检查 SQLite Android 中是否存在数据 [英] Check if data is exist in SQLite Android

问题描述

我使用此函数从 SQlite 获取特定数据:

I use this function to get specific data from SQlite:

SearchRes getSresultByName(String name) {
    SQLiteDatabase db = this.getReadableDatabase();

    Cursor cursor = db.query(TABLE_WIKIRES, new String[] { KEY_ID,
            KEY_SNAME, KEY_SJSON }, KEY_SNAME + "=?",
            new String[] { name }, null, null, null, null);

    if (cursor != null)
        cursor.moveToFirst();

    SearchRes searchres = new SearchRes(Integer.parseInt(cursor.getString(0)),cursor.getString(1), cursor.getString(2));

    return searchres;
}

它工作得很好，我需要创建类似的函数来测试表中是否存在值，所以我尝试了这个:

And it works just fine, I need to create similar function to test if value is exist in the table, so I tried this:

boolean checkIfExist(String name) {
    SQLiteDatabase db = this.getReadableDatabase();

    Cursor cursor = db.query(TABLE_WIKIRES, new String[] { KEY_ID,
            KEY_SNAME, KEY_SJSON }, KEY_SNAME + "=?",
            new String[] { name }, null, null, null, null);


    if (cursor == null)
        return false;

    else
        return true;

}

但我总是得到正确的.你能帮我找出问题所在吗?

But I always get TRUE. Can you help me figure out what is the problem?

推荐答案

你不应该检查游标是否为空 你应该检查游标中是否存在任何东西

you should not be checking if cursor is null you should be checking if anything exists in the cursor

if(cursor.moveToFirst()){
    return true
}else{
    return false;
}

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