17 Android 数据库

package com.db.test;

import java.sql.SQLDataException;

import android.R.string;
import android.app.Activity;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
import android.os.Bundle;
import android.util.Log;

public class DBTestActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        MyDataBaseOpenHelper mydb=new MyDataBaseOpenHelper(this);
        mydb.getReadableDatabase();
        
//        mydb.insertDB("Tom", "BJING");
//        mydb.insertDB("Jack", "NANJING");
//        mydb.insertDB("Ting", "TIDDA");
        mydb.deleteDB("Tom");
        Cursor cs=mydb.queryDB();
        cs.moveToFirst();
        while(!cs.isLast())
        {
        	String str1=cs.getString(cs.getColumnIndex("name"));
        	String str2=cs.getString(cs.getColumnIndex("address"));
        	Log.d(">>>>姓名<<<<", str1);
        	Log.d(">>>>地址<<<<", str2);
        	cs.moveToNext();
        }
        
}

class MyDataBaseOpenHelper extends SQLiteOpenHelper{

	Context context;
	private static final String DB_NAME="mydb.db";//数据库的名字
	private static final int VERSION=1;//数据库的版本
	public MyDataBaseOpenHelper(Context context) {
		super(context, DB_NAME, null, VERSION);
		// TODO Auto-generated constructor stub
	}
	@Override
	public void onCreate(SQLiteDatabase db) {
		// TODO Auto-generated method stub
		//建表语句执行
		String sqlStr="create table person(_id integer primary key "
				+ "autoincrement,name text,address text)";
		//执行sql语句
		db.execSQL(sqlStr);
		
	}
	@Override
	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
		// TODO Auto-generated method stub
		String sql="alter table person add age integer";
		db.execSQL(sql);
	}
	/**
	 * 插入数据
	 * @param name
	 * @param address
	 * @return
	 */
	public long insertDB(String name,String address)
	{
		SQLiteDatabase db=this.getWritableDatabase();
		ContentValues cv=new ContentValues();
		cv.put("name", name);
		cv.put("address", address);
		
		return db.insert("person", null, cv);
	}
	/**
	 * 删除数据
	 * @param id
	 * @return
	 */
	public long deleteDB(String name)
	{
		SQLiteDatabase db=this.getWritableDatabase();
		String where="name=?";
		String [] whereValue={name};
		
		return db.delete("person", where, whereValue);
	}
	/**
	 * 更新数据
	 * @param id
	 * @param name
	 * @param address
	 * @return
	 */
	public long updateDB(String id ,String name,String address){
		SQLiteDatabase db=this.getWritableDatabase();
		ContentValues cv=new ContentValues();
		cv.put("name", name);
		cv.put("address", address);
		String where="_id=?";
		String[] whereValue={id};
		
		return db.update("person", cv, where, whereValue);
	}
    
	public Cursor queryDB()
	{
		SQLiteDatabase db=this.getReadableDatabase();
		Cursor cursor=db.query("person", null, null, null, null, null, null);
		return cursor;
	}
	
	
}
}