SQlite – Android – 外键语法

我一直在试图让外键在我的Android sqlite数据库中工作。我试过下面的语法，但它给了我一个力close：

private static final String TASK_TABLE_CREATE = "create table "
            + TASK_TABLE + " (" + TASK_ID
            + " integer primary key autoincrement," + TASK_TITLE
            + " text not null," + TASK_NOTES + " text not null,"
    + TASK_DATE_TIME + " text not null,FOREIGN KEY ("+TASK_CAT+") REFERENCES "+CAT_TABLE+" ("+CAT_ID+"));";

任何想法我可能做错了什么？如果你需要看到其他表结构，那么我可以，它只是一个非常简单的结构，第二个具有ID和名称。

编辑：

这里是错误：

03-13 13:42:35.389:
ERROR/AndroidRuntime(312): Caused by:
android.database.sqlite.sqliteException:
unkNown column “taskCat” in foreign
key deFinition: create table reminders
(_id integer primary key
autoincrement,task_title text not
null,notes text not null,
reminder_date_time text not null,
FOREIGN KEY (taskCat) REFERENCES
category (_id));

您必须首先定义TASK_CAT列，然后在其上设置外键。

private static final String TASK_TABLE_CREATE = "create table "
        + TASK_TABLE + " (" 
        + TASK_ID + " integer primary key autoincrement," 
        + TASK_TITLE + " text not null," 
        + TASK_NOTES + " text not null,"
        + TASK_DATE_TIME + " text not null,"
        + TASK_CAT + " integer,"
        + " FOREIGN KEY ("+TASK_CAT+") REFERENCES "+CAT_TABLE+"("+CAT_ID+"));";

更多信息，你可以找到sqlite外键doc。