java - 使用 sqlite 更新数据库时没有错误，但没有更新(android 应用程序)

Question

我尝试使用 sqlite 更新我的数据库。一切运行良好，但数据库没有更新。我使用这个数据库来存储用户。但是当我想更新它时，它不起作用。

logcat 为空

这是我尝试通过硬编码来更新的函数:

 public void updateUser(String email, String total_usage) {
        SQLiteDatabase db = this.getWritableDatabase();
        db.rawQuery("UPDATE login SET total_usage = 132 WHERE email = 'sampleMail'", null);
        db.rawQuery("UPDATE login SET total_usage = 132 WHERE email = 'sampleMail'", null);
    }

也许问题出在其他地方。这是完整的java文件:

public class DatabaseHandler extends SQLiteOpenHelper {

    // All Static variables
    // Database Version
    private static final int DATABASE_VERSION = 1;

    // Database Name
    private static final String DATABASE_NAME = "android_api";

    // Login table name
    private static final String TABLE_LOGIN = "login";

    // Login Table Columns names
    private static final String KEY_ID = "id";
    private static final String KEY_NAME = "name";
    private static final String KEY_EMAIL = "email";
    private static final String KEY_UID = "uid";
    private static final String KEY_CREATED_AT = "created_at";
    private static final String KEY_TOTAL_USAGE = "total_usage";

    public DatabaseHandler(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    // Creating Tables
    @Override
    public void onCreate(SQLiteDatabase db) {
        String CREATE_LOGIN_TABLE = "CREATE TABLE " + TABLE_LOGIN + "("
                + KEY_ID + " INTEGER PRIMARY KEY," 
                + KEY_NAME + " TEXT,"
                + KEY_EMAIL + " TEXT UNIQUE,"
                + KEY_UID + " TEXT,"
                + KEY_CREATED_AT + " TEXT,"
                + KEY_TOTAL_USAGE + " TEXT);";
        db.execSQL(CREATE_LOGIN_TABLE);
    }

    // Upgrading database
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // Drop older table if existed
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_LOGIN);

        // Create tables again
        onCreate(db);
    }

    /**
     * Storing user details in database
     * */
    public void addUser(String name, String email, String uid, String created_at) {
        SQLiteDatabase db = this.getWritableDatabase();


        ContentValues values = new ContentValues();
        values.put(KEY_NAME, name); // Name
        values.put(KEY_EMAIL, email); // Email
        values.put(KEY_UID, uid); // Email
        values.put(KEY_CREATED_AT, created_at); // Created At
    //    values.put(KEY_TOTAL_USAGE, total_usage); // Total_usage

        // Inserting Row
        db.insert(TABLE_LOGIN, null, values);

        db.close(); // Closing database connection
    }

    /**
     * Storing user details in database
     * */
    public void updateUser(String email, String total_usage) {
        SQLiteDatabase db = this.getWritableDatabase();
        db.rawQuery("UPDATE login SET total_usage = 132 WHERE email = 'sampleMail'", null);
        db.rawQuery("UPDATE login SET total_usage = 132 WHERE email = 'sampleMail'", null);
    }

    /**
     * Getting user data from database
     * */
    public HashMap<String, String> getUserDetails(){
        HashMap<String,String> user = new HashMap<String,String>();
        String selectQuery = "SELECT  * FROM " + TABLE_LOGIN;

        SQLiteDatabase db = this.getReadableDatabase();
        Cursor cursor = db.rawQuery(selectQuery, null);
        // Move to first row
        cursor.moveToFirst();
        if(cursor.getCount() > 0){
            user.put("name", cursor.getString(1));
            user.put("email", cursor.getString(2));
            user.put("uid", cursor.getString(3));
            user.put("created_at", cursor.getString(4));
        }
        cursor.close();
        db.close();
        // return user
        return user;
    }

    /**
     * Getting user login status
     * return true if rows are there in table
     * */
    public int getRowCount() {
        String countQuery = "SELECT  * FROM " + TABLE_LOGIN;
        SQLiteDatabase db = this.getReadableDatabase();
        Cursor cursor = db.rawQuery(countQuery, null);
        int rowCount = cursor.getCount();
        db.close();
        cursor.close();

        // return row count
        return rowCount;
    }

    /**
     * Re crate database
     * Delete all tables and create them again
     * */
    public void resetTables(){
        SQLiteDatabase db = this.getWritableDatabase();
        // Delete All Rows
        db.delete(TABLE_LOGIN, null, null);
        db.close();
    }
}

我不知道我做错了什么。希望有人能看到它。这是一个类似的问题:Android SQLite update query not working?但这并没有解决我的问题。我越来越绝望，如果有人能帮助我，我真的很感激。

这是我的数据库的图片(没有足够的声誉上传图像):http://nl.tinypic.com/r/mm8nxg/8

<小时/>

下面的代码不起作用:

    public void updateUser(String email, String total_usage) {
        String selectQuery = "UPDATE login SET total_usage = 132 WHERE email = 'sampleMail'";

        SQLiteDatabase db = this.getWritableDatabase();

        db.execSQL(selectQuery);
}

Answer 1

db.rawQuery("UPDATE login SET total_usage = 132 WHERE email = 'sampleMail'", null);     
db.rawQuery("UPDATE login SET total_usage = 132 WHERE email = 'sampleMail'", null);

对于此类查询，请使用 execSQL() 而不是 rawQuery()。

rawQuery() 仅编译 SQL，但不运行它。 execSQL() 编译并运行它。 (只有当您移动返回的游标时，才会执行带有 rawQuery() 的 SQL。)