GIS is a robust set of tools for collecting and retrieving data,
transforming it into information and displaying that information on maps taken
from the real world. The integration
of GPS, RS and other data modelling technologies provides
information which helps in dealing with the changes that are integral for
environmental protection, surveillance and disaster management.
Geographic
information system (GIS) is software that converts data into productive
information by getting data from GPS and RS, and then analyzes the data and
displays it as productive information. It gives an inexpensive way of map
production, displaying the information on the map and makes the analysis easier.
Remote Sensing (RS) is
about collecting and measuring data without having a direct contact with the
objects; use of satellite, aircraft and now drones are used to capture this
information of earth’s surface.It saves time and money from the expensive
physical field surveys. For environmental studies (RS) is more commonly used
technology.
A database management system provides the ability for many different users to share data and process resources. But as there can be many different users, there are many different database needs. The question now is: How can a single, unified database meet the differing requirement of so many users?
A DBMS minimizes these problems by providing two views of the database data: a logical (external) view and physical (internal) view. The logical view/user’s view, of a database program represents data in a format that is meaningful to a user and to the software programs that process those data. That is, the logical view tells the user, in user terms, what is in the database. The physical view deals with the actual, physical arrangement and location of data in the direct access storage devices(DASDs). Database specialists use the physical view to make efficient use of storage and processing resources. With the logical view users can see data differently from how they are stored, and they do not want to know all the technical details of physical storage. After all, a business user is primarily interested in using the information, not in how it is stored.
One strength of a DBMS is that while there is only one physical view of the data, there can be an endless number of different logical views. This feature allows users to see database information in a more business-related way rather than from a technical, processing viewpoint. Thus the logical view refers to the way user views data, and the physical view to the way the data are physically stored and processed...
DBMS Features and capabilities
Alternatively, and especially in connection with the relational model of database management, the relation between attributes drawn from a specified set of domains can be seen as being primary. For instance, the database might indicate that a car that was originally "red" might fade to "pink" in time, provided it was of some particular "make" with an inferior paint job. Such higher arity relationships provide information on all of the underlying domains at the same time, with none of them being privileged above the others.
Throughout recent history specialized databases have existed for scientific, geospatial, imaging, document storage and like uses. Functionality drawn from such applications has lately begun appearing in mainstream DBMSs as well. However, the main focus there, at least when aimed at the commercial data processing market, is still on descriptive attributes on repetitive record structures.
Thus, the DBMSs of today roll together frequently-needed services or features of attribute management. By externalizing such functionality to the DBMS, applications effectively share code with each other and are relieved of much internal complexity. Features commonly offered by database management systems include:
- Query ability
- Querying is the process of requesting attribute information from various perspectives and combinations of factors. Example: "How many 2-door cars in Texas are green?" A database query language and report writer allow users to interactively interrogate the database, analyze its data and update it according to the users privileges on data.
- Backup and replication
- Copies of attributes need to be made regularly in case primary disks or other equipment fails. A periodic copy of attributes may also be created for a distant organization that cannot readily access the original. DBMS usually provide utilities to facilitate the process of extracting and disseminating attribute sets. When data is replicated between database servers, so that the information remains consistent throughout the database system and users cannot tell or even know which server in the DBMS they are using, the system is said to exhibit replication transparency.
- Rule enforcement
- Often one wants to apply rules to attributes so that the attributes are clean and reliable. For example, we may have a rule that says each car can have only one engine associated with it (identified by Engine Number). If somebody tries to associate a second engine with a given car, we want the DBMS to deny such a request and display an error message. However, with changes in the model specification such as, in this example, hybrid gas-electric cars, rules may need to change. Ideally such rules should be able to be added and removed as needed without significant data layout redesign.
- Security
- Often it is desirable to limit who can see or change which attributes or groups of attributes. This may be managed directly by individual, or by the assignment of individuals and privileges to groups, or (in the most elaborate models) through the assignment of individuals and groups to roles which are then granted entitlements.
- Computation
- There are common computations requested on attributes such as counting, summing, averaging, sorting, grouping, cross-referencing, etc. Rather than have each computer application implement these from scratch, they can rely on the DBMS to supply such calculations.
- Change and access logging
- Often one wants to know who accessed what attributes, what was changed, and when it was changed. Logging services allow this by keeping a record of access occurrences and changes.
- Automated optimization
- If there are frequently occurring usage patterns or requests, some DBMS can adjust themselves to improve the speed of those interactions. In some cases the DBMS will merely provide tools to monitor performance, allowing a human expert to make the necessary adjustments after reviewing the statistics collected.
Meta-data repository
Metadata is data describing data. For example, a listing that describes what attributes are allowed to be in data sets is called "meta-information". The meta-data is also known as data about data.
DBMS Current Trends
As of 1998 database management was in need of new style databases to solve current database management problems. Researchers realized that the old trends of database management were becoming too complex and there was a need for automated configuration and management [3]. Surajit Chaudhuri, Gerhard Weikum and Michael Stonebraker, were the pioneers that dramatically affected the thought of database management systems [3]. They believed that database management needed a more modular approach and that there are so many specifications needs for various users [3]. Since this new development process of database management we currently have endless possibilities. Database management is no longer limited to “monolithic entities” [3]. Many solutions have developed to satisfy individual needs of users. Development of numerous database options has created flexible solutions in database management. Today there are several ways database management has affected the technology world as we know it. Organizations demand for directory services has become an extreme necessity as organizations grow. Businesses are now able to use directory services that provided prompt searches for their company information [3]. Mobile devices are not only able to store contact information of users but have grown to bigger capabilities. Mobile technology is able to cache large information that is used for computers and is able to display it on smaller devices [3]. Web searches have even been affected with database management. Search engine queries are able to locate data within the World Wide Web [3]. Retailers have also benefited from the developments with data warehousing. These companies are able to record customer transactions made within their business [3]. Online transactions have become tremendously popular with the e-business world. Consumers and businesses are able to make payments securely on company websites. None of these current developments would have been possible without the evolution of database management. Even with all the progress and current trends of database management, there will always be a need for new development as specifications and needs grow.
Examples of Database Management Systems
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