Search results
Results from the WOW.Com Content Network
Class diagram showing generalization between the superclass Person and the two subclasses Student and Professor. The generalization relationship—also known as the inheritance or "is a" relationship—captures the idea of one class, the so-called subclass, being a specialized form of the other (the superclass, super type, or base class). Where ...
The entity–relationship model proposes a technique that produces entity–relationship diagrams (ERDs), which can be employed to capture information about data model entity types, relationships and cardinality. A Crow's foot shows a one-to-many relationship. Alternatively a single line represents a one-to-one relationship. [4]
The network model organizes data using two fundamental concepts, called records and sets. Records contain fields (which may be organized hierarchically, as in the programming language COBOL). Sets (not to be confused with mathematical sets) define one-to-many relationships between records: one owner, many members. A record may be an owner in ...
Realization - Realization shows the relationship between an Interface and the class that provides the implementation for the interface. Reference-Request - The input to the system for finding the related abstracts from different operations (Add, Del, Mod, Inq.). Request could be for only one for every operation; Response - The output of the ...
an arrow from an entity set to a relationship set indicates a key constraint, i.e. injectivity: each entity of the entity set can participate in at most one relationship in the relationship set; a thick line indicates both, i.e. bijectivity: each entity in the entity set is involved in exactly one relationship.
The RDF data model [1] is similar to classical conceptual modeling approaches (such as entity–relationship or class diagrams).It is based on the idea of making statements about resources (in particular web resources) in expressions of the form subject–predicate–object, known as triples.
Data structure diagram and a data dictionary. A data structure diagram is a diagram type that is used to depict the structure of data elements in the data dictionary. The data structure diagram is a graphical alternative to the composition specifications within such data dictionary entries. [1] The data structure diagrams is a predecessor of ...
A named set of data values (fixed, or possibly infinite in number) all of the same data type, upon which the actual value for an attribute instance is drawn. Every attribute must be defined on exactly one underlying domain. Multiple attributes may be based on the same underlying domain. Attributes