database design exercises and solutions

Tags: des blog http using strong dataI believe that the development experience of friends have encountered such a demand. Suppose you are developing a comment function for a news site, and readers can comment on the original text or even reply to each other.This need is not simple, mutual reply will lead to an infinite number of branches, an infinite number of ancestor-descendant relationships. This is a typical recursive relational data.For this problem, here are a few

, you need to establish database access with the connection function. You can use the javax interface, while javax is visible in the JDBC 2.0 Optional toolbox. The javax. SQL. DataSource class of JDBC 2.0 provides the connection you need. Where is the SQL statement located? It is in bean. You can use JDBCcreateStatement and PreparedStatement to create a method in bean. Turn this method into a public Vector and pass your SQL statement to this method co

I believe that the development experience of friends have encountered such a demand. Suppose you are developing a comment function for a news site, and readers can comment on the original text or even reply to each other.This need is not simple, mutual reply will lead to an infinite number of branches, an infinite number of ancestor-descendant relationships. This is a typical recursive relational data.For this problem, here are a few solutions, you ca

think if you want to implement database sharding and master-slave relationships, the number of database servers will be very large. Switching to a server in an application at any time will be a headache, is there a lot of variable names? How to find better solutions will be discussed in this article.First, database sh

operation. 2.multi-model Storage Engine ArchitectureDatabases are at the heart of many existing business systems. With the rapid development of data generation and acquisition technology, the data volume is exploding and the data structure is more and more flexible. The traditional database management system based on relational theory, facing the real arrival of big data and artificial intelligence, has met the challenge in cost, performance, expansi

Database Design-multi-value Storage The problem of storing multiple values is a common problem in database design. I think it is necessary to come up with it if many developers suffer losses. Business scenario: A business document with multiple contacts. One device maintains multiple maintenance teams. The following is

Label:I am currently working in an entrepreneurial internet company, since it is an internet company, it will be designed to either application systems or databases distributed. The following is a brief introduction to some of the database aspects of the design.database table design, according to their own business needs can be split into multiple libraries. There are order libraries, product libraries, acc

an ID. Pseudo-primary keys are a good substitute for natural keys that are too long and inconvenient to implement. For example, in a table that records all the file attributes of a file system, the file path is a good natural key, but the cost of indexing a string column can be significant. v. Solutions: Cutting Design The primary key is a constraint, not a data type. You can define any column or any numb

The problem of storing multiple values is a common problem in database design. I think it is necessary to come up with it if many developers suffer losses. Business scenario: A business document with multiple contacts. One device maintains multiple maintenance teams. The following is an example of createtableBILL (bill_idnumberprimarykey, bill_name The problem of storing multiple values is a common problem

statement optimization: If a complex statement does not have a DBA or is subject to personal capacity problems, splitting is one of the best solutions. If you are a professional DBA, ignore it. When the statement query speed is slow, you can use EXPLAIN to query the reasons for slow speed, which can help you quickly find out the cause. Other optimizations need to be optimized based on your actual situation 6. The relationship between the tables in t

Rose was first used, and EA was used for UML design, which was very convenient. EA, that is, sparx systems enterprise effecect. EA provides users with a high-performance and intuitive working interface, and works with the latest UML 2.0 specifications to create advanced software modeling solutions for desktop computer staff, Development and Application teams. This product is rich in features and highly cost

Original address: Https://www.codeproject.com/Articles/359654/important-database-designing-rules-which-I-foSpicy one?? , as if I have seen the Chinese version of this article, deteriorating, anymore ah, all kinds of plagiarism ah.The original anchor point does not know is too long, or the format has a problem, here to change.Table of Contents Introduction Rule 1:what is the nature of the application (OLTP or OLAP)? Rule 2:break your d

talk about that language all day good use of that bad, are only used for business, logical processing, if you do not use, you can write a slightly.Database design content So many, I have also participated in a number of requirements, but the scale is not small, also on the 3, 4 table design, the guy is the analysis of the need to start the physical structure of the des