7

我有一个非常基本的情况：

我有一个大约 5k 行的表：

CREATE TABLE "words" ("id" INTEGER PRIMARY KEY  AUTOINCREMENT  NOT NULL , "name" TEXT NOT NULL , "def" TEXT NOT NULL, "rand" INTEGER)

我使用“UPDATE words SET rand=random()”定期更新

在 android 中，当我使用 rawQuery() 创建游标时，使用以下内容：

SELECT w.id, w.name, w.def, w.rand FROM words w ORDER BY w.rand ASC;

返回的游标没有以正确的顺序迭代。例如，它将按以下顺序输出具有 rand 值的列：

-1298882092
-2138143484
-1115732861
118839193
...

有谁知道这里发生了什么？这不应该工作吗？如果我在 SQLiteManager 中运行完全相同的查询，它会以正确的顺序返回结果，所以这似乎是 android/cursor 特定的。

更新：

这是android中的代码，我尝试了多种方法：

尝试1：

Cursor cursor = db.rawQuery("SELECT w.id, w.name, w.def, w.rand FROM words w ORDER BY w.rand ASC", new String[]{});

尝试2：

Cursor cursor = db.query("words", new String[]{"id", "name", "def", "rand"},
            null, null, null, null, "rand ASC");

在这两种情况下，我都会像下面这样迭代：

while(cursor.moveToNext()) {
    ...
    Log.i("Test", cursor.getInt(3));
    ...
}
4

2 回答 2

6

我解决了它，是一个简单的疏忽。random() 函数返回一个可以大于 java int 数据类型的值。这正在产生溢出。切换到 getLong() 一切正常。光标一直在正确迭代。

于 2011-01-30T21:23:01.947 回答
1

我在使用 android cursor、rawquery 和 group by 时遇到了问题。结果未排序。

这是表格：

public static final String I_ID = "iid";
public static final String I_QID = "qid";
public static final String I_STATUS = "status";
public static final String I_PDATE = "pub_date";
public static final String I_TYPE = "tipo";
public static final String I_TITLE = "titolo";
public static final String I_LINK = "link";
public static final String I_QR = "qrcode";
public static final String I_DESC = "descrizione";

private static final String C_ITEM_T = 
        "CREATE TABLE \""+T_ITEM+"\" ("+
        "\""+I_ID+"\" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,"+
        "\""+I_QID+"\" INTEGER NOT NULL REFERENCES "+T_QUERY+"("+Q_ID+") ,"+
        "\""+I_STATUS+"\" INTEGER NOT NULL,"+
        "\""+I_PDATE+"\" TEXT NOT NULL,"+
        "\""+I_TYPE+"\" TEXT NOT NULL,"+
        "\""+I_TITLE+"\" TEXT NOT NULL,"+
        "\""+I_LINK+"\" TEXT UNIQUE NOT NULL,"+
        "\""+I_QR+"\" TEXT UNIQUE NOT NULL,"+
        "\""+I_DESC+"\" TEXT"+
        ");";

public static final String A_ID = "aid";
public static final String A_IID = "iid";
public static final String A_SIZE = "grandezza";
public static final String A_DURATION = "durata";
public static final String A_CHANNELS = "canali";
public static final String A_RATE = "sampleRate";
public static final String A_TORRENT = "torrent";
public static final String A_DOWNLOAD = "download";
public static final String A_LICENSE_URL = "licenza_url";
public static final String A_TAGS = "tags";
public static final String A_CREATOR = "creatore";

private static final String C_ATTR_T = 
        "CREATE TABLE \""+T_ATTR+"\" ("+
        "\""+A_ID+"\" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,"+
        "\""+A_IID+"\" INTEGER NOT NULL REFERENCES "+T_ITEM+"("+I_ID+") ,"+
        "\""+A_SIZE+"\" LONG NOT NULL,"+
        "\""+A_DURATION+"\" LONG NOT NULL,"+
        "\""+A_CHANNELS+"\" TEXT NOT NULL,"+
        "\""+A_RATE+"\" TEXT NOT NULL,"+
        "\""+A_TORRENT+"\" TEXT NOT NULL,"+
        "\""+A_DOWNLOAD+"\" TEXT NOT NULL,"+
        "\""+A_LICENSE_URL+"\"TEXT,"+
        "\""+A_TAGS+"\" TEXT,"+
        "\""+A_CREATOR+"\" TEXT,"+
        "UNIQUE ("+A_ID+","+A_IID+")"+
        ");";

这是我的查询：

public static final String FILL_GRID = "SELECT * "+
        "FROM "+ Db.T_ITEM + " i " +
        "LEFT OUTER JOIN "+Db.T_ATTR+" a ON ( i."+Db.I_ID+"=a."+Db.A_IID+ ")"+ 
        " WHERE i."+Db.I_QID+" = ? AND i."+Db.I_STATUS+" <> "+Db.STATUS_DELETED +
                    " GROUP BY ? ";

以及我如何使用它：

Cursor c = db.rawQuery(FILL_GRID, new String[]{String.valueOf(qid), order});

我确定 qid 是一个整数，并订购 i.titolo ASC 或 DESC

对我有用的唯一解决方法是在 rawquery 调用方法中修改通过 clausole 移动组的查询：

public static final String FILL_GRID = "SELECT * "+
        "FROM "+ Db.T_ITEM + " i " +
        "LEFT OUTER JOIN "+Db.T_ATTR+" a ON ( i."+Db.I_ID+"=a."+Db.A_IID+ ")"+ 
        " WHERE i."+Db.I_QID+" = ? AND i."+Db.I_STATUS+" <> "+Db.STATUS_DELETED;

Cursor c = db.rawQuery(FILL_GRID + " ORDER BY " + order, new String[]{String.valueOf(qid)});
于 2012-06-15T12:45:18.797 回答