Most voted "modeling" questions
Modeling means creating a model that explains the working and behavior characteristics of a software from which it will be created, facilitating its understanding and its design, through the main features that will avoid programming errors, design and operation.
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answers3205
viewsModeling database of a system of friends
Hello, I am developing an application where there will be an option to add friends,is very simple, it is not social network, but have to add friend. I have the user table. What tables and…
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answers1023
viewsDatabase modeling problem
I created a system that has control of sales (id, id_vendedor, produto), salesman (id, nome, id_equipe) and team (id, nome) in a company. Example: "John has id: 1 and belongs to the team: Blue; in…
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answer2019
viewsCould you add a UNIQUE field that accepts nulls?
I can create a field that accepts nulls and say it is unique? This table of mine, the CRM indicates that he is a doctor and not a normal person, he has to be unique, but has to allow nulls. This…
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answers2291
viewsStoring measure drive in Mysql table
In one of my forms it will be necessary to collect the height of the user in meters. However, this form can be in English or in Portuguese. If you are in English this height will be in feet (Feet).…
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answer1367
viewsConvert MER (Entity Relationship Model) diagram to VB.NET or C#
I developed the diagram of the tables of the layout of the XML of Nfe, are 58 tables with its relationships. I would like to generate the classes automatically from the diagram or it can be through…
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answer189
viewsIs there a simple method to test a logical data model?
It’s been a while since I learned the Entity-Relationship Model, and my teacher taught me that after the logical model is ready it’s always interesting to test the model to check for possible…
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answer919
viewsModeling Categories and Subcategories
I am modeling a database related to e-commerce and I have a question in the modeling of the tables of categories and subcategories of products. At first I created two tables one of Categoria and…
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answer130
viewsWhat kind of system modeling is that?
I have seen in several places companies that develop commercial systems (usually in DELPHI) and these respective systems are modeled so that they stay with an application "server" in which I believe…
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answers66
viewsStoring data that can be accessed outside the database itself, goes against the 1st Normal Form?
For example, I have an invoice, which I can consult in another database (but not of my property), an example would be Pagseguro. I store only the invoice identification number to be able to consult.…
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answer398
viewsRelationship 0.. 1 in practice
Having the following tables: request address table Orders can be made at the pizzeria, that is, for a table. It can be a delivery(address) or it can be a request for travel, where it does not belong…
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answer229
viewsIpv4 and/or IPV6 record in the database
The Internet works through protocols like Ipv4 and Ipv6, possessing 32 bits and 128bits, which are numerical combinations that establish connections between computers. I have a device table,…
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answer689
viewsAcademic ER "system" modeling
Guys, can someone help me? I’m doing a database job where I have to do an academic "system", I developed this photo ER, I have doubts of type: How do I make the teacher store the notes and…
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answer174
viewsGenerate number using Identity
Is it possible to generate a number before writing the record to the database? Use field identity do SQL Server 2014. Work with Delphi Berlin.
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answer1598
viewsModeling for shared address table
I have 3 entities: Ponto, Solicitante and Serviço. Each one has its own address, but it is possible that the 3 have the same address. If an entity changes its address, it shall not change the…
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answer842
viewsBest way to structure history table with large amount of data
Functional requirement I own devices. Each device roughly has its unique identifier, an IP address, and a type. I have a routine of pings for every device that has an ip address. This routine is…
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answer492
viewsCreating Models that derive Identityuser or use the Aspnetusers table
I am developing management software for my gym. I have Students, Teachers and system users. I installed the Identity. I created a model calling for Aluno who inherits from the IdentityUser public…
c# asp.net-mvc entity-framework modeling asp.net-identityasked 8 years, 3 months ago Dorathoto 7,426 -
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answer1111
viewsModeling database table
I am creating a database that stores an electronic invoice - "Nfe" received. Within the items of a tax note are always linked taxes. Table example tblProdNFe_Entrada with the table…
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answer139
viewsSpeed in crossing tables - R
good night! I cross two bases in Rstudio, using the merge, however, I would like to know if using another crossover medium (ex:left_join), I get faster, because my tables reach 8 million lines.…
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answers855
viewsModeling launches using customers and suppliers
Contextualization: Initially I am developing a launch module (accounts payable and receivable). Every release must be related to a supplier or customer. As I wish to model both customer and supplier…
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answers16608
viewsWhat is the difference between MER (Relationship Entity Model) and DER (Relationship Entity Diagram)?
What is the difference between an MER diagram and an ERI diagram, with examples.
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answer82
viewsIs it mandatory to list tables in a database?
I have a slight knowledge of the database and I know how to use it JOINfor certain SELECTs. I am mounting a simple DB where I have certainty absolute that a table has no relations with others. Is it…
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answer438
viewsStoring multiple values of an Enum in the database
I wish I could save several options of an Enum (day of the week) something like 1,3,5 (Monday, Wednesday, Friday) As modeling described here. I created a model public class Horario { [Key] public…
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answers150
viewsDatabase modeling, when it is possible to denormalize
I’m modeling a database (MSSQL) and a question has arisen. In every business rule of the clients the data is visualized vertically ex: Product, Original Price, Concurrent Price 01, Concurrent Price…
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answers2246
viewsDoubt in class diagram
Good afternoon. Follow the question about class diagram with the diagram I was able to do. Describe the class diagram for a simple room reservation and occupancy system for a hotel. The system must…
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answers88
viewsGood practices for data of product characteristics that may be different for each item
I own several products and each one has its own characteristics, some have weight, some do not, some have extra fee and others do not, etc. Is it good practice to create a new table of product…
modeling software-engineering software-architecture dddasked 5 years, 7 months ago Danilo Tiago Thai Santos 409 -
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answers334
viewsIs "inheritance" table a bad practice in this case?
