SQLite数据库操作

在实际开发中经常会用到数据库的操作，这里简单总结下，也可以直接拿来用。

DatabaseHelper.java

package com.serial.db;

import android.content.ContentValues;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;

public class DatabaseHelper extends SQLiteOpenHelper {

    private static final String DB_NAME = "check_data.db"; //数据库名称
    private static final int version = 1; //数据库版本
    public static final String TABLE_NAME = "mydata"; 
    
    public DatabaseHelper(Context context) {
        super(context, DB_NAME, null, version);
        
    }
 
    @Override
    public void onCreate(SQLiteDatabase db) {
        String sql = "create table "+TABLE_NAME+"(username varchar(20) not null , password varchar(60) not null );";          
        db.execSQL(sql);
    }
 
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
       
 
    }
    
     
}

DBUtils.java

package com.serial.db;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

public class DBUtils {

    SQLiteDatabase db = null;
    DatabaseHelper database = null;
    
    public DBUtils(Context context){
        
        database = new DatabaseHelper(context);
        db = database.getReadableDatabase();
        
    }
    
    //插入数据方式，两种
    public void insertContent(ContentValues cv){
        
        db.insert(DatabaseHelper.TABLE_NAME,null,cv);//执行插入操作
    }
    
    public void insertCommon(String strSql){
        
        db.execSQL(strSql);//执行SQL语句
    }
    
    //删除数据方式，两种
    public void deleteArgs(String whereClause, String[] whereArgs){
        
        db.delete(DatabaseHelper.TABLE_NAME,whereClause,whereArgs);//执行删除
    }
    
    public void deleteSql(String delSql){
        
        db.execSQL(delSql);//执行删除操作
    }
    
    //修改数据的方式， 两种
    public void changeContent(ContentValues cv, String whereClause, String[] whereArgs ){
        
        db.update(DatabaseHelper.TABLE_NAME,cv,whereClause,whereArgs);//执行修改
    }
    
    public void changeCommon(String updateSql){
        
        db.execSQL(updateSql);//执行修改
    }
    
    //查询方式，两种
    public String searchCursor(){
        String username = "-1", password = "-1";
        Cursor c = db.query(DatabaseHelper.TABLE_NAME,null,null,null,null,null,null);//查询并获得游标
        if(c.moveToFirst()){//判断游标是否为空
            for(int i=0;i<c.getCount();i++){
                c.move(i);//移动到指定记录
                username = c.getString(c.getColumnIndex("username"));
                password = c.getString(c.getColumnIndex("password"));
            }
        }
        
        return username + "," + password;
    }
    
    public String searchRawQuery(){
        
        String username = "-1", password = "-1";
        Cursor cursor = db.rawQuery("select * from "+DatabaseHelper.TABLE_NAME+" where username=?",new String[]{"Jack Johnson"});
        if(cursor.moveToFirst()) {
            username = cursor.getString(cursor.getColumnIndex("username"));
            password = cursor.getString(cursor.getColumnIndex("password"));
        }
        
        return username + "-" + password;
    }
}

参考：http://www.cnblogs.com/Excellent/archive/2011/11/19/2254888.html