commons-dbutils 是 Apache 组织提供的一个开源 JDBC工具类库,它是对JDBC的简单封装,学习成本极低,并且使用dbutils能极大简化jdbc编码的工作量,同时也不会影响程序的性能。因此dbutils成为很多不喜欢hibernate的公司的首
commons-dbutils 是 Apache 组织提供的一个开源 JDBC工具类库,它是对JDBC的简单封装,学习成本极低,并且使用dbutils能极大简化jdbc编码的工作量,同时也不会影响程序的性能。因此dbutils成为很多不喜欢hibernate的公司的首选。
/** * DbUtils的用法:利用DbUtils实现增删改查操作 * @project_name Day12 * @class_name DbUtilsDemo1 * @author Dovinya * @data 2014-8-27 下午11:07:09 * @version 1 * @notes */ /* create database day12; use day12; create table table1 ( id int primary key auto_increment, name varchar(20), salary double ); insert into table1 values(null,'zhang',234.5); insert into table1 values(null,'li',234.5); insert into table1 values(null,'wang',3242); insert into table1 values(null,'zhao',32543); insert into table1 values(null,'pan',4654); insert into table1 values(null,'he',4235); * */ public class DbUtilsDemo1 { /* * 利用DbUtils实现更改操作 */ public void update() throws SQLException { //获取数据源对象 QueryRunner runner = new QueryRunner(new ComboPooledDataSource()); runner.update("update table1 set salary =100"); } @Test public void add() throws SQLException{ //获取数据源对象 QueryRunner runner = new QueryRunner(new ComboPooledDataSource()); runner.update("insert into table1 values(1,?,?)","lisi",1000); } @Test public void delete() throws SQLException{ //获取数据源对象 QueryRunner runner = new QueryRunner(new ComboPooledDataSource()); runner.update("delete from table1 where name = 'lisi'"); } @Test public void query() throws SQLException{ //获取数据源对象 QueryRunner runner = new QueryRunner(new ComboPooledDataSource()); List<User> list = runner.query("select *from table1 where id<?", new ResultSetHandler<List<User>>(){ @Override public List<User> handle(ResultSet rs) throws SQLException { List<User> list = new ArrayList<User>(); while(rs.next()){ User user = new User(); user.setId(rs.getInt("id")); user.setName(rs.getString("name")); user.setSalary(rs.getDouble("salary")); list.add(user); } return list; } }, 5); System.out.println(list); //这里可以加断点调试观察 } }

The main difference between MySQL and SQLite is the design concept and usage scenarios: 1. MySQL is suitable for large applications and enterprise-level solutions, supporting high performance and high concurrency; 2. SQLite is suitable for mobile applications and desktop software, lightweight and easy to embed.

Indexes in MySQL are an ordered structure of one or more columns in a database table, used to speed up data retrieval. 1) Indexes improve query speed by reducing the amount of scanned data. 2) B-Tree index uses a balanced tree structure, which is suitable for range query and sorting. 3) Use CREATEINDEX statements to create indexes, such as CREATEINDEXidx_customer_idONorders(customer_id). 4) Composite indexes can optimize multi-column queries, such as CREATEINDEXidx_customer_orderONorders(customer_id,order_date). 5) Use EXPLAIN to analyze query plans and avoid

Using transactions in MySQL ensures data consistency. 1) Start the transaction through STARTTRANSACTION, and then execute SQL operations and submit it with COMMIT or ROLLBACK. 2) Use SAVEPOINT to set a save point to allow partial rollback. 3) Performance optimization suggestions include shortening transaction time, avoiding large-scale queries and using isolation levels reasonably.

Scenarios where PostgreSQL is chosen instead of MySQL include: 1) complex queries and advanced SQL functions, 2) strict data integrity and ACID compliance, 3) advanced spatial functions are required, and 4) high performance is required when processing large data sets. PostgreSQL performs well in these aspects and is suitable for projects that require complex data processing and high data integrity.

The security of MySQL database can be achieved through the following measures: 1. User permission management: Strictly control access rights through CREATEUSER and GRANT commands. 2. Encrypted transmission: Configure SSL/TLS to ensure data transmission security. 3. Database backup and recovery: Use mysqldump or mysqlpump to regularly backup data. 4. Advanced security policy: Use a firewall to restrict access and enable audit logging operations. 5. Performance optimization and best practices: Take into account both safety and performance through indexing and query optimization and regular maintenance.

How to effectively monitor MySQL performance? Use tools such as mysqladmin, SHOWGLOBALSTATUS, PerconaMonitoring and Management (PMM), and MySQL EnterpriseMonitor. 1. Use mysqladmin to view the number of connections. 2. Use SHOWGLOBALSTATUS to view the query number. 3.PMM provides detailed performance data and graphical interface. 4.MySQLEnterpriseMonitor provides rich monitoring functions and alarm mechanisms.

The difference between MySQL and SQLServer is: 1) MySQL is open source and suitable for web and embedded systems, 2) SQLServer is a commercial product of Microsoft and is suitable for enterprise-level applications. There are significant differences between the two in storage engine, performance optimization and application scenarios. When choosing, you need to consider project size and future scalability.

In enterprise-level application scenarios that require high availability, advanced security and good integration, SQLServer should be chosen instead of MySQL. 1) SQLServer provides enterprise-level features such as high availability and advanced security. 2) It is closely integrated with Microsoft ecosystems such as VisualStudio and PowerBI. 3) SQLServer performs excellent in performance optimization and supports memory-optimized tables and column storage indexes.


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