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Er-designer provides a number of tools and features to help you create, reorganize, and customize ER diagrams, and it can also export ER diagrams in JPEG format. In this tutorial, you will learn to:
Entity diagram (ERD) retrieved from the database in reverse
Using table data in an ER diagram
Routing Table relationships
Lookup table
Export
explain
Entity Relationship diagram: denoted e-R diagram refers to the basic structure of data based on the three basic concepts of entity, relation and attribute, thus describing the conceptual model of static data structure. The e-R d
7.3 Persistent Object relationship diagram
Persistent order involves operations on multiple entities. Although only order and its details are updated, the products of order's customer and details will also be involved as read-only data. Because multiple entities are involved, we need to talk about the entity graph or the object graph ).
7.3.1 object
The original purpose of the translation and why choose the Entity Framework 6 Recipes to learn, please see the beginning of this series2-10 Table per Hierarchy inheritance modelingProblemYou have a database table that has a type or identification column. It can tell what the data in the row represents in your application. You want to model using table per hierarchy (TPH) inheritance mapping.Solution SolutionsLet's say you have a 2-20 of the table (the
need to create an intermediate table that stores the primary key ID of two tables respectively)Key indicates the corresponding column,The Userdetails attribute is in the role class(4) Also many to many, with the same(5) The Department is self-related, the superior department is many to one, the subordinate department is a pair of many(6) Permissions are self-correlating, same as aboveThree: test, create a table when creating a sessionfactory, write a junit test execution(1) The Discovery table
bloguser can have multiple blogsite).
You may be wondering. Clearly is one-way one-to-one entity relations, here how to make a one-to-many relationship.
If there is such doubt, is normal phenomenon, I wrote the article from last July began to doubt, has been puzzled until now, write an article just a little understand.
Notice what "one-way one-on-one" is. is an entity
1. Visualizing entity relationships with ER graphsMyEclipse Er-designer helps you visually manage relational databases, from the design lifecycle through to the implementation and maintenance of this series of processes. At the same time MyEclipse Er-designer also provides a visual model of the existing database. Because of the entity-relationship (ER) model of E
Interpretation of the object relationship diagram: A Brief E-R diagram refers to the three basic concepts of the object, relationship, attribute to summarize the basic structure of data, so as to describe the concept of static data structure. A E-R diagram is an
Tags: databaseI've heard of it before, in the project. Powerdesinger , but has never been used, this time through the foundation of the elective module finally has the opportunity to pass Powerdesinger of the CDM model to create a database. Powerdesinger There are several data models in the system, namely: M----Model,
Conceptual Data Model ( CDM ) Conceptual Diagram Model
logical Data Model ( LDM )
Physical D
In the study of SPSS statistical analysis, EA Drawing entity Relationship diagram, PowerDesigner drawing Database Model diagram, and so on, have been unable to find a good example. Because the structure of the project used in the actual work belongs to the company's commercial confidential content, and its structure is
relationship between a class and a class, and an inheritance relationship between an interface and an interface. Figure h1.1.6 Implementation (realization): Hollow arrow and dashed line representationThe example ( figure I) relationship specifies a contract between two entities. In other words, one entity defines one
From Acacia (one-to-one), to mutual affection (two-to-one), and into the marriage hall, the next step is to have children, men are upgraded to fathers, if many children are given birth, the relationship between the father and the child is "one-to-many ".
A father has multiple children, and a child belongs to only one father.
Let's take a blog as an example. The scenario is as follows:
One blog (blogsite) has multipleArticle(Blogpost), an article
there is no loop in the instance diagram. In other words, it can only be a one-way relationship.
Figure F
Synthesis (composition)
Synthesis ( fig. G) is a special form of aggregation, implying "local" within the "whole" life-cycle responsibility. Synthesis is also not shared. Therefore, while the part does not necessarily have to be destroyed with the destruction of the whole, the whole is either responsib
become a key part of the website architecture and the hub of website operation. To facilitate and easily manage large volumes of data, user accounts, news, content, and statistics can all be stored in the relational database management system (RDBMS ).
Using graphs to manage data models is efficient and convenient. For RDBMS, an image describing a data model is usually called an entity relationship
database table or extract information from the database. For most websites, database tables quickly become a key part of the website architecture and the hub of website operation. To facilitate and easily manage large volumes of data, user accounts, news, content, and statistics can all be stored in the Relational Database Management System (RDBMS ).Using graphs to manage data models is efficient and convenient. For RDBMS, an image describing a data model is usually called an
Hibernate entity Mapping template1, write a comment? format:? attribute, which is the expression of this object with? Of Relationship. Example: "department attribute, this object and department's many-to-one" 2, copy Template:
Many-to-one
one-to-many ( set
Many-to-many(
To the users of Photoshop software for detailed analysis to share the GIF animated diagram embedded in the mobile phone template of the later tutorial.
Tutorial Sharing:
Yesterday, a design sister asked me this question, since it is a sister then I will spend five minutes to teach you embed GIF to template.
1. First use hype or
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