Android复合主键？
谁能告诉我如何在 Android 1.6 中声明包含自动增量 _id 列的复合主键？我不确定语法。当我尝试添加值时，我最终只是在Java中强制执行它（其中registrationNumber + date在表中必须是唯一的）：
Cursor fuelUpsCursor = getFuelUps(registrationNumber, date);
if(!fuelUpsCursor.moveToNext())
{
//add registrationNumber and date
}
我真的不需要_id列，但如果表不需要，它会让生活变得棘手有一个。
干杯， 巴里
Can anyone tell me how to declare a composite primary key in Android 1.6 which includes an autoincrement _id column? I'm not sure of the syntax. I've ended up just enforcing it in Java when I try to add values (where registrationNumber + date has to be unique in the table):
Cursor fuelUpsCursor = getFuelUps(registrationNumber, date);
if(!fuelUpsCursor.moveToNext())
{
//add registrationNumber and date
}
I don't really need the _id column but it can make life tricky if tables don't have one.
Cheers,
Barry
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你的问题没有多大意义。您的主题行要求“复合外键”，您的第一句话要求“复合主键”和
AUTOINCRMENT，然后您的示例代码会忽略它。我将这样解释您的问题：您希望表中的
_ID INTEGER PRIMARY KEY AUTOINCRMENT列能够使用 Android 的CursorAdapter，但您还希望确保其他两列的组合是唯一的。在这种情况下，我认为您想要使用
UNIQUE约束：Your question does not make much sense. Your subject line asks for a "composite foreign key", your first sentence asks for a "composite primary key" with an
AUTOINCREMENTthat your sample code then ignores.I am going to interpret your question this way: You want an
_ID INTEGER PRIMARY KEY AUTOINCREMENTcolumn in your table to be able to use Android'sCursorAdapter, but you want to also make sure that the combination of two other columns is unique.In that case, I think that you want to use a
UNIQUEconstraint: