Question

我创建了一个处理程序类，它使用几个方法作为插入/删除，并从表中返回一个特定的值。但是，当我在活动中创建处理程序并尝试插入产品类（将其视为字符串）时，在此之前，应用程序崩溃。我检查product变量返回一个正确的字符串，一切似乎都很好，我一直得到下面的错误。非常感谢！

cerygo.grocerygo E/AndroidRuntime: FATAL EXCEPTION: main
                                                                             Process: ca.comp3004.grocerygo.grocerygo, PID: 10703
                                                                             android.database.sqlite.SQLiteException: near "productname": syntax error (code 1): , while compiling: CREATE TABLE products(_id INTEGER PRIMARY KEY AUTOINCREMENT productname TEXT );

这是我的处理程序类

public class MyDBHandler extends SQLiteOpenHelper{
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "productList.db";
public static final String TABLE_PRODUCTS = "products";
public static final String COLUMN_ID = "_id";
public static final String COLUMN_PRODUCTNAME = "productname";

public MyDBHandler(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
    super(context, DATABASE_NAME, factory, DATABASE_VERSION);
}

public MyDBHandler(Context context, String name, SQLiteDatabase.CursorFactory factory, int version, DatabaseErrorHandler errorHandler) {
    super(context, name, factory, version, errorHandler);
}

@Override
public void onCreate(SQLiteDatabase db) {
    String query = "CREATE TABLE " + TABLE_PRODUCTS + "(" +
            COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT " +  COLUMN_PRODUCTNAME + " TEXT " + ");";
        db.execSQL(query);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL("DROP TABLE IF EXISTS " + TABLE_PRODUCTS);
    onCreate(db);
}

//Add new a row
public void addProduct(Product product){
    ContentValues values = new ContentValues();
    values.put(COLUMN_PRODUCTNAME, product.get_productName());
    SQLiteDatabase db = getWritableDatabase();
    db.insert(TABLE_PRODUCTS, null, values);
    db.close();
}

//Delete product
public void deleteProduct(String productName){
    SQLiteDatabase db = getWritableDatabase();
    db.execSQL("DELETE FROM " + TABLE_PRODUCTS + " WHERE "+ COLUMN_PRODUCTNAME + "=\"" + productName + "\";");
}

public ArrayList<String> dbToAS(){
    ArrayList<String> dbAS = null;
    SQLiteDatabase db = getWritableDatabase();
    String query = "SELECT * FROM " + TABLE_PRODUCTS + " WHERE 1";

    //Cursor pointer
    Cursor c = db.rawQuery(query, null);
    //move to first row
    c.moveToFirst();

    while(!c.isAfterLast()){
        if(c.getString(c.getColumnIndex("productname")) != null){
            dbAS.add(c.getString(c.getColumnIndex("productname")));
        }
    }
    db.close();
    return dbAS;
}

}

使用处理程序的活动

   MyDBHandler dbHandler = new MyDBHandler(this, null, null, 1);
   product = data.getString("Product");
        productName.setText("Product: " + product);
        //Individual request

        Button button = (Button) findViewById(R.id.addItem);
        final String finalProduct = data.getString("Product");
        button.setOnClickListener(new View.OnClickListener() {

            public void onClick(View view) {
                dbHandler.addProduct(new Product(product));
                Toast.makeText(ItemPop.this, "Added", Toast.LENGTH_SHORT).show();
            }
        });

Answer 1

您需要用逗号分隔列。

您正在尝试执行以下语句：

CREATE TABLE products(_id INTEGER PRIMARY KEY AUTOINCREMENT productname TEXT);

你应该执行这个：

CREATE TABLE products(_id INTEGER PRIMARY KEY AUTOINCREMENT, productname TEXT);

SQLiteException代码：1

1 个答案: