java database design

Seven major design principles:1. Single Duty principle: one class is responsible for a duty.2, the Richter replacement principle: Subclasses can extend the function of the parent class, but cannot change the original function of the parent class.3, dependency inversion principle: The high-level module should not rely on the lower layer module, both should rely on its abstraction; abstraction should not depend on detail; detail should depend on abstrac

permissions to user/role, privilegemaster "user" or "role", privilegemastervalue as UserID or roleid,privilegeaccess as "button", Privilegeaccessvalue to Btnid,privilegeoperation as "enabled"5, Privilegeoperation is set to "disabled" if you need to prohibit the permissions of individual users.If not clear can see:650) this.width=650; "src=" http://images.cnblogs.com/cnblogs_com/leoxie2011/003.png "border=" 0 "width=" 687 "height= "445" style= "border:0px;"/>

High-quality code design patterns for large. NET ERP Systems1 Cached cacheIn the system, a large number of cache design patterns are used to cache the data unchanged after the system is logged in, and not read directly from the database. Consuming some memory is much more cost-effective than reading data again from SQL Server. The basic

(because it has no descendants), but must have a foreign key (because it has a father).The design of primary key and foreign key plays an important role in the design of global database. When the global database was designed, a U.S. database

,,What is the design principle of nosql? Is there a paradigm similar to that of relational databases? I also found an article:Http://www.cnblogs.com/AllenDang/p/3507821.html! CommentsBasically, the design idea is what I mentioned above: Put the blog and comments together.This reduces the number of queries.However, a problem occurs if the user's nickname changes.Isn't every blog commented by this user going

reverse the original value and then as a parameter in the form of1 This . Getsurvey (SID); 2 s.closed =? where s.id =? " ; 3 surveydao.batchentitybyhql (HQL,!s.isclosed (), sid);　　4) The default value for the Boolean type in Java is false.　　5) The Update property of the object-oriented update operation that is the Update/saveorupdate method of the session , you cannot limit the HQL update.4. Experience Summary　　1) After performing a

Database Design Skills and database skills 1. Relationship between original documents and entities It can be a one-to-one, one-to-many, and many-to-many relationship. In general, they are a one-to-one relationship: an original document corresponds to only one entity. In special circumstances, they may be one-to-many or many-to-one relationships, that is, one ori

Link Attribute Tuples Insertion exception: when inserting data, the data cannot be inserted into the database, and the relational database cannot be operated, that is, the insertion exception. Deletion exception: when unnecessary information in a link is deleted, the information that should not be deleted is also deleted, that is, the deletion exception. Update exception: when updating a

Before designing a database1. Test the existing environmentWhen designing a new database, you should not only carefully study the business needs, but also examine the existing system. Most DatabasesProjects are not built from scratch. Normally, there will always be existing systems within the Organization to meet specific needs (there may be no realAutomatically calculated ). Obviously, the existing system is not perfect, otherwise you do not have to

button on the page 3, the permission can be "visible", can be "read-only" or "Available " ( such as a button can be clicked ) is actually the WHO, what, how problem So the six tables mentioned above can actually design a table: IV, example description Here is an example of a design description. "User, role on page is permission to use" Detailed design: 1,

department 2, the domain can be a module, can be a page, or it can be a button on the page 3, the permission can be "visible", can be "read-only" or "Available " ( such as a button can be clicked ) is actually the WHO, what, how problem So the six tables mentioned above can actually design a table: IV, example description Here is an example of a design description. "User, role on page is permission t

business processing tables, in addition to adding the generated AutoNumber IDs (typically used as primary keys), the time CreateDate (creation time) of the record created, the creator of the record Creatby (note here, no ui_ ID (User Information table User_info primary key ui_id), because there are modified people), finally modified the person Lasteditby, the last modification time lasteditdate. (these can be used directly with Chinese characters, without coding, to improve the efficiency of th

In recent work, we need to design a complete system, including B/S web services and databases, and the C/S structure of the application layer private communication protocol.ProgramModule, involving interaction with external databases and external modules. Because I am really a little bit of a design, and I am not familiar with database and web, after I have

A brief introduction of database design Method Manual test method Design quality is directly related to the experience and level of the design staff Lack of scientific theory and engineering method support, the quality of the project is difficult to guarantee The database ru

My first python web development framework (4) -- database structure design and creation, and python Structure Design After finishing the front-end html design, Tom immediately began to design the database structure. 　　 Before he s

If the database design is likened to Sherlock Holmes, according to a variety of conditions, restrictions, rules, the ladder of Cocoon, looking for the mutual links, step-by-step in-depth case of the middle, the final settlement of the case. But the first need to solve the case, then for the database design to use a lon

Tags: performance selection memcached style HTTP under Good information fetch numberWhen you design a database, a field belongs to one table, but it appears in the other or more tables at the same time, and is exactly the same as the meaning of the table it belongs to, then this field is a redundant field. --These are the definitions I gave myself. Is the existence of redundant fields good or bad ( Redunda

3 efficient Tags tag system database design solutions, tags design solutions Background Currently, mainstream blog systems and CMS all have a TAG Tag system, which not only enhances the structure of content links, but also allows articles to be distinguished by tags. Compared with the traditional Keyword mode, this Tag mode can independently

If these two conditions are met, it can be explained that the standard of the database is still relatively high. Of course, this is a two-generalities indicator. In order to meet the requirements of database design normalization, the following five requirements are generally required. Request One: Nullable columns should be avoided in the table. Although emp

Basic steps of database design According to the standard design method, considering the whole process of database and its application system development, the database design is divided into the following 6 stages 1. Demand Analys