Oracle使用JDBC进行增删改查表是否存在

数据库和表

table USERS
(
  USERNAME VARCHAR2(20) not null,
  PASSWORD VARCHAR2(20)
)
alter table USERS
  add constraint U_PK primary key (USERNAME)

//检查表是否存在
public boolean validateTableExist(String tableName){
  int result = 0;
  String sql = "SELECT COUNT(*) FROM USER_OBJECTS WHERE OBJECT_NAME = UPPER('"+tableName+"')";
  Connection conn = this.getSession().connection();
  Statement st = null;
  ResultSet rs = null;
  try{
   st = conn.createStatement();
   rs = st.executeQuery(sql);
   rs.next();
   result = rs.getInt(1);
  }catch(Exception e){
   e.printStackTrace();
  }finally{
   this.util.closeAll(rs, st, conn);
  }
  return result==0?false:true;
 }

JDBC的完整方法,CloseAll方法就不给你写了.如果表存在就返回True,不存在返回False,可以直接用在你的IF判断中:
if(validateTableExist(tname)){
  String sql1="insert into "+tname+" values(?,?,?,?,?,?)";
  ....................
}

/**
* JdbcExample.java
*
* Provider: CoderDream's Studio
*
* History
* Date(DD/MM/YYYY) Author Description
* ----------------------------------------------------------------------------
* Apr 14, 2008 CoderDream Created
*/

package com.coderdream.jdbc.oracle;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

/**
* @author XL
*
*/
public class JdbcExample {

private static Connection getConn() {
        String driver = "oracle.jdbc.driver.OracleDriver";
        String url = "jdbc:oracle:thin:@10.5.15.117:1521:csi";
        String username = "scott";
        String password = "tiger";
        Connection conn = null;
        try {
            Class.forName(driver);
            // new oracle.jdbc.driver.OracleDriver();
            conn = DriverManager.getConnection(url, username, password);
        }
        catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        catch (SQLException e) {
            e.printStackTrace();
        }

return conn;
}

private static int insert(String username, String password) {
        Connection conn = getConn();
        int i = 0;
        String sql = "insert into users (username,password) values(?,?)";
        PreparedStatement pstmt;
        try {
            pstmt = conn.prepareStatement(sql);
            // Statement stat = conn.createStatement();
            pstmt.setString(1, username);
            pstmt.setString(2, password);
            i = pstmt.executeUpdate();
            System.out.println("resutl: " + i);

pstmt.close();
            conn.close();
        }
        catch (SQLException e) {
            e.printStackTrace();
        }

return i;
}

private static void query() {
        Connection conn = getConn();
        String sql = "select * from users";
        PreparedStatement pstmt;
        try {
            pstmt = conn.prepareStatement(sql);
            ResultSet rs = pstmt.executeQuery();
            while (rs.next()) {
                System.out.println("name: " + rs.getString("username")
                        + " \tpassword: " + rs.getString("password"));
            }

rs.close();
            pstmt.close();
            conn.close();
        }
        catch (SQLException e) {
            e.printStackTrace();
        }

}

private static int update(String oldName, String newPass) {
        Connection conn = getConn();
        int i = 0;
        String sql = "update users set password='" + newPass
                + "' where username='" + oldName + "'";
        PreparedStatement pstmt;
        try {
            pstmt = conn.prepareStatement(sql);

i = pstmt.executeUpdate();
System.out.println("resutl: " + i);

pstmt.close();
            conn.close();
        }
        catch (SQLException e) {
            e.printStackTrace();
        }

return i;
    }

    private static int delete(String username) {
        Connection conn = getConn();
        int i = 0;
        String sql = "delete users where username='" + username + "'";
        PreparedStatement pstmt;
        try {
            pstmt = conn.prepareStatement(sql);

i = pstmt.executeUpdate();
System.out.println("resutl: " + i);

pstmt.close();
            conn.close();
        }
        catch (SQLException e) {
            e.printStackTrace();
        }

return i;
}

/**
     * @param args
     */
    public static void main(String[] args) {
        insert("CDE", "123");
        insert("CoderDream", "456");
        query();
        update("CoderDream", "456");
        query();
        delete("CoderDream");
        query();
    }
}

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Oracle使用JDBC进行增删改查表是否存在

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Oracle使用JDBC进行增删改查 表是否存在

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Oracle使用JDBC进行增删改查表是否存在