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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answers367
viewsMining Text with Weka
I would like to know how to create a file .arff executable to use in Weka. I remember that I am mining texts. My file is showing errors and I am unable to generate results. Below is a piece of the…
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answer1008
viewsWhat are the most common types of databases for web applications?
Some databases store objects, relational structure of tables, hierarchies, etc. What are all these types (models)? When is each application indicated (besides, of course, the developer’s…
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answers2984
viewsSurrogate Key and Natural Key
I’m studying about data Warehouse, but I was confused about the concepts of SK and NK. From what I understand, in a DW, a natural key would be a column like foregin key in the table dimension, of…
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answer2281
viewsModeling for user permissions
I think this question is more of modeling analysis actually do not know if it fits the pattern of questions discussed by meta.pt.stackoverflow.com. I need to make my system in a way that almost…
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answers766
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answer627
viewsDomain Modeling - Payment Methods
I am modeling the sales part of my system and came across the following situation. I created a register of payment methods and payment method MONEY is standard and cannot be changed, deleted, etc. I…
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answers345
viewsValues that can be entered as primary key
I have a company code of the product that is formed by two letters and 4 numbers (example: XX0000), it is advisable to use this code as primary key or create another column with code field and put…
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answers2348
viewsThe following database modeling is in my head?
I created this modeling (just an idea), so there are no null/white fields. I have not completely reviewed it. There may be fields that would remain blank. The matrix table was the Entities and…
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answers1131
viewsHow does the (anti-)EAV (Entity Attribute Value) standard work?
I would like a functional example, because I do not understand very well this dynamic relationship of creating table of types, with table of data, a dynamic relationship, that many consider…
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answer147
viewsPersisting all data as string is a problem?
Is there any problem in storing all the information of an application like string in the database? Independent of the application, SGDB, the programming language used, etc. I ask more for data…
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answers305
viewsHow to model plots when you don’t know how many there are?
Usually, when it comes to payments in instalments, comes the idea of 12 installments. Then you soon create a table with 12 fields, one for each portion. But I am faced with the situation that the…
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answer124
viewsIs it a good practice to have the same name with the column name of the bank?
Let’s say I have one input text de name="txtnome", it is a good practice to have a column of the same name as this input on my table? Being that I’m using PDO for CRUD $st…
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answers747
viewsWorking with ID limit on large volumes
I have in mind some questions about large volumes of data on MYSQL, concerning the limit of ID. I will give as an example ID guy tinyint to simplify the explanation. In the example the field tinyint…
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answers472
viewsMER - Temporal confusion of cardinality
I’m having some doubts about the temporal aspect. Example: [FUNCIONÁRIO]------<PERTENCE>------[DEPARTAMENTO] In this case it is obvious: each official belongs to one department, and each…
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answers1630
viewsModeling of a database
I created the following modeling: Would you like to know what can be improved? leading in good practice considerations for database? Explanation: In the TBLogin a person will create a login, which…
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answers1573
viewsWhat is the advantage of a 1:1 relationship?
I have a database (Mysql), and in a table I’m having about 80 columns. I am thinking of separating this information into other tables, and maintaining a 1:1 relationship. But this can impact a…
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answers1731
viewsConceptual model
I was looking at the conceptual model diagrams, I saw some that contain the attributes and entities like this: And others who only have the Entity: Which model is correct? or are both? Is it…
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answer92
viewsWhy are certain domains easier to model than others?
I have heard about certain domains, such as Guis and games, which are more "abstracted", or are already abstractions, or are "mechanisms", in short, have a distinction in relation to other domains.…
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answers727
viewsIs it bad practice to store CPF and CNPJ in the same column of the database?
In a flow that allows the registration of natural persons and legal persons I have seen the two approaches, but I’m not sure whether it is a good practice to store the two information in a column…
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answers240
viewsSpecialization and generalization in databases and application development
I have a table Livros and I know that the specialization/generalization of books are Livros de Ficção, Livros de Drama and Livros de Suspense, for example. However, in the logical model, I don’t…
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answer98
viewsDoubt when designing a database
What is the best way to design a database for a web system, for example, this system is for doctors, and every doctor has his or her schedule, patients, cashier, etc. What would be better: A single…
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answer509
viewsPolymorphism in Typescript
I am creating my application with the following structure: An abstract class Person, and inheriting from Person, the classes PessoaFisica and PessoaJuridica, And finally, a class Cliente receiving…
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answer91
viewsWhat kind of data do you use to store the date of death in a register (Datetime or string)?
I have a record of people where I need to store birth dates (DateBirth) and death (DateDeath). Knowing that the guy DateTime in C# cannot be empty and its default initial value is 01/01/0001…
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answers141
viewsDisplaying massive amount of data
From the moment we work with a very large amount of data(eg: more than 3 million records), and we need to display this data on the screen while the user uses the page, always having the best…
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answers3768
viewsUsing Redis in practice
I’m having trouble understanding in practice where to use Redis in an Ecommerce, for example. I’m reading a book but I can not understand what I have to take into account when deciding whether to…
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answer802
viewsHow to model product categories?
