Question

如果我添加相同的评论（例如：“www.google.lv”），则会再次创建此评论。我希望这个cament不能重复，但是创造了最新的。我是包括insertWithOnConflict，但它不起作用。有我的代码：

    public class SQLiteAdapter {

public static final String MYDATABASE_NAME = "MY_DATABASE";
public static final String MYDATABASE_TABLE = "MY_TABLE";
public static final int MYDATABASE_VERSION = 1;
public static final String KEY_ID = "_id";
public static final String KEY_CONTENT = "Content";

//create table MY_DATABASE (ID integer primary key, Content text not null);
private static final String SCRIPT_CREATE_DATABASE =
"create table " + MYDATABASE_TABLE + " ("
+ KEY_ID + " integer primary key autoincrement, "
+ KEY_CONTENT + " text not null);";

private SQLiteHelper sqLiteHelper;
private SQLiteDatabase sqLiteDatabase;

private Context context;

public SQLiteAdapter(Context c){
context = c;
}

public SQLiteAdapter openToRead() throws android.database.SQLException {
sqLiteHelper = new SQLiteHelper(context, MYDATABASE_NAME, null, MYDATABASE_VERSION);
sqLiteDatabase = sqLiteHelper.getReadableDatabase();
return this;
}

public SQLiteAdapter openToWrite() throws android.database.SQLException {
sqLiteHelper = new SQLiteHelper(context, MYDATABASE_NAME, null, MYDATABASE_VERSION);
sqLiteDatabase = sqLiteHelper.getWritableDatabase();
return this;
}

public void close(){
sqLiteHelper.close();
}

public long insert(String content){

ContentValues contentValues = new ContentValues();
contentValues.put(KEY_CONTENT, content);
return sqLiteDatabase.insertWithOnConflict(MYDATABASE_TABLE, null, contentValues, SQLiteDatabase.CONFLICT_REPLACE);
}

public int deleteAll(){
return sqLiteDatabase.delete(MYDATABASE_TABLE, null, null);
}

public List<Comment> getAllComments() {
    List<Comment> comments = new ArrayList<Comment>();
    String[] columns = new String[]{KEY_ID, KEY_CONTENT};
    Cursor cursor = sqLiteDatabase.query(MYDATABASE_TABLE,
            columns, null, null, null, null, null);

    cursor.moveToFirst();
    while (!cursor.isAfterLast()) {
      Comment comment = cursorToComment(cursor);
      comments.add(comment);
      cursor.moveToNext();
    }
    // Make sure to close the cursor
    cursor.close();
    return comments;

  }
private Comment cursorToComment(Cursor cursor) {
    Comment comment = new Comment();
    comment.setId(cursor.getLong(0));
    comment.setComment(cursor.getString(1));
    return comment;
  }
public List queueAll(){
String[] columns = new String[]{KEY_ID, KEY_CONTENT};
Cursor cursor = sqLiteDatabase.query(MYDATABASE_TABLE, columns,
  null, null, null, null, null);
cursor.moveToFirst();
  cursor.moveToNext();


return null;
}

public class SQLiteHelper extends SQLiteOpenHelper {

public SQLiteHelper(Context context, String name,
  CursorFactory factory, int version) {
 super(context, name, factory, version);
}

@Override
public void onCreate(SQLiteDatabase db) {
 // TODO Auto-generated method stub
 db.execSQL(SCRIPT_CREATE_DATABASE);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
 // TODO Auto-generated method stub

}

}

}

Answer 1

实际上你滥用 insertWithOnConflict 。在您的方法插入中，您不会向ContentValues提供id列，因此 insertWithOnConflict 只会添加另一条带有新ID和现有内容的记录。如果您提供表中已存在的id（您的主键）， insertWithOnConflict 将有所帮助。在您的情况下，您应首先找到现有注释的ID，然后更新它或插入一个新注释。

为什么SOlite更换不起作用？

1 个答案: