Most voted "cardinality" questions
In relational databases the records of two tables may have one-to-one, one-to-many or many-to-many relations. This relation is called cardinality and is a fundamental aspect of data modeling.
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14
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answer1047
viewsWhat is the cardinality between a request and the services included in it?
I have the class Solicitacao and the class Servicos. After insertion in the database I intend to recover in a query all the services associated with that request. For example, on a screen I insert…
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8
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answer564
viewsCardinality of the index does not update
I am creating a program that connects to a Mysql database online, and when starting it it creates a table with an index if it does not exist. To check if everything is ok I am analyzing the database…
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answers1800
viewsIn which table is the foreign key in a ratio 1 to 1?
In an SQL relationship of two tables 1 to 1, there is some rule that defines which table the foreign key will be in?
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4
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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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2
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answers3569
viewsHow to find relationship and cardinality in Mysql?
The image below shows a relationship between two tables created from Mysql Workbench. What I need to know is how I can find this information inside the database. I need to know exactly what kind of…
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2
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answers239
viewsCreation of tables with cardinality 1 : N
I have two tables, PRODUTOS and INSUMOS. To create a product I need several inputs, I would like to know how I should proceed with this relationship in Mysql. I must create a table called COMPOSICAO…
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1
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answer1512
viewsRelationship (0.1) in mysql Workbench
I’m doing a project and I started by modeling the bank was all right up to the point of users that I got confused. Rules: general admin (access to all), admin company(access to all company events)…
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1
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answer559
viewsCardinality in Database - Relationship One to ONE
I’m studying databases, and at the moment beyond bank definitions, type of models I’m seeing Cardinality! I’m having doubts in this exercise below: My doubts are as follows How I identify the origem…
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answers1511
viewsMinimum Cardinality and Maximum Cardinality in Database
Good Afternoon! I’m trying to understand about Cardinalidade Minima and Cardinalidade Máxima between different entities! What I know so far is : A Cardinalidade Minima can be a Atributo Opcional(0)…
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answer27
viewsDoubt with relation of tables - Modeling
Next guys, to with 3 tables here, I’m in doubt how to relate them. I am studying relationship tables here... This project is a stock system, and has no intention, except to practice and study! My…