Question

我有两个1：1关系的表，我正在使用内容提供程序和cursorloader。

如何使用游标加载器进行连接查询？我可以使用内容提供程序中的rawSql以某种方式破解它，但是如何在游标加载器构造函数中执行它是超出我的。

非常感谢！

private static final String CREATE_TABLE_ARTICLES = "create table "
            + TABLE_ARTICLES + "("
            + COLUMN_ARTICLE_ID + " integer primary key autoincrement, "
            + COLUMN_URL + " text not null unique, "
            + COLUMN_TITLE + " text not null, "
            + COLUMN_PRICE + " text not null, "
            + COLUMN_ADDED + " text not null, "
            + COLUMN_IMG_URL + " text);";

    private static final String CREATE_TABLE_ARTICLE_DETAIL = "create table "
            + TABLE_ARTICLE_DETAILS + "("
            + COLUMN_ARTICLE_DETAIL_ID + " integer primary key autoincrement, "
            + COLUMN_DESC + " text not null, "
            + COLUMN_LOCALITY + " text, "
            + COLUMN_TYPE + " text not null, "
            + COLUMN_SELLER + " text not null, "
            + COLUMN_SELLER_PHONE + " text, "
            + COLUMN_IMAGE_COUNT + " integer default 0, "
            + COLUMN_ARTICLE + " integer, foreign key (" + COLUMN_ARTICLE + ") references " + TABLE_ARTICLES + "(" + COLUMN_ARTICLE_ID + "));";

Answer 1

实际上，您不必使用自定义任务加载器。简而言之，一种解决方案是创建一个Uri“content：// AUTHORITY / TableArticlesWithDetail”。然后在您的内容提供程序中，检查该Uri并执行原始SQL以进行连接。

有关详细信息，请参阅how to use join query in CursorLoader when its constructor does not support it。

Answer 2

最简单的解决方案是创建一个连接表的视图，并使用Uri从CursorLoader访问视图。

Answer 3

Cursor c = db.query(
    RefuelTable.TABLE_NAME + " , " + ExpenseTable.TABLE_NAME,
    Utils.concat(RefuelTable.PROJECTION, ExpenseTable.PROJECTION),
     RefuelTable.EXP_ID + " = " + ExpenseTable.ID + " AND  "  +    RuelTable.ID + " = " +  id ,
    null,
    null,
    null,
    null);

喜欢这个

CursorLoader - 两个表连接查询？

3 个答案: