小编Sou*_*tra的帖子

我有以下代码：

[Flags()]
public enum Foo
{
    Unknown = 0x00,
    A = 0x01,
    B = 0x02,
    C = 0x04,
    D = 0x08,
}

public static class Extensions
{
    public static List<Foo> AsList(this Foo types)
    {
        List<Foo> list = new List<Foo>();
        foreach(Foo sT in Enum.GetValues(typeof(Foo)))
        {
            if ((sT & types) == sT) list.Add(sT);
        }
        return list;
    }

}

class Program
{
    static void Main(string[] args)
    {
        Foo foo1 = Foo.A | Foo.B | Foo.C;
        Foo foo2 = Foo.C | Foo.B;

        Foo firstInfoo1 …

我有以下代码:

//Interface defining a Change method
internal interface IChangeBoxedPoint
{
    void Change(Int32 x, Int32 y);
}

internal struct Point : IChangeBoxedPoint 
{
    private Int32 m_x, m_y;

    public Point(Int32 x, Int32 y)
    {
        m_x = x;
        m_y = y;
    }

    public void Change(Int32 x, Int32 y)
    {
        m_x = x; m_y = y;
    }

    public override string ToString()
    {
        return String.Format("({0}, {1})", m_x.ToString(), m_y.ToString());
    }
}

public class Program
{
    static void Main(string[] args)
    {
        Point p = new Point(1, 1); …

我知道REPLACE并且ON DUPLICATE UPDATE,如果我的员工存在,我想插入的东西,如果确实如此,则根据条件更新一些列.

例如:My Table列

Id(Auto Generated), EmpId, EmpName, Salary, Version
12                  ABW72  John     1000    100

EmpId 不是主键,但有一个 Unique Index

现在,如果ABW72不存在,一INSERT会做,UPDATE如果存在EmpId = ABW72,只有当version is > 20.此版本是存储在DB中的版本.如何在MySql中做到这一点.

我们在应用程序方面尝试过这样的事情:

Step 1: Select with a lock on EmpId=ABW72. A lock would be taken if it exists.
Step 2: If Step1 returned 0 records, Insert Ignore OR Insert
Step 2: If Step1 returned 1 record, just update based on the …