sqlite数据的增删改查------Java代码

来源：互联网发布：有招聘淘宝主播的吗编辑：程序博客网时间：2024/05/01 22:39

方法一

import com.example.day014_sqliteopenhelper.db.MySqliteHelper;

import android.os.Bundle;
import android.app.Activity;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.view.Menu;
import android.view.View;

public class MainActivity extends Activity {

   //将数据库的帮助类声明出来
   private MySqliteHelper helper;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        helper = new MySqliteHelper(MainActivity.this);

    }
    /**
     * helper.getWritableDatabase()
     *
     * helper.getReadableDatabase()
     *
     * 磁盘没满的时候   他们两个是一样都可以读写
     * 磁盘满的时候       getWritableDatabase()打开失败
     *                getReadableDatabase()
     * @param v
     */
    public void onClick(View v){
       switch (v.getId()) {
       case R.id.btn_create://创建数据库
           SQLiteDatabase db = helper.getWritableDatabase();
           db.close();
           break;
       case R.id.btn_insert://创建数据库
           //首先获取数据库
           SQLiteDatabase db1 = helper.getWritableDatabase();

           String sql_insert = "insert into person values(1,'zhangsan',23)";
           String sql_insert1 = "insert into person values(2,'lisi',24)";
           String sql_insert2 = "insert into person values(3,'wangwu',25)";

           for(int i=4;i<20;i++){
               String sql_insert3 = "insert into person values("+i+",'zhangsan"+i+"',25)";
               db1.execSQL(sql_insert3);
           }
           //执行
           db1.execSQL(sql_insert);
           db1.execSQL(sql_insert1);
           db1.execSQL(sql_insert2);

           db1.close();
           break;
       case R.id.btn_query:
           //首先获取数据库
           SQLiteDatabase db2 = helper.getWritableDatabase();

           String sql_query = "select * from person";
           //指定的查询语句 cursor游标
           Cursor cursor = db2.rawQuery(sql_query, null);
           //判断下一条语句是否存在
           while(cursor.moveToNext()){
//               int id = cursor.getInt(0);
//               String name = cursor.getString(1);
//               int age = cursor.getInt(2);
               int id = cursor.getInt(cursor.getColumnIndex("_id"));
               String name = cursor.getString(cursor.getColumnIndex("name"));
               int age = cursor.getInt(cursor.getColumnIndex("age"));
               System.out.println("==id==:"+id+"==name=="+name+"==age=="+age);
           }
           db2.close();
           break;
       case R.id.btn_update:
           //首先获取数据库
           SQLiteDatabase db3 = helper.getWritableDatabase();
           String sql_update = "update person set name 'hah' where _id = 1";
           db3.execSQL(sql_update);
           db3.close();
           break;
       case R.id.btn_delete:
           //首先获取数据库
           SQLiteDatabase db4 = helper.getWritableDatabase();
           String sql_delete = "delete from person where _id = 2";
           db4.execSQL(sql_delete);
           db4.close();
           break;

       default:
           break;
       }
    }
}

方法二

import com.example.day014_sqliteopenhelper.db.MySqliteHelper;

import android.app.Activity;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.util.Log;
import android.view.View;

public class SqliteApiActivity extends Activity{

   private MySqliteHelper helper;

   @Override
   protected void onCreate(Bundle savedInstanceState) {
       // TODO Auto-generated method stub
       super.onCreate(savedInstanceState);
       setContentView(R.layout.activity_main);

       helper = new MySqliteHelper(SqliteApiActivity.this);

   }
   public void onClick(View v){
       switch (v.getId()) {
       case R.id.btn_create:
           //首先获取数据库
           SQLiteDatabase db = helper.getWritableDatabase();
           db.close();
           break;
       case R.id.btn_insert:
           //首先获取数据库
           SQLiteDatabase db1 = helper.getWritableDatabase();
           ContentValues values = new ContentValues();
           values.put("_id", 30);
           values.put("name", "aaa");
           values.put("age", 34);
           db1.insert("person", null, values);

           values = new ContentValues();
           values.put("_id", 31);
           values.put("name", "bbb");
           values.put("age", 34);

           /**
           * 参数1:表名        参数2: 如果添加的数据是null null    参数3:添加的数据
           */
           db1.insert("person", null, values);

           db1.close();
           break;
       case R.id.btn_query:
           //首先获取数据库
           SQLiteDatabase db2 = helper.getWritableDatabase();
           /**
           * 参数1:表名
           * 参数2:字段数组
           * 参数3:查询的条件       _id = ?
           * 参数4:查询条件的值       new String{"1"}
           * 参数5:分组字段
           * 参数6:在where条件后再次筛选
           * 参数7:查询排序
           */
           Cursor cursor = db2.query("person", null, null, null, null, null, null);
           while(cursor.moveToNext()){
//               int id = cursor.getInt(0);
//               String name = cursor.getString(1);
//               int age = cursor.getInt(2);
               int id = cursor.getInt(cursor.getColumnIndex("_id"));
               String name = cursor.getString(cursor.getColumnIndex("name"));
               int age = cursor.getInt(cursor.getColumnIndex("age"));
               System.out.println("==id==:"+id+"==name=="+name+"==age=="+age);

           }
           db2.close();

           break;
       case R.id.btn_update:
           //首先获取数据库
           SQLiteDatabase db3 = helper.getWritableDatabase();
           ContentValues values2 = new ContentValues();
           values2.put("name", "fffff");
           /**
           * 参数1:表名
           * 参数2:要修改的值
           * 参数3:where 条件语句    _id = ?
           * 参数4:条件语句的值       new String[]{"1"}
           */
           int num = db3.update("person", values2, "_id = ?", new String []{"1"});
           if (num>0) {
               Log.i("AAAAAA","修改成功");
           }else{
               Log.i("AAAAAA","修改失败");
           }
           db3.close();
           break;
       case R.id.btn_delete:
           //首先获取数据库
           SQLiteDatabase db4 = helper.getWritableDatabase();

           /**
           * 参数1:数据库表名
           * 参数2:where 条件语句   _id = ?
           * 参数3:条件语句的值       new String[]{"1"}
           */

           int num1 = db4.delete("person", "_id = ?", new String[]{1+""});

           if (num1>0) {
               Log.i("BBBBB","删除成功");
           }else{
               Log.i("BBBBB","删除失败");
           }
           db4.close();
           break;


       default:
           break;
       }
   }

}

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