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(){

			@Override
			public 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(){

			@Override
			public 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(){
			@Override
			public 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(){

			@Override
			public 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;
	}
	@Override
	public void onCreate(SQLiteDatabase db) {
		db.execSQL(CREATE_BOOK);
		db.execSQL(CREATE_CATEGORY);
		Toast.makeText(mContext, "Create succeeded", Toast.LENGTH_SHORT).show();
	}

	@Override
	public 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