数据库android操作

（1）建立数据库结构：

SqliteHelper.java

 

package USTC;

 

import android.content.Context;

import android.database.sqlite.SQLiteDatabase;

import android.database.sqlite.SQLiteOpenHelper;

import android.database.sqlite.SQLiteDatabase.CursorFactory;

import android.util.Log;

 

 

//该文件主要用来形成数据库的结构。由于在手机上没有实际的库，需要在第一次

//运行时建立库结构。

public class SqliteHelper extends SQLiteOpenHelper {

//用来保存 UserID、Access Token、Access Secret的表名

    public static final String TB_NAME="users";

    public SqliteHelper(Context context, String name, CursorFactory factory, int version) {

        super(context, name, factory, version);

    }

    //创建表

    @Override

    public void onCreate(SQLiteDatabase db) {

     try

     {

     db.execSQL("CREATE TABLE IF NOT EXISTS " 

                   +"TBVersion( SOFTNAME  varchar primary key," +

                     "VERSION varchar,"+ 

                     "BZ  varchar"+

                    ")");

        db.execSQL("CREATE TABLE IF NOT EXISTS "+

                TB_NAME+"( ID  integer primary key," +

                 "USERNAME varchar,"+ 

                 "PASSWD  varchar"+

                ")");

        Log.e("Database","onCreate");

     }catch(Exception e){

            e.printStackTrace();

        }

    }

    //更新表

 

    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

        db.execSQL("DROP TABLE IF EXISTS " + TB_NAME);

        onCreate(db);

        Log.e("Database","onUpgrade");

    }

    //更新列

     public void updateColumn(SQLiteDatabase db, String oldColumn, String newColumn, String typeColumn){

        try{

            db.execSQL("ALTER TABLE " +

                    TB_NAME + " CHANGE " +

                    oldColumn + " "+ newColumn +

                    " " + typeColumn

            );

        }catch(Exception e){

            e.printStackTrace();

        }

    } 

}

(2)建立DM

package USTC;

import java.util.ArrayList;

import java.util.List;

import android.content.ContentValues;

import android.content.Context;

import android.database.Cursor;

import android.database.sqlite.SQLiteDatabase;

import android.util.Log;

public class DM {

// 数据库名称

private static String DB_NAME = "mysinaweibo.db";

// 数据库版本

private static int DB_VERSION = 1;

private SQLiteDatabase db;

private SqliteHelper dbHelper;

public DM(Context context) {

dbHelper = new SqliteHelper(context, DB_NAME, null, DB_VERSION);

db = dbHelper.getWritableDatabase();

}

public Cursor getsql(String sql, String[] obj) {

try {

Cursor cursor = db.rawQuery(sql, obj);

return cursor;

} catch (Exception ex) {

Log.e("数据库操作", ex.toString());

return null;

}

}

public void Execsql(String sql, Object[] obj) {

try {

if(obj==null)db.execSQL(sql);

else

db.execSQL(sql, obj);

} catch (Exception ex) {

Log.e("数据库操作", ex.toString());

}

}

}

（3）操作实体对象数据

// 获取users表中的UserID、Access Token、Access Secret的记录

public List<UserInfo> GetUserList(Boolean isSimple) {

List<UserInfo> userList = new ArrayList<UserInfo>();

String sql = "select * from " + SqliteHelper.TB_NAME;

Cursor cursor = this.getsql(sql, null);// (SqliteHelper.TB_NAME, null,

// null, null, null, null,null);

Integer num = cursor.getCount();

if (num > 0) {

cursor.moveToFirst();

UserInfo user = new UserInfo();

user.setId(cursor.getString(0));

user.setUserName(cursor.getString(1));

user.setPasswd(cursor.getString(2));

userList.add(user);

cursor.moveToNext();

}

cursor.close();

return userList;

}

// 判断users表中的是否包含某个UserID的记录

public Boolean HaveUserInfo(String UserId) {

Boolean b = false;

Cursor cursor = db.query(SqliteHelper.TB_NAME, null, UserInfo.ID + "="

+ UserId, null, null, null, null);

b = cursor.moveToFirst();

Log.e("HaveUserInfo", b.toString());

cursor.close();

return b;

}

 

// 添加users表的记录

public void SaveUserInfo(UserInfo user) {

UserInfo.ID = user.getId();

UserInfo.USERNAME = user.getUserName();

UserInfo.PASSWD = user.getPasswd();

String sql = "insert into " + SqliteHelper.TB_NAME

+ "(ID,USERNAME,PASSWD) VALUES(?,?,?)";

String[] tmp = new String[] { UserInfo.ID, UserInfo.USERNAME,

UserInfo.PASSWD };

Execsql(sql, tmp);

// Long uid = db.insert(SqliteHelper.TB_NAME, UserInfo.ID, values);

// Log.e("SaveUserInfo",uid+"");

// return uid;

}

// 删除users表的记录

public int DelUserInfo(String UserId) {

int id = db.delete(SqliteHelper.TB_NAME, "ID=" + UserId, null);

Log.e("DelUserInfo", id + "");

return id;

}