如何使用旧值更新行而不在SQLite中进行查询？

Question

I need to update certain cells of db table. I have a function that updates certain value, here it is:

public final int updateBpm(long millisOfDay, float bpmValue, int trngTime, int id) {
mDb.execSQL("UPDATE " + TABLE_BPM_STAT +
  " SET " + BPM_COLUMN + " = (" + BPM_COLUMN + " * " + TIME_COLUMN + " + "
  + bpmValue + " * " + trngTime + ") / (" + TIME_COLUMN + " + " + trngTime + "),"
  + TIME_COLUMN + " = " + TIME_COLUMN + " + " + trngTime + ", "
 + " WHERE " + DATE_COLUMN + " = " + millisOfDay +
  " AND " + ID_COLUMN + " = " + id);
// here if affected rows == 0, I should insert this value
}

I've looked at db.update(String table, ContentValues values, String whereClause, String[] whereArgs) . It returns affected rows, but how can I update certain cell using another cells of the same row, without replacing it?

final ContentValues updateValues = new ContentValues();
updateValues.put(BPM_COLUMN, ..); // I don't need replace it, I need to use old data from the table to construct a new one
updateValues.put(TIME_COLUMN, ..);
mDb.update(STAT_TABLE, updateValues, ID_COLUMN + " = ?", new String[]{String.valueOf(id)});

How can I do it using update method, but without query before it?

Answer 1

The update() method supports only literal valued. To be able to use old values for computations, you have to keep using execSQL() .