CompSci

Overview In a deductive database system we typically specify rules through a declarative language — a language in which we specify what to achieve rather than how to achieve it. An inference engine (or deduction mechanism ) within the system can deduce new facts from the database by interpreting these rules. The model used for deductive databases is closely related to the relational data model, and particularly to the domain relational calculus formalism (see Section 6.6). It is also related to the field of logic programming and the Prolog language. The deductive database work based on logic has used Prolog as a starting point. A variation of Prolog called Datalog is used to define rules declaratively in conjunction with an existing set of relations, which are themselves treated as literals in the language. Although the language structure of Datalog resembles that of Prolog, its operational semantics—that is, how a Datalog program is executed—is still different. A deductive ...

Introduction to Spatial Databases •        Spatial databases incorporate functionality that provides support for databases that keep track of objects in a multidimensional space. •        For example, cartographic databases that store maps include two-dimensional spatial descriptions of their objects—from countries and states to rivers, cities, roads, seas, and so on. •        The systems that manage geographic data and related applications are known as Geographical Information Systems (GIS). •        Spatial Database are used in areas such as environmental applications, transportation systems, emergency response systems, and battle management. •        Also they are use as meteorological databases for weather information, are three-dimensional, since temperatures and other meteorological information are related to three-di...

Introduction Temporal databases, encompass all database applications that require some aspect of time when organizing their information. They provide a good example to illustrate the need for developing a set of unifying concepts for application developers to use. Temporal database applications have been developed since the early days of database usage. In creating these applications, it is mainly left to the application designers and developers to discover, design, program, and implement the temporal concepts they need. There are many examples of applications where some aspect of time is needed to maintain the information in a database. These include healthcare, where patient histories need to be maintained; insurance, where claims and accident histories are required as well as information about the times when insurance policies are in effect; reservation systems in general (hotel, airline, car rental, train, and so on), where information on the dates and times when reservat...

Introduction This unit introduces database concepts for some of the common features that are needed by advanced applications and are being used widely. We will cover active rules that are used in active database applications. This concept comes with database trigger. A database trigger is a procedural code that is automatically executed in response to certain events. Triggers are fired when data is modified. Triggers are existed in early versions of SQL specifications and now are available with SQL-99 and later standards. Generalized Model for Active Databases and Oracle Triggers The model that has been used to specify active database rules is referred to as the Event-Condition-Action (ECA) model. A rule in the ECA model has three components: The event(s) that triggers the rule:These events are usually database update operations that are explicitly applied to the database. The condition that determines whether the rule action should be executed: Once the triggering e...

Data Mining 1) The _____________ accessed is usually a different version from that of the original operational database. A) data                  B) Query               C) Output             D) None of these Correct Ans:   Data 2) The ______________   of the data mining query probably is not a subset of the database. A) data                  B) Query               C) Output             D) None of these Correct Ans:   Output 3) A ________________ makes a prediction about values of data using known results found from different data. A) Classification Model   ...