java database design

Label:The establishment of a master-slave database is generally based on the following three considerations:1. Disaster recovery: The repository is offsite, the main library does not exist, the repository can be immediately taken over, no restoration time;2. Load balancing: The main library to do additions and deletions, prepare the library to do queries, so many query services do not occupy the main library resources;3. Data centralization and distri

Design method of database table structure When we design a database storage mode, we need to analyze the data pattern carefully and not put all the data together in a single brain. In that case, the availability of the system, efficiency, scalability will have a serious impact. Of course, the system you designed is ve

inconvenient to ask the administrator to assign the system operation permissions to the employees. Therefore, the concept of "group" is put forward in the system, the people who have the same rights are programmed into the same group, and then the group is assigned permissions. The Rights management system should be extensible . It should be added to any system with rights management capabilities. Just as a component can be reused continuously, rather than developing a set of management system

[DAO] simple document of billing system database design, dao Billing System DatabaseDatabase Design Documents Database Design Documents, SQL statements for table creation. 1) account Id number (9) PK account ID Login_name varchar2 (20) not null user self-service Username Log

Enumeration, a data type (as opposed to the C # language, of course, java,php), and the use of enumerations in projects have some of the following advantages.First: The definition is intuitive, easy to use,Second: Easy to maintain and extend (actually intuitive)For the display of data of enumerated types, it is generally defined within the program such an enumeration, and then through the program to get the enumeration corresponding to theKey name, or

The process of database design Database technology is the most effective means of information resource management. Database design refers to a given application environment, constructs the best database model, establishes the

Label:In terms of WinForm, based on the different business, we can use the efficiency of the tool, quickly do a lot of different business systems, a defect management system, want to put the unit Test business specifications, statistics and analysis of each version of the defect information, this chapter to collate these database design and interface design relat

Java design mode 6 -- Adapter mode and design mode 6 -- URL: http://www.cnblogs.com/archimedes/p/java-adapter-pattern.html. Adapter mode (alias: Package) Converts an interface of a class to another interface that the customer wants. The Adapter mode allows the classes that cannot work together due to incompatibility of

Database Design-semi-structured storage and database structured storage Business scenario: the user fills in some documents, reports them, and approves them. There are several fields in the document that need statistics, and the business is not complicated. In a seemingly simple scenario, when the developer came up with the PDM

Abstract This article mainly analyzes the ORACLE system structure and working mechanism from four different levels of Adjustment Analysis in the ORACLE environment of a large database, the optimization and adjustment schemes for ORACLE databases are summarized in nine different aspects.Key words: ORACLE database environment Adjustment Optimization Design SchemeTh

In the design of a relational database, it is usually necessary to specify a primary key for each table, and a primary key is a property or group of attributes that uniquely identifies a row of records in a table, and a table can have only one primary key, but may have multiple candidate indexes. Because a primary key can uniquely identify a row of records, you can ensure that no errors occur when you perfo

Classification of plant design and design patterns: The factory model is divided into three categories in Java and mode:1) Simple Factory mode (simply Factory): not conducive to the production of products;2) Factory method mode (Factory): Also known as the polymorphism plant;3) Abstract Factory mode (abstract Factory): Also known as the toolbox, producing product

Design paradigm of relational databases and database design paradigm 1. 1NF)The first paradigm is the basis of the second and third paradigm and the most basic paradigm. databases that do not meet the first paradigm are not relational databases.Guiding principles of the first paradigm:1) Each attribute of a Data Group can only contain one value.2) Each array in

Label:To build a Web rights configuration system, you need the following five data tables: People table, grouping table, page table, table of contents, Operation permission table. The IDs used in each data table are the identity of the self-increment 1, and each data table is defined as follows:1.1 Personnel table (Operatorinfo)1.2 Grouping table (Operatorgroup)1.3 Page Table (PageInfo)1.4 Table of Contents (catalog)1.5 Permissions table (rightlist)1.6 Mapping relationshipsUser tables can be map

The entity Association design language of nbearv3. The new syntax can more clearly express all common object associations. The new implementation version implements both database integrity constraints detection and automatic cascade updates. All nbearv3 tutorials have been updated to reflect the latest changes. Online tutorial directory:Nbearv3 Chinese tutorial directory The latest version of nbearv3.2

, etc.malling_goods_category: Classification, classification number, name, higher class number, etc.Malling_goods_comment: A review of a product, a user who has purchased a productbefore you can comment on this product .malling_orders: Order, order number, owner, Total Price, payment method, etc.Malling_orders_item: Order item, an order can have more than one order item, order number, owner, product ID, item quantity, total price, commodity PriceLog RelatedMalling_op_log: Operations logs, such a

Byte[1024];int len= 0;while ((Len=input.read (b))!=-1) {output.write (B,0,len);} Output.close (); Input.close ();} catch (IOException e) {e.printstacktrace ();}}}Test class:Package Behavior _ template method mode; public class Gettimemain {public static void main (string[] args) throws Exception {//gettime gtime = NE W GetTime ();//system.out.println (Gtime.gettime () + "millisecond")///For abstract programming GetTime GT = new Forgettime (); System.out.println (Gt.gettime () + "MS");//re-assig

patterns, and the book has been recognized as a cornerstone in the field of design patterns.Some basic principles of object-oriented1. For abstract principlesWhen designing a class, do not let the class target a specific class, but instead target an abstract class or interface.For example: Define a cylinder with a triangular bottom face2. Open-Close principleThe design should be open to extensions and clos

In general, two aspects can be used to determine whether the database design of the comparison specification. One is to see whether there is a large number of narrow tables, and the second is that the number of wide tables is small enough. If these two conditions are met, it can be explained that the standard of the database is still relatively high. Of course, t

possible.2.4 Design2.4.1 ParadigmIf there is no performance necessary reason, should use the relational database theory, achieves the high paradigm, avoids the data redundancy, but if in the data quantity and the performance does not have the special request, considers the realization convenience to have the appropriate data redundancy, But basically to reach 3NF. If necessary, avoid the practice of storing multiple flags in a field. A value of 11101