OleDbCommand cmd = new OleDbCommand("SELECT Stock FROM Products WHERE ID=" + ProductID + ";", conn); //run the database query
OleDbDataReader cusReader = cmd.ExecuteReader(); //read the result of the query
cusReader.Read();
ProductStock = (int)cusReader.GetValue(0);
cusReader.Close();
MessageBox.Show((ProductStock).ToString()); // checks that the form is being accessed and the SELECT query works
OleDbCommand cmd1 = new OleDbCommand("UPDATE Products SET Stock=" + (ProductStock - 1) + "WHERE ID= " + ProductID +";", conn);
try
{
if (cusReader.RecordsAffected > 0)
{
MessageBox.Show("no issue was experienced");
}
else
{
MessageBox.Show("An issue occured when decreasing stock");
}
cusReader.Close();
}
catch (Exception ex)
{
MessageBox.Show("An error occured in query.\n" + ex.Message);
}
更新查询返回“发生问题”消息。显示变量 Productstock 的消息框确实返回了正确的值。有人可以解释如何解决这个问题吗?
最佳答案
在 + "WHERE ID= "+
中的 WHERE
之前放置一个空格
此外,请确保您在 cmd1
上调用了 ExecuteNonQuery
。
关于c# - SQL 更新查询返回错误,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/39870068/