[英]Syntax to create unique composite column - Android SQLiteOpenHelper
我在SQLiteOpenHelper
類中具有此onCreate
方法,並且我想在這兩列(復合唯一列)上添加唯一約束:
SongContract.SongEntry.COLUMN_TITLE
SongContract.SongEntry.COLUMN_RELEASEDATE
但我收到一個錯誤:
無法解析方法UNIQUE
這是我的代碼:
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);
}
什么是實現我的目標的正確語法?
我在玩sqllite之后發現了正確的語法:
final String SQL_CREATE_SONG_TABLE =“ CREATE TABLE” + SongContract.SongEntry.TABLE_SONG +“(” + SongContract.SongEntry._ID +“整數主鍵自動增加,” + SongContract.SongEntry.COLUMN_TITLE +“文本不為空,” + SongContractS。 COLUMN_RELEASEDATE +“ INTEGER NOT NULL,” + SongContract.SongEntry.COLUMN_RATING +“ TEXT,” +“ UNIQUE” +“(” + SongContract.SongEntry.COLUMN_TITLE +“,” + SongContract.SongEntry.COLUMN_RELEASEDATE +“)” +“) ;“;
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