I am about to start the development of an e-commerce, but I am focused on the issue of modeling, especially regarding categories and subcategories of products. For example. A category can have…
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answers527
viewsStructure/Nomenclature of Tables
I am developing a permission system and I have a universe of 9 tables, which form the final permission for the user to use my systems, however, I am in doubt of how to build two of them, the…
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answer72
viewsBest way to design Classes from the database?
What is the best way to design Classes from the Database schema below: Usuario(id INTEGER PK, desc TEXT); Amigo(idA INTEGER, idB INTEGER, PK(idA,idB), FK(idA) REFERENCES Usuario(id)); This means…
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answer270
viewsCardinality in class diagram
When I diagram classes or MER, the cardinality should be defined. As an example: A doctor consults from 0 to n patients; a patient is consulted by 0 or 1 doctor. Why the 0?
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answer4985
viewsModel Entity Relationship: Ternary vs Aggregation?
Supposing I have a ternary relationship: two entities among themselves are Nxn and the third entity is weak in relation to the relationship between these two. I would like to know the difference…
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answers1701
viewsHow to represent "is-one" relationships in the logical model?
I’m creating a data model where a client entity is also a person, legal or physical. However, in the state in which it is found it will not be possible to implement it physically, because I am not…
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answer291
viewsHow to model in a correct way
I have the following table structure: First: it is right this modeling? Second: is there any way to improve? Reduce the number of tables? The system will work as follows: Each Candidate has a…
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answer102
viewsHow to model a set of 1 to 4 predetermined values
I am modeling a Mysql database where the main entities are documents. Among several other fields, these documents relate to one or more phases of a particular project. There are 4 basic values…
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answers2263
viewsModeling for comprehensive entity registration
I am creating a registration modeling in the most comprehensive way possible. Entities are Person, Natural Person, Legal Entity, Supplier and Customer Below the entity person. I add the person the…
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answer55
viewsHow to handle requirements that "mix" domain and interface?
Whenever I develop some software I try to leave the domain model without being influenced by issues relating to the other layers of the application like technologies in general and interface issues.…
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answers11076
viewsTurning factor into numeric R
Good night! I am doing a job where I import a base and after the import I create a range of values. Ex. I import the base with the read.csv dados <- read.csv(base, header=TRUE, sep=',') Put in…
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answer1998
viewsProduct modeling with various suppliers and different prices
In a stock control scenario where 1 product can be supplied by 1 or more suppliers and 1 supplier can contain 1 or more products, what to do on the following occasion: Product "X" has 2 items in…
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answer232
viewsUse of Generalization/Specialization in Data Modeling
I’ve read some articles about Generalization/Specialization in data modeling, but some questions have arisen: Is the primary key to generalization also the primary key to specializations - that is,…
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answers1851
viewsWhat is the problem of using [n]varchar(max)?
Why the practice of using [n]varchar(max) can cause problems? In my scripts whenever I don’t really know what the length of a string and to prevent problems, I have used nvarchar(max). A few days…
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answer681
viewsMutually exclusive relationship (MER)
I know there are several ways to implement this conceptual model, but I would like to know the best way (if there is one that stands out) Caption PK : Primary Key (primary key); FK : Foreign Key…
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answer201
viewsWhy do normalized schematics up to 3FN not have N:N relationships?
Explanation of the concept I believe that by definition a database schema is found in 3FN, when it is in 1FN,2FN and nay has transitive dependency. Transitive dependence is when an attribute NONKEY,…
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answers210
viewsExample of Scheme respecting the 3FN?
When studying about 3FN I came across 2 interesting examples and I wondered if when making a small change, the examples would continue to meet 3FN. Explanation about the concept of 3FN Explaining…
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answers1476
viewsIs it necessary to create a primary key with auto increment?
When I create a table that already has a field with an index unique, that will be referenced by other tables, can I leave it as primary key? Or is it good practice to create another field, with auto…
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answers299
viewsData Modeling: Integrity x Performance
In the company that I work for, there’s a data architecture that I’ve never seen before, and I’d like to know if this is common, or if it’s a new market trend. Just to mention the bank is Oracle.…
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answer167
viewsCan an employee be an individual?
Was recommended, in this question, maintain the relationship between Pessoa Física and Funcionário as generalization (Employee extends Physical Person). I do not understand why it is not in this…
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answer2433
viewsPostgresql - Partial Foreign Key of Composite Primary Key
Fala galera, I need to create a structure model where all my tables have primary key composed by id and version, so I can have multiple versions for each id. Problem: CREATE TABLE table1 { id…
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answer114
viewsProblems in the covariance structure
Hi guys All right? I’m having some problems about defining the covariance structure in R. I need to adjust the following covariance matrices: AIR GUN compSymm Uniform. As you can see in the code…
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answer134
viewsNomenclature of tables with company name and system acronym
Is there any good reason to put the company name at the beginning of the table name? In almost every company I’ve gone through, it’s an adopted convention that you have to put the name of the…
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answers100
viewsWhat are the advantages of using a database instead of a JSON file to write data?
Most systems currently use the database feature to record the most diverse types of information, even static information. This leads to the conclusion that a database brings significant…
database modeling software-engineering software-architecture language-independentasked 3 years, 3 months ago user254120 -
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answer233
viewsUML Questions for Rails System
My question is this. Rails controllers, for basic CRUD operations, require various methods that are repeated throughout the application’s controllers. I’m drawing the diagrams for a TCC application…