2 回答

TA貢獻(xiàn)2080條經(jīng)驗(yàn) 獲得超4個(gè)贊
package basic;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class JDBC {
public void findAll() {
try {
// 獲得數(shù)據(jù)庫驅(qū)動(dòng)
//由于長時(shí)間不寫,驅(qū)動(dòng)名和URL都忘記了,不知道對不對,你應(yīng)該知道的,自己改一下的哈
String url = "jdbc:oracle:thin:@localhost:1521:XE";
String userName = "system";
String password = "system";
Class.forName("oracle.jdbc.driver.OracleDriver");
// 創(chuàng)建連接
Connection conn = DriverManager.getConnection(url, userName,
password);
// 新建發(fā)送sql語句的對象
Statement st = conn.createStatement();
// 執(zhí)行sql
String sql = "select * from users";
ResultSet rs = st.executeQuery(sql);
// 處理結(jié)果
while(rs.next()){
//這個(gè)地方就是給你的封裝類屬性賦值
System.out.println("UserName:"+rs.getString(0));
}
// 關(guān)閉連接
rs.close();
st.close();
conn.close();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void delete(){
try {
//步驟還是那六個(gè)步驟,前邊的兩步是一樣的
String url = "jdbc:oracle:thin:@localhost:1521:XE";
String userName = "system";
String password = "system";
Class.forName("oracle.jdbc.driver.OracleDriver");
Connection conn = DriverManager.getConnection(url,userName,password);
//這里的發(fā)送sql語句的對象是PreparedStatement,成為預(yù)處理sql對象,因?yàn)榘礂l件刪除是需要不定值的
String sql = "delete from users where id = ?";
PreparedStatement ps = conn.prepareStatement(sql);
ps.setInt(0, 1);
int row = ps.executeUpdate();
if(row!=0){
System.out.println("刪除成功!");
}
// 關(guān)閉連接
rs.close();
st.close();
conn.close();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

TA貢獻(xiàn)1798條經(jīng)驗(yàn) 獲得超3個(gè)贊
NoSQL數(shù)據(jù)庫有很多種,實(shí)現(xiàn)方式差別很大。有接近SQL查詢方式的,也有純粹的鍵值對查詢。
對于K-V型數(shù)據(jù)庫,比較典型的是Redis,系統(tǒng)提供了get、set之類的命令用于增刪改查。關(guān)鍵是鍵值對的鍵和值怎么設(shè)計(jì)
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