Database
A database is a collection of information that is organized so that it can be easily accessed, managed and updated.
The File Extension Of The Database Is .db
Data is organized into rows, columns and tables, and it is indexed to make it easier to find relevant information. Data gets updated, expanded and deleted as new information is added. Databases process workloads to create and update themselves, querying the data they contain and running applications against it.
- Centralized database
- Operational database
- End-user database
- Commercial database
- Personal database
- Distributed database
Centralized database
Users from different locations can access this database from a remote location at the central database, that store entire information and application programs at a central computing facility for processing. The application programs pick up the appropriate data from the database based on the transactions sent by the communications controller for processing the transaction.
Data validation and verification is carried out by the application programs at the central computer centre, and a registration number is allotted by the application programs located at the central facility. The local area office keeps on recording it and hardly does any processing.
Operational database
This is more of a basic form of data that contain information relating to the operations of an enterprise. Generally, such databases are organised on functional lines such as marketing, production, employees, etc.
End user database
End user is the user of a software, application or a product. This is a shared database which is shared by users and is meant for use by the end users, just like managers at different levels. They may not be concerned about the individual transactions as found in operational databases. This database is more about the summary of the information.
Commercial database
This is a database that contains information which external users may require. However, they will not be able to afford maintaining such huge database by themselves. It’s a paid service to the user as the databases are subject specific. The access to commercial database can be given through commercial links.
Some of the database service providers also offer databases on CD-ROMs and the updated versions of the databases are made available periodically. The databases on CD-ROMs have the advantage of reduced cost of communication.
Personal database
The personal databases are maintained, generally, on personal computers. They contain information that is meant for use only among a limited number of users, generally working in the same department.
Distributed database
These databases have contributions from the common databases as well as the data captured from the local operations. The data remains distributed at various sites in the organisation. As the sites are linked to each other with the help of communication links, the entire collection of data at all the sites constitutes the logical database of the organisation.
What is SQL?
- SQL stands for Structured Query Language
- SQL lets you access and manipulate databases
- SQL became a standard of the American National Standards Institute (ANSI) in 1986, and of the International Organization for Standardization (ISO) in 1987
What Can SQL do?
- SQL can execute queries against a database
- SQL can retrieve data from a database
- SQL can insert records in a database
- SQL can update records in a database
- SQL can delete records from a database
- SQL can create new databases
- SQL can create new tables in a database
- SQL can create stored procedures in a database
- SQL can create views in a database
- SQL can set permissions on tables, procedures, and views