[ActiveRecord] 之二：常用方法

看下面的例子

[ActiveRecord("Users")]
public class User : ActiveRecordBase
{
  public User() {}

  public User(string name) : this()
  {
    this.name = name;
  }

  private int id;

  [PrimaryKey(PrimaryKeyType.Identity)]
  public int Id
  {
    get { return id; }
    set { id = value; }
  }

  private string name;

  [Property(Unique=true)]
  public string Name
  {
    get { return name; }
    set { name = value; }
  }
}

一般情况下，系统代码生成工具(Castle.ActiveRecord.Generator.exe)会自动生成以下几个静态方法。

public static void DeleteAll()
{
  ActiveRecordBase.DeleteAll(typeof(User));
}
 
public static User[] FindAll()
{
  return ((User[])(ActiveRecordBase.FindAll(typeof(User))));
}
 
public static User Find(int Id)
{
  return ((User)(ActiveRecordBase.FindByPrimaryKey(typeof(User), Id)));
}

很显然这几个方法并不能满足需要，接下来我们补充几个。

public static User Find(string name)
{
  ScalarQuery query = new ScalarQuery(typeof(User), "from User user where user.Name=?", name);
  return ExecuteQuery(query) as User;
}

public static void Delete2()
{
  DeleteAll(typeof(User), "id > 5");
}

public static string GetName(int id)
{
  ScalarQuery query = new ScalarQuery(typeof(User), "select user.Name from User user where user.Id=?", id);
  return ExecuteQuery(query) as string;
}

public static User[] FindAll2(int id)
{
  SimpleQuery query = new SimpleQuery(typeof(User), "from User user where user.Id < ?", id);
  return ExecuteQuery(query) as User[];
}

需要注意的是ActiveRecord(NHibernate)删除记录时，并不是使用单个SQL语句批量删除，而是使用主键依次删除每条记录。晕~~~ 要是删除1000万条记录就得执行1000万条Delete SQL语句。晕~~~~~~~