Database Assignment Example | Topics and Well Written Essays - 1500 words

Database - Assignment ExampleThe second layer is diversely treated by database modeling languages. Nevertheless, there are common features, especially example constructors. A common approach in most models is the generic definition of operations according to the structure of the type. The inductive specification of structuring is based on base types and type constructors. A type constructor is a function from types to a new type. The constructor can be supplemented with a selector for recovery (like Select) with a retrieval expression and update functions (like Insert, Delete, and Update) for value mapping from the new type to the comp iodinnt types or to the new type, with correctness criteria and rules for validation, with default rules current date for data assignment, with one or several user re instaurations, and with a physical representation or properties of the physical representation. A base type is an algebraic structure B = (Dom(B) Op(B) Pred(B)) with a name, aSet of valu es in a domain, a set of operations and a set of predicates. A class BC on the base type is a collection of elements from Dom (B). Usually, BC is required to be a set (DIETRICH, 2011). It can be also a list (denoted by ) multi-set (.), tree etc. Classes may be changed by applying operations. Elements of a class may be classified by the predicates. The value set can be discrete or continuous, impermanent or infinite. We typically assume discrete value sets. Typical predicates are comparison predicates such(prenominal) as 6= ? =. Typical functions are arithmetic functions such as, - and x. The set of integers is given by the Integer Set. The base type is extended to a data type by explicit definition of properties of the under-lying value sets. precision and accuracy data can be precise to a certain extent. Precision is the degree of refinement in the calculations. Accuracy is a measure of how repeatable the assignment of values for properties is. Granularity Scales can be fine or coarse. The accuracy of data depends on the granularity of the domain which has been chosen for the representation of properties. order of magnitude The ordering of values of a given domain can be based on ordering schemes such as lexicographic, geographic or chronological ordering or on exact ordering such as orderings on natural numbers. The ordering can also be based on ontologies or categories. Scales have a range with lowest values and highest values. These values can be finite or infinite, if they are finite then floodlight or underflow errors might be the result of a computation. Classification The data can be used for representation of classifications the classification can be linear, hierarchical, etc. The classification can be mono-hierarchical or poly-hierarchical, mono-dimensional, poly-dimensional, analytical, synthetically or even monothetic. The classification can be based on ontologies and can be maintain with thesauri. Presentation The data type can be mapped to different representation types dependent on several parameters. For instance, in Web applications, the format chosen for presentation types of pictures depends on the capacity of the channel, on the compression etc. The presentation might be linear or hierarchical, and it can be layered. Implementation The implementation the put type depends on the properties of the DBMS. The implementatio