java - 如何删除 SQLite 数据库中的条目？

Question

我尝试创建 DeleteEvent()，但它不起作用。我需要在哪里更改代码？

这是一个 Android Studio java 代码。

public class DBStructure {enter code here
    public static final String DB_NAME =    "EVENTS_DB";
    public static final int DB_VERSION = 1;
    public static final String EVENT_TALE_NAME = "eventstable";
    public static final String EVENT = "event";
        public static final String TIME = "time";
    public static final String DATE = "date";
    public static final String MONTH = "month";
    public static final String YEAR = "year";

}

这是我的 DeleteEvent()

public void DeleteEvent(String event, String time, String date, String month, String year, SQLiteDatabase database){
    ContentValues contentValues = new ContentValues();
    contentValues.remove(DBStructure.EVENT);
    contentValues.remove(DBStructure.TIME);
    contentValues.remove(DBStructure.DATE);
    contentValues.remove(DBStructure.MONTH);
    contentValues.remove(DBStructure.YEAR);
    database.delete(DBStructure.EVENT_TALE_NAME, "?=? AND ?=?",
            new String[] {DBStructure.EVENT, event, DBStructure.TIME, time});
}

Answer 1

您不需要 ContentValues 来使用 delete() 方法:

public void DeleteEvent(String event, String time, String date, String month, String year, SQLiteDatabase database){
    database.delete(
        DBStructure.EVENT_TALE_NAME, 
        DBStructure.EVENT + " = ? AND " + DBStructure.TIME + " = ? AND " + DBStructure.DATE + " = ? AND " + 
        DBStructure.MONTH + " = ? AND " + DBStructure.YEAR + " = ?",
        new String[] {event, time, date, month, year}
    );
}

在第二个参数中，您构造 WHERE 子句，3d 以字符串数组的形式包含将替换占位符 ? 的参数。