How to generate er in navicat

Navicat software is really a good thing. Today I need to analyze a database, and then I want to see the relationship between the tables, so I need to look at the relationship diagram between tables. The professional term is called ER relationship diagram.

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By default, the interface displayed by Navicat is like this of:

# The software treats the table as an object and then displays all the tables. Just through these table names, it is difficult for us to analyze the relationship between tables. Therefore, if we can display the ER relationship diagram, then we can see it clearly at a glance.

Click the "View" menu, and we see that the list is selected by default. So what we see is that the data table is displayed in list form by default. We only need to click to switch to "ER Diagram" to create an ER relationship diagram. It will take a while the first time. Detailed information can display the relevant description information of the table at the bottom, and also allows us to see the relevant information of the table better and more directly.

After the switch, the ER diagram is created. We can see that there are already differences between different tables. A good connection is established. By clicking on the connection between the two tables, we can see how the tables are related.

## It’s so simple, but I usually don’t pay attention to it, so I’d like to share it so that everyone can understand it first.

Expand knowledge

E-R diagram is also called entity-relationship diagram (Entity Relationship Diagram), which provides representation of entity types and attributes. and relational methods to describe conceptual models of the real world.

It is an effective way to describe a conceptual model of real-world relationships. It is a way of representing a conceptual relationship model. Use "rectangular frame" to represent the entity type, and write the entity name in the rectangular frame; use "elliptical frame" or rounded rectangle to represent the attributes of the entity, and use "solid line segments" to connect it with the "entity type" of the corresponding relationship;

Use "diamond box" to indicate the cause of the connection between entity types, write the contact name in the diamond box, and use "solid line segments" to connect them to the relevant entity types respectively, and mark next to "solid line segment" The type of contact (1:1, 1:n or m:n).

Components

There are the following four components in the ER diagram:

Rectangular box: represents the entity, Enter the entity name in the box.

Diamond box: indicates the contact, enter the contact name in the box.

Oval box: Represents the attributes of an entity or relationship. Record the attribute name in the box. For primary attribute names, underline the name.

Connection lines: between entities and attributes; between entities and relationships; between relationships and attributes, connect them with straight lines, and mark the type of contact on the straight lines. (For a one-to-one relationship, write 1 in each direction of the connection between the two entities; for a one-to-many relationship, write 1 on the one side and N on the many side; for many-to-many relationships, write 1 on the two entities. Write N and M in each direction of the entity connection.)

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