In my database I need to store employees, customers and suppliers. Since all these share data in common, but not all the data, I decided to create a table pessoas with the columns in common: id //…
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answers106
viewsHow to implement an interface to secure a specific contract?
Need to get an interface to implement a list of a certain type: public class ITrade<T> { public int date { get; set; } public double price { get; set; } public double amount { get; set; }…
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answers721
viewsUML - Use Case
Hello, I am as a doubt about the elaboration of a use case, and I would like to know if I can apply Generalization/ Specification in cases of uses or is only in the actors? Example 1 (No…
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answer114
viewsEntities classes
I am developing a sales project to which I will have registered a funcionário which may also be a vendedor, I’m gonna have a cliente which may be a pessoa física or pessoa jurídica, fornecedores…
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answers148
viewsHow do you model a role in object orientation?
How one normally models a role (role) object-oriented? It is by means of a composition, correct? For example, to model that a Pessoa executes the paper of a Cliente or Fornecedor, it is modeled that…
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answer155
viewsUse multi-tenancy model or other types?
I am working on several systems for a single company. In some cases, the systems must integrate and in others not. For example, user access control must communicate with all other systems, since…
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answers245
viewsDoubts in the modeling of the Database
Guys, I have the Product, Ingredient and Sale table. The product contains several ingredients, e.g.: Suppose that the product is a mixture, it contains 1 bread and 2 Ingredient cheeses, this…
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answer779
viewsDatabase normalization in HR system
I am developing an HR application, in it I will have many forms in HTML that may or may not be very extensive, the employee table for example has 45 fields, some fields like company, function and…
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answer3140
viewsMost likely due to a circular import (How to Resolve)
Good night. I’m new in Django/Python, I’m developing a system where I have a circular relationship, I have the class person and the company, where a person belongs to a company and a company is a…
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answers75
viewsStore data in DB vertically or horizontally?
I recently posted a question about number of fields in a table here: Number of Columns X performance in tables Now I am curious about the standardization in the creation of the table below, I have…
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answer2703
viewsWhat are the recommended values for Mysql database (id, user, password and email)?
I created a table user with the following values: Tipo = `MyISAM` ID = `int, PRIMARY, AI`; Usuário = `varchar, 16`; Senha = `varchar, 16`; Email = `varchar, 100`; Are these values recommended?…
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answer649
viewsHow to Import a . er1 File into CA Data Modeling
I need to import an . er1 file from an older version of Erwin in CA Data Modeling (Community Edition). This is possible ? I tried to open direct and the options of "Import" unsuccessfully. Grateful…
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answer2262
viewsDER for student, discipline and course
A student can only have one course. A course has several disciplines. The student can take several courses of the course. My only doubt is what it would look like on the DER? Would really look that…
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answers79
viewsAdd a login field to an existing user table
What would be the best way to add a field of login in an existing database table with about 10,000 users. I am currently using Mysql and would like to remodel the user table, at the moment the table…
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answer372
viewsProblems with RBAC permissions modeling
I’m developing a system where your user permissions will be based on the RBAC model, a user could be in several permissions rules that would give or not privileges to the system, when registering a…
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answer228
viewsDifferentiate product from ingredient
I am trying to make a system for sale of açaí. In an açaí can add many ingredients like paçoca, milk powder, fruit and etc... Açaí can also be sold in 250ml, 500ml and 750ml pots. Depending on which…
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answer366
viewsTables with columns always null
Is it considered wrong to create tables with mutually exclusive columns? For example, I have tables Texto, Trecho and Linhas, whereas Texto and Trecho has many Linhas, the table Linha is holding the…
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answer271
viewsDatabase with extra headers
Does anyone know any database in which, in addition to the traditional architecture (rows and columns), we could create and manipulate FIELDS, which would be available for reading and writing and…
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answers97
viewsReverse process modeling
Always, or almost, if the Conceptual ER is made and then we model the Logical ER, in the BR Modelo It is possible to create the Conceptual ER and generate the Logical ER automatically, but when…
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answers145
viewsModeling Database
Specifying the tables I’m doubtful are, in my case, a work of a company for the college, the tables: Input and Diagnosis, in which the input is when someone brings some equipment, and then is made…
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answers302
viewsTool for data modeling
Is there any tool for data modeling free in which I can make a Reverse Engineering of a Sql Server database ( express 2012) other than the Dbdesegner Fork ?…
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answer110
viewsModel comments
I’m creating a comment structure similar to Mercadolivre, how do I make the modeling contemplate and ensure that: NOTE: I’m calling comments question and answer since this is basically how the Free…
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answer1123
viewsData Management System Log System
I am developing a data management system in PHP Laravel 5. In this system I want to put a Logs. 1 - Laravel has some library that facilitates this system ? 2 - If Laravel doesn’t have the best way…
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answers2032
viewsHow to relate tables in Mysql to more than one entity?
How can I relate a table(entity) to more than one entity in the Mysql database? following the following example... I have the tables: fornecedores, clientes and telefones. The fornecedores, may have…
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answer880
viewsDatabase for the Poll
I’m doing a questionnaire system and I’m having a hard time modeling the database. I need my system to be "smart" enough to ask different questions according to the answers. For example, my first…