Question

What are the benefits or disadvantages of ER diagrams? Why bother with logical design and not just create tables and columns (physical design) directly?

Answer 1

The entity relationship diagram (ER) is a flow diagram that illustrates how "things" such as men, among other systems or knowledge of objects, are related to each other. ER diagrams typically debug design or relational databases in the fields of software marketing, business information systems, research, and education. So the order of a certain ER signal or also to make use of the I'erds example to paint the rectangles, ovals and the fort, between the diamonds, is really the case, the properties and relationships. When they learn the grammatical relationships between nouns and verbs they are.

The benefits or disadvantages of ER diagrams:

The entity-in-relationship (ER) model was proposed in 1976 by Peter Bachman to unify the rational views of the network and the relational database (Coronel et al., 2017). This is the reason why the ER model of the data model in the world is seen as entities and relationships. The entity-relationship diagram in the (ero) is part of the basic information model for representing objects visually. The relationship between the ERmodel database designer and the model maps. The two tables of the copy of ease for us, it is easy to switch in a minimal relational environment. Erd uses the use of the database in the form of a concerted plan with the intention of the end.

The following are some of the advantages of the ER model:

Easy conversion for each model which allows to transform the board given ER or want to be in network, a model easily. The graphical representation allows ease of understanding. Erd in the image, and an exemplary model of agrafia, or the attributes of the various beings of reason and the same relationships between them. It helps to understand data redundancy and reduces and other problems.

uses - ER diagram

* ER database design instance of the model and relational database design in the words of reason and business rules (in the given model) and, in terms of personal technology will be implemented (by the physical data model ). The systems needed to grade the project are mostly first-time data. It is also used later to attack a particular database or databases. From the table in the database is relational, there may be in the opposition of the relationship has the power of chance, so the work that had been expressed.

The Yeast Database ER, for example, is used to analyze problems and solve existing databases or implementation. Drawing the board where you are going to reveal must be wrong.
Business information system, the diagram is used to design and analyze relational databases in business processes. Field that implies the use of the data process to the two Because for all intents and purposes, the acts of power of the composition of, and with it there is no opposition of benefit relation to a database. You can streamline processes, expose your data more easily, and improve results.

* ER diagrams of the business process itself (BPR), business support databases in the process of analyzing a database that looks and works, and in this configuration.

* The awareness of education through the educational library are today as a relationship of storage and later retrieval, it can be a valuable ER diagram in your planning data structures.

Research: Since this research focuses on structured data, and EF diagrams can play a key role in establishing databases, it is helpful to analyze the information.

Limitations ER models and diagrams;

* Relational given I only understand what the relationships show. ER describes it, it will show that it is not opposed to that of a structure relation.

There has been absolutely unstructured data - unless there is a different plane, rows or columns, and EF diagrams probably used to be limited. The same happens with semi-structured data, which is far from being useful information.

* There is an integration problem with the existing database. Using the ER model to integrate into the existing database, the challenge can be based on different architectures.