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Composite entity is a Java EE Software design pattern and it is used to model, represent, and manage a set of interrelated persistent objects rather than representing them as individual fine-grained entity beans, and also a composite entity bean represents a graph of objects.
There is no B → A relationship. B → C direct dependency relationship exists. Then the functional dependency A → C is a transitive dependency (which follows the axiom of transitivity). In database normalization, one of the important features of third normal form is that it excludes certain types of transitive dependencies.
For example, think of A as Authors, and B as Books. An Author can write several Books, and a Book can be written by several Authors. In a relational database management system, such relationships are usually implemented by means of an associative table (also known as join table, junction table or cross-reference table), say, AB with two one-to-many relationships A → AB and B → AB.
The terms schema matching and mapping are often used interchangeably for a database process. For this article, we differentiate the two as follows: schema matching is the process of identifying that two objects are semantically related (scope of this article) while mapping refers to the transformations between the objects.
This is an example of a lag in a Start-Start relationship. In accordance to PMBOK a lead is "the amount of time whereby a successor activity can be advanced with respect to a predecessor activity For example, on a project to construct a new office building, the landscaping could be scheduled to start prior to the scheduled punch list completion.
Most relational database designs resolve many-to-many relationships by creating an additional table that contains the PKs from both of the other entity tables – the relationship becomes an entity; the resolution table is then named appropriately and the two FKs are combined to form a PK. The migration of PKs to other tables is the second ...
For example, consider a database of electronic health records. Such a database could contain tables like the following: A doctor table with information about physicians. A patient table for medical subjects undergoing treatment. An appointment table with an entry for each hospital visit. Natural relationships exist between these entities:
A database relation (e.g. a database table) is said to meet third normal form standards if all the attributes (e.g. database columns) are functionally dependent on solely a key, except the case of functional dependency whose right hand side is a prime attribute (an attribute which is strictly included into some key).