SQL数据库储存

一、运行效果图

1.创建运行之后的效果图：

 

2.添加运行之后的效果图：

 

3.更新运行之后的效果图：

 

4.删除运行之后的效果图：

 

5.查询运行之后的效果图：

 

二、 核心代码

1.MainActivity的代码：

public class MainActivity extends Activity {    private MyDatabaseHelper dbHelper;@Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        dbHelper = new MyDatabaseHelper(this,"BookStore.db",null,2);       Button createDatabase = (Button) findViewById(R.id.create_database);        createDatabase.setOnClickListener(new OnClickListener(){@Overridepublic void onClick(View view) {dbHelper.getWritableDatabase();}                });        Button addData = (Button)findViewById(R.id.add_data);        addData.setOnClickListener(new OnClickListener(){        public void onClick(View view){        SQLiteDatabase db = dbHelper.getWritableDatabase();        ContentValues values = new ContentValues();        //开始组装第一条数据        values.put("name", "The Da Vinci Code");        values.put("author", "Dan Brown");        values.put("pages", 454);        values.put("price", 16.96);        db.insert("Book", null, values);        //插入第一条数据        values.clear();        //开始组装第二条数据        values.put("name","The Lost Symbol");        values.put("author", "Dan Brown");        values.put("pages", 510);        values.put("price",19.95);        db.insert("Book", null, values);                }        });       Button updateData = (Button)findViewById(R.id.update_data);        updateData.setOnClickListener(new OnClickListener(){@Overridepublic void onClick(View view) {SQLiteDatabase db = dbHelper.getWritableDatabase();ContentValues values = new ContentValues();values.put("price", 10.99);db.update("Book",values,"name = ?",new String[]{"The DaVinci code"});}                });                Button deleteButton = (Button)findViewById(R.id.delete_data);        deleteButton.setOnClickListener(new OnClickListener(){@Overridepublic void onClick(View view) {SQLiteDatabase db = dbHelper.getWritableDatabase();db.delete("Book","pages > ?",new String[]{"500"});}                });       Button queryButton = (Button)findViewById(R.id.query_data);        queryButton.setOnClickListener(new OnClickListener(){@Overridepublic void onClick(View view) {SQLiteDatabase db = dbHelper.getWritableDatabase();//查询Book表中所有的数据Cursor cursor = db.query("Book",null,null,null,null,null,null);if(cursor.moveToFirst()){do{//遍历Curson对象，取出数据并打印String name = cursor.getString(cursor.getColumnIndex("name"));String author = cursor.getString(cursor.getColumnIndex("author"));int pages = cursor.getInt(cursor.getColumnIndex("pages"));double price = cursor.getDouble(cursor.getColumnIndex("price"));Log.d("MainActivity","book name is" + name);Log.d("MainActivity","book author is" + author);Log.d("MainActivity","book pages is" + pages);Log.d("MainActivity","book price is" + price);}while(cursor.moveToNext());}cursor.close();}                });    }}

2.MyDatabaseHelper的代码：

public class MyDatabaseHelper extends SQLiteOpenHelper{public static final String CREATE_BOOK = "create table Book("+"id integer primary key autoincrement,"+"author text,"+"price real,"+"pages integer,"+"name text)";public static final String CREATE_CATEGORY = "create table Category("+"id integer primary key autoincrement,"+"category_name text,"+"category_code integer)";private Context mContext;public MyDatabaseHelper(Context context, String name,CursorFactory factory, int version) {super(context, name, factory, version);mContext = context;}@Overridepublic void onCreate(SQLiteDatabase db) {db.execSQL(CREATE_BOOK);db.execSQL(CREATE_CATEGORY);Toast.makeText(mContext, "Create succeeded", Toast.LENGTH_SHORT).show();}@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {db.execSQL("drop table if exists Book");db.execSQL("drop table if exists Category");onCreate(db);}}

3.activity_main的代码：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical" >    <Button        android:id="@+id/create_database"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="@string/hello_world" />    <Button        android:id="@+id/add_data"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="@string/Add"/>    <Button        android:id="@+id/update_data"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="@string/Update"/>     <Button        android:id="@+id/delete_data"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="@string/Delete"/>     <Button        android:id="@+id/query_data"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="@string/Query"/>    </LinearLayout>

三、遇见的问题：

     1. 刚点击查询按钮的时候，Logcat中不能显示出运行效果

     2.从Windows的命令中不能进行添加及以下的效果