DATA NUCLEUS MYSQL 是一款用于與 MYSQL 數(shù)據(jù)庫進行交互的工具。它可簡化數(shù)據(jù)庫的管理和操作,提供方便的數(shù)據(jù)庫查詢,更易于業(yè)務開發(fā)。下面是一些有關使用 DataNucleus MySQL 的實用信息:

//創(chuàng)建數(shù)據(jù)源
public static DataSource createDataSource() {
MysqlDataSource dataSource = new MysqlDataSource();
dataSource.setServerName("localhost");
dataSource.setUser("root");
dataSource.setPassword("123456");
dataSource.setDatabaseName("test");
return dataSource;
}
//創(chuàng)建EntityManagerFactory
public static EntityManagerFactory createEMF() {
Mapprops = new HashMap<>();
props.put("javax.persistence.jdbc.driver", "com.mysql.jdbc.Driver");
props.put("javax.persistence.transactionType", "RESOURCE_LOCAL");
props.put("javax.persistence.jdbc.url", "jdbc:mysql://localhost:3306/test?characterEncoding=utf8&useSSL=false");
props.put("javax.persistence.jdbc.user", "root");
props.put("javax.persistence.jdbc.password", "123456");
EntityManagerFactory emf = Persistence.createEntityManagerFactory("test", props);
return emf;
}

在使用 DataNucleus MySQL 時,一定要先創(chuàng)建數(shù)據(jù)源和 EntityManagerFactory。同時,如果使用 JPA 進行開發(fā),還需要創(chuàng)建 persistence.xml 配置文件。

在實際應用中,我們可以利用 DataNucleus MySQL 實現(xiàn)多種操作,如創(chuàng)建表,插入數(shù)據(jù),更新、刪除數(shù)據(jù),查詢數(shù)據(jù)等。下面提供一些常見的操作代碼:

public void createTable() throws SQLException {
PreparedStatement ps = connection.prepareStatement("CREATE TABLE student (id int(11) NOT NULL AUTO_INCREMENT,name varchar(50) NOT NULL,age int(11) NOT NULL,PRIMARY KEY (id))");
ps.executeUpdate();
ps.close();
}
public void insertData() throws SQLException {
PreparedStatement ps = connection.prepareStatement("INSERT INTO student (name,age)VALUES (?,?)");
ps.setString(1, "張三");
ps.setInt(2, 20);
ps.executeUpdate();
ps.setString(1, "李四");
ps.setInt(2, 25);
ps.executeUpdate();
ps.setString(1, "王五");
ps.setInt(2, 30);
ps.executeUpdate();
ps.close();
}
public void updateData() throws SQLException {
PreparedStatement ps = connection.prepareStatement("UPDATE student SET name=? WHERE id=?");
ps.setString(1, "趙六");
ps.setInt(2, 3);
ps.executeUpdate();
ps.close();
}
public void deleteData() throws SQLException {
PreparedStatement ps = connection.prepareStatement("DELETE FROM student WHERE id=?");
ps.setInt(1, 3);
ps.executeUpdate();
ps.close();
}
public ListqueryData() {
EntityManager em = emf.createEntityManager();
Query q = em.createQuery("SELECT s FROM Student s");
Listlist = q.getResultList();
em.close();
return list;
}

通過上述代碼,我們可以輕松地實現(xiàn)與數(shù)據(jù)庫的數(shù)據(jù)交互。使用 DataNucleus MYSQL,可以大大提高開發(fā)效率,變得更加輕松和高效。