Application Development and Databases Essay Example | Topics and Well Written Essays - 4250 words

Application Development and Databases - Essay Example Permissions and authorization of users or processes are defined according to the policies of the business. An access control policy basically specifies a set of rules that describe the methods in which a client can access a server. Access control Matrix: An access control matrix is a simple method for the storage of access control information. It is a table in which each row represents a subject (user), each column represents an object (the object can be a file or a record etc.) and each entry is the set of access rights for that subject to that object. In general the access control matrix will be sparse, because most users will not have access rights to most objects. Every subject will, however, be mapped with every object (subject, object, rights). This approach can provide very fine grained security control. The problem is the more fine grained the control becomes the more entries are required in the table. In a big system the table can quickly become very big and difficult to manage and slow to search. Access control list: A different approach is to use capabilities and access control lists. The first method is to specify only the objects that a user may access. This approach is called a capability. It can be seen as a token giving the possessor certain rights to an object. The capability can be stored with the subject. A second method is to create a list that specifies which subjects can... The first method is to specify only the objects that a user may access. This approach is called a capability. It can be seen as a token giving the possessor certain rights to an object. The capability can be stored with the subject. A second method is to create a list that specifies which subjects can access an object, including their access rights. This approach is called an access control list (ACL). The ACL can be stored with the object or the resource. View based security: Currently, authorization mechanisms in SQL permit access control at the level of complete tables or columns, or on views. It is also possible to create views for specific users, restricting access to data by granting rights only to certain views & tables for each user. These allow those users access to only selected tuples of a table. However, complex role based access control conditions are difficult to implement. In some cases view security can be bypassed (if users have access to base tables). Also, management of security policy becomes complex by views. When a security policy is added, changed, or removed, it's difficult to determine what exactly to do with each view. An administrator cannot tell whether, by changing security policies through altering or dropping a view, he/she is breaking an application. Enforcing Access control privileges: i. Discretionary privileges: It is usually based on the granting and revoking of privileges. It is further divided into two classifications: 1. The Account level: At this level, the DBA specifies the particular privileges that each account holds independently of the relations in the database. Example: As the PMS is based on a centralized Oracle server, it must implement all the

Baroque Art Essay Example | Topics and Well Written Essays - 750 words

Baroque Art - Essay Example Whereas it is sometimes the case that a sculpture or is also skilled with the use of oil and canvas, this was especially true with regards to Geon Lorenzo Bernini. Tying in with the discussion and analysis of the means by which many of the Baroque artists were sponsored and promoted by the Catholic Church, Bernini is an especially good example of this. Rising rapidly among the ranks of the many artists of the time, Bernini soon attracted the attention of the papacy who commissioned him to perform several works of art. Blown away by his skill and prowess, both on canvas and with marble, Bernini became something of an artist of court for several successive popes. With such a notion in mind, it is easier to analyze the implied meaning and means by which bring me the expressed strong overt and subliminal religious tones within â€Å"The Ecstasy of St. Theresa† (Wilkin 31). Many scholars have considered this particular sculpture to be the beginning of high Roman Baroque art. In eff ect, even the casual observer can note the means by which the sculpture approach rates how the divine is interacting with the earthly via a theatrical mechanism. This in truth and into the affairs of men create something of a sensual, some even say orgasmic, juxtaposition of both the divine and human. However, rather than understanding the sculpture in too much of a temporal mindset, it was doubtless Bernini’s intention to express the pure joy and bliss that mankind could achieve when in communion with the divine. Although thematic elements between Bernini and Michelangelo Merisi da Caravaggio, represented within his artwork entitled â€Å"The Crucifixion of St. Peter†, are quite disparate, the reality of the matter is that the ideas represented and discussed are both highly spiritual in nature. At first glance, the reader can note the fact that a painstakingly detailed and imaginative oil painting of the crucifixion of St. Peter is displayed. Beyond the fact that St. Peter is obviously the only face within the portrait that can be seen, beyond the fact that St. Peter’s body, although supposedly aged at the time it is crucifixion, is unbelievably toned muscular, the viewer is also illustrated with the subliminal understanding that the weight of this crucifixion, both physical and mental, ways most heavily upon the perpetrators. As can be noted from an examination of the painting, it requires three strong young men to carry the body of an agent St. Peter to his final crucifixion (Marcussen 75). Each and every one of them are weighed down event under the heft of both