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。我已经使用这个数据库来存储用户。但是，当我想更新它时，它无法正常工作。

logcat为空

这是我尝试通过硬编码来更新的功能：

 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();
    }
}

我不能做错的事。希望有人能看到它。这是一个类似的问题：Android SQLite update query not working?但它并没有解决我的问题。我变得绝望，如果有人能帮助我，我真的很感激。

以下是我的数据库的图片（上传图片的声誉不足）：http://nl.tinypic.com/r/mm8nxg/8

以下代码无效：

    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);

使用execSQL()而非rawQuery()进行此类查询。

rawQuery()只编译SQL但不运行它。 execSQL()编译并运行它。（带rawQuery()的SQL仅在移动返回的游标时执行。）

Answer 2

您需要拥有原始数据库创建脚本，但您还需要告诉数据库您需要哪些更改。

对我来说，我创建了这个字符串：

        private static final String ALTER_TABLE = 
             "ALTER TABLE player ADD COLUMN showscores INTEGER default 1";

这会在我现有的数据库中添加一列。但我必须在onUpgrade中实现这一点。

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
                    + newVersion + ". No data will be destroyed");
            if (oldVersion != newVersion) {
                db.execSQL(ALTER_TABLE);
            }
        }

Answer 3

在构造函数

中

public DatabaseHandler(Context context) {
    super(context, DATABASE_NAME", null, DATABASE_VERSION); // be aware of that number, when you change your db add one plus
    this.onCreate(this.getWritableDatabase());
}

及以下

@Override
public void onCreate(SQLiteDatabase db) {

    db.execSQL(createTable);//execute all querys to create it
}

使用sqlite更新数据库时没有错误但是没有更新（android应用程序）

3 个答案: