Question

我正在尝试创建两个表（Users，Messages）。 users表，包含一个主键（RoomID），我将在Messages表中引用它。这是我试图运行的查询。

String CREATE_TABLE_MESSAGES = "CREATE TABLE " + Messages.TABLE  + "( "
                + "FOREIGN KEY(" + Messages.KEY_ROOMID  + ") REFERENCES "+ChatRooms.TABLE+"("+ChatRooms.KEY_ROOMID+"), "
                + Messages.MESSAGE+ " TEXT, "
                + Messages.SIDE+ " BOOLEAN, "
                + Messages.TYPE + " TEXT )";

但是，我一直遇到这个错误

09-28 18:45:14.803  14760-14789/lltest.mohsin.com.chattest E/SQLiteLog﹕ (1) near "FOREIGN": syntax error
09-28 18:45:14.807  14760-14789/lltest.mohsin.com.chattest W/System.err﹕ android.database.sqlite.SQLiteException: near "FOREIGN": syntax error (code 1): , while compiling: CREATE TABLE Messages( FOREIGN KEY(RoomID) REFERENCES ChatRooms(RoomID), Message TEXT, Side BOOLEAN, Type TEXT )
09-28 18:45:14.807  14760-14789/lltest.mohsin.com.chattest W/System.err﹕ at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
09-28 18:45:14.807  14760-14789/lltest.mohsin.com.chattest W/System.err﹕ at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:889)
09-28 18:45:14.807  14760-14789/lltest.mohsin.com.chattest W/System.err﹕ at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:500)
09-28 18:45:14.811  14760-14789/lltest.mohsin.com.chattest W/System.err﹕ at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)

我做错了什么？

Answer 1

您的TwoNumbers gcdNumbers = GCD(numbers.getNum1(), numbers.getNum2()); display(gcdNumbers); TwoNumbers lcmNumbers = LCM(numbers.getNum1(), numbers.getNum2()); display(lcmNumbers);定义应关注列定义。

请参阅SQLite手册中的示例：https://www.sqlite.org/foreignkeys.html

一旦这样做，它将再次失败，因为外键列（FOREIGN KEY）未定义。

在SQLite中使用引用

1 个答案: