android - 如何在android中的SQlite中删除整行

Question

我创建了一个名为 MSqliteHelper 的类来帮助我在 android 项目中使用 SQlite

public class MSqliteHelper extends SQLiteOpenHelper{
private static final String DATABASE_NAME = "userData"; //dataBaseName
private static final int DATABASE_VERSION = 1;  
private SQLiteDatabase db;

public MSqliteHelper(Context context) { 
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
    db = this.getWritableDatabase();
}

然后我像这样创建表

@Override
public void onCreate(SQLiteDatabase db) {

    String DATABASE_CREATE_TABLE =
        "create table userData ("
            + "HTTPorS TEXT,"
            + "IPHostName TEXT,"
            + "port TEXT,"
            + "userName TEXT,"
            + "password TEXT,"
            + "saveOption TEXT"
        + ");";
    db.execSQL(DATABASE_CREATE_TABLE);
}

我可以用这个方法来添加整行数据

    public long create(String HTTPorS, String IPHostName, String port, String userName,     String password, String saveOption) {
    ContentValues args = new ContentValues();
    args.put("HTTPorS", HTTPorS);
    args.put("IPHostName", IPHostName);
    args.put("port", port);
    args.put("userName", userName);
    args.put("password", password);
    args.put("saveOption", saveOption);
    return db.insert("userData", null, args);
}

我有一种方法可以像这样删除索引处的整行数据

    public int delete(long rowId) {
    return db.delete("userData",    
    "_ID=" + rowId,         
    null                
    );
}

但每次我调用这个删除方法时，应用程序都会崩溃

而错误信息是这样的-----

E/AndroidRuntime(2976): android.database.sqlite.SQLiteException: no such column: _ID: , while compiling: DELETE FROM userData WHERE _ID=2

我哪里做错了？

感谢您的帮助!

Answer 1

您必须创建包含 _id 的表。例如

String DATABASE_CREATE_TABLE =
    "create table userData ("
        + "_id INTEGER PRIMARY KEY AUTOINCREMENT,"
        + "HTTPorS TEXT,"
        + "IPHostName TEXT,"
        + "port TEXT,"
        + "userName TEXT,"
        + "password TEXT,"
        + "saveOption TEXT"
    + ");";