java - 创建唯一的复合列的语法-Android SQLiteOpenHelper

我的onCreate中有此SQLiteOpenHelper方法
类，我想在这两列（复合唯一列）上添加唯一约束：


SongContract.SongEntry.COLUMN_TITLE
SongContract.SongEntry.COLUMN_RELEASEDATE


但我收到一个错误：


  无法解析方法UNIQUE


这是我的代码：

public void onCreate(SQLiteDatabase db) {
    final String SQL_CREATE_SONG_TABLE = "CREATE TABLE " + SongContract.SongEntry.TABLE_SONG + " (" +
        SongContract.SongEntry._ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
        SongContract.SongEntry.COLUMN_TITLE + " TEXT NOT NULL, " +
        SongContract.SongEntry.COLUMN_RELEASEDATE + " INTEGER, " +
        UNIQUE(SongContract.SongEntry.COLUMN_TITLE, SongContract.SongEntry.COLUMN_RELEASEDATE) +
        SongContract.SongEntry.COLUMN_RATING + " TEXT);";

    db.execSQL(SQL_CREATE_SONG_TABLE);
}

什么是实现我的目标的正确语法？

最佳答案

我在玩sqllite之后发现了正确的语法：

最后的字符串SQL_CREATE_SONG_TABLE =“ CREATE TABLE” + SongContract.SongEntry.TABLE_SONG +“（” +
            SongContract.SongEntry._ID +“整数主键自动递增，” +
            SongContract.SongEntry.COLUMN_TITLE +“ TEXT NOT NULL，” +
            SongContract.SongEntry.COLUMN_RELEASEDATE +“ INTEGER NOT NULL，” +
            SongContract.SongEntry.COLUMN_RATING +“ TEXT，” +“ UNIQUE” +“（” +
            SongContract.SongEntry.COLUMN_TITLE +“，” + SongContract.SongEntry.COLUMN_RELEASEDATE +“）” +“）;”;