修改数据库表中的项目

Question

我有这个SQLite数据库：

private static final String TAG = "DatabaseHelper";

private static final String TABLE_NAME = "people_table";
private static final String COL1 = "_id";
private static final String COL2 = "Hour";
private static final String COL3 = "Minutes";
private static final String COL4 = "On_Off";

我如何修改On_Off fom 1的值 - ＆gt; 0和0 - ＆gt; 1 Pseudocod：

public void OnAlarm()
{
    SQLiteDatabase db = this.getWritableDatabase();
    db.execSQL( "UPDATE " + TABLE_NAME + " SET " + COL4 + "=1 ");

}
public void OffAlarm()
{
    SQLiteDatabase db = this.getWritableDatabase();
    db.execSQL( "UPDATE " + TABLE_NAME + " SET " + COL4 + "=0 ");

}

Answer 1

... WHERE ... 什么？你错过了这个条件！

public void OnAlarm()
{
    // Change On_Off from 0 to 1
    SQLiteDatabase db = this.getWritableDatabase();
    db.execSQL( "UPDATE " + TABLE_NAME + " SET " + COL4 + " = 1 WHERE " + COL4 + " = 0");
}
public void OffAlarm()
{
    // Change On_Off from 1 to 0
    SQLiteDatabase db = this.getWritableDatabase();
    db.execSQL( "UPDATE " + TABLE_NAME + " SET " + COL4 + " = 0 WHERE " + COL4 + " = 1");

}