data models
4.1.1 Early data models
4.1.1.1 Hierarchical model
4.1.1.2 Network model
4.1.1.3 Inverted file model
4.1.2 Relational model
4.1.3 Entity-relationship model
4.1.4 Object model
4.1.5 Object relational model
4.1.6 XML as a database data model
4.1.7 Other database models
4.2 Database languages
4.2.1 SQL for the Relational model
4.2.2 OQL for the Object model
4.2.3 XQuery for the XML model
4.3 Database architecture
4.4 Database security
4.4.1 Access control
4.4.2 Data security
4.4.3 Database audit
4.5 Database design
4.5.1 Entities and relationships
4.5.2 Database normalization
4.6 Database building, maintaining, and tuning
4.7 Miscellaneous areas
4.7.1 Database migration between DBMSs
5 Implementation: Database management systems
5.1 DBMS architecture: major DBMS components
5.2 Database storage
5.2.1 Data
5.2.1.1 Coding the data and Error-correcting codes
5.2.1.2 Data compression
5.2.1.3 Data encryption
5.2.2 Data storage types
5.2.2.1 Storage metrics
5.2.2.2 Protecting storage device content: Device mirroring (replication) and RAID
5.2.3 Database storage layout
5.2.3.1 Database storage hierarchy
5.2.3.2 Data structures
5.2.3.3 Application data and DBMS data
5.2.3.4 Database indexing
5.2.3.5 Database data clustering
5.2.3.6 Database materialized views
5.2.3.7 Database and database object replication
5.3 Database transactions
5.3.1 ACID rules
5.3.2 Isolation, concurrency control, and locking
5.4 Query optimization
5.5 DBMS support for the development and maintenance of a database and its application
6 See also
7 References
8 Further reading
9 External links
A database is an organized collection of data. The data are typically organized to model relevant aspects of reality (for example, the availability of rooms in hotels), in a way that supports processes requiring this information (for example, finding a hotel with vacancies).
The term database is correctly applied to the data and their supporting data structures, and not to the database management system (DBMS). The database data collection with DBMS is called a database system.
The term database system implies that the data are managed to some level of quality (measured in terms of accuracy, availability, usability, and resilience) and this in turn often implies the use of a general-purpose database management system (DBMS).[1] A general-purpose DBMS is typically a complex software system that meets many usage requirements to properly maintain its databases which are often large and complex. The utilization of databases is now so widespread that virtually every technology and product relies on databases and DBMSs for its development and commercialization, or even may have DBMS software embedded in it. Also, organizations and companies, from small to large, depend heavily on databases for their operations.
Well known DBMSs include FoxPro, IBM DB2, Linter, Microsoft Access, Microsoft SQL Server, MySQL, Oracle, PostgreSQL and SQLite. A database is not generally portable across different DBMS, but different DBMSs can inter-operate to some degree by using standards like SQL and ODBC together to support a single application built over more than one database. A DBMS also needs to provide effective run-time execution to properly support (e.g., in terms of performance, availability, and security) as many database end-users as needed.
A way to classify databases involves the type of their contents, for example: bibliographic, document-text, statistical, or multimedia objects. Another way is by their application area, for example: accounting, music compositions, movies, banking, manufacturing, or insurance.
The term database may be narrowed to specify particular aspects of organized collection of data and may refer to the logical database, to the physical database as data content in computer data storage or to many other database sub-definitions.
Contents [hide]
1 History
1.1 Database concept
1.2 Evolution of database and DBMS technology
1.2.1 General-purpose DBMS
1.2.1.1 Types of people involved
1.2.2 Database machines and appliances
1.3 Database research
2 Database type examples
3 Major database usage requirements
3.1 Functional requirements
3.2 Operational requirements
3.2.1 Availability
3.2.2 Performance
3.2.3 Isolation between users
3.2.4 Recovery from failure and disaster
3.2.5 Backup and restore
3.2.6 Data independence
4 Major database functional areas
4.1 Data models
4.1.1 Early data models
4.1.1.1 Hierarchical model
4.1.1.2 Network model
4.1.1.3 Inverted file model
4.1.2 Relational model
4.1.3 Entity-relationship model
4.1.4 Object model
4.1.5 Object relational model
4.1.6 XML as a database data model
4.1.7 Other database models
4.2 Database languages
4.2.1 SQL for the Relational model
4.2.2 OQL for the Object model
4.2.3 XQuery for the XML model
4.3 Database architecture
4.4 Database security
4.4.1 Access control
4.4.2 Data security
4.4.3 Database audit
4.5 Database design
4.5.1 Entities and relationships
4.5.2 Database normalization
4.6 Database building, maintaining, and tuning
4.7 Miscellaneous areas
4.7.1 Database migration between DBMSs
5 Implementation: Database management systems
5.1 DBMS architecture: major DBMS components
5.2 Database storage
5.2.1 Data
5.2.1.1 Coding the data and Error-correcting codes
5.2.1.2 Data compression
5.2.1.3 Data encryption
5.2.2 Data storage types
5.2.2.1 Storage metrics
5.2.2.2 Protecting storage device content: Device mirroring (replication) and RAID
5.2.3 Database storage layout
5.2.3.1 Database storage hierarchy
5.2.3.2 Data structures
5.2.3.3 Application data and DBMS data
5.2.3.4 Database indexing
5.2.3.5 Database data clustering
5.2.3.6 Database materialized views
5.2.3.7 Database and database object replication
5.3 Database transactions
5.3.1 ACID rules
5.3.2 Isolation, concurrency control, and locking
5.4 Query optimization
5.5 DBMS support for the development and maintenance of a database and its application
6 See also
7 References
8 Further reading
9 External links
Images
Images
Images
Images
Images
Images
Images
Images
Images
Images
.jpg)
Images
Images
No comments:
Post a Comment