1 SQL事务
    sql事务是使用SQL server自身的事务：在存储过程中直接使用Begin Tran，Rollback Tran，Commit Tran实现事务：
优点：执行效率最佳
限制：事务上下文仅在数据库中调用，难以实现复杂的业务逻辑。
Demo：（所有demo,都以SQL Server自带的Northwind数据的表Region为例）
带事务的储存过程:
CREATE PROCEDURE dbo.SPTransaction
     (
    @UpdateID int,
      @UpdateValue nchar(50),
    @InsertID int,
    @InsertValue nchar(50)
     )
AS
begin Tran
Update Region  Set RegionDescription=@UpdateValue where RegionID=@UpdateID
insert into Region Values (@InsertID,@InsertValue)
declare @RegionError int
select @RegionError=@@error
if(@RegionError=0)
COMMIT Tran
else
ROLLBACK Tran
GO
执行带事务的储存过程:
/// <summary>
        /// SQL事务:
        /// </summary>
        public void SQLTran()
        {
             SqlConnection conn = new SqlConnection("Data Source=127.0.0.1;Initial Catalog=Northwind;Persist Security Info=True;User ID=sa;Password=123;");
             SqlCommand cmd = new SqlCommand();
             cmd.CommandText = "SPTransaction";
             cmd.CommandType = CommandType.StoredProcedure;
             cmd.Connection = conn;
             conn.Open();
             SqlParameter[] paras= new SqlParameter[]{
                                        new SqlParameter ("@UpdateID",SqlDbType.Int,32),
                                        new SqlParameter ("@UpdateValue",SqlDbType .NChar,50),
                                        new SqlParameter ("@InsertID",SqlDbType.Int ,32),
                                        new SqlParameter ("@InsertValue",SqlDbType.NChar ,50)};
             paras[0].Value = "2";
             paras[1].Value = "Update Value1";
             paras[2].Value = "6";
             paras[3].Value = "Insert Value1";
            foreach (SqlParameter para in paras )
            {
                 cmd.Parameters.Add(para);
             }
             cmd.ExecuteNonQuery();   
         }
2 ADO.net事务
   Ado.net事务可能是大家一般都用的
优点：简单，效率和数据库事务差不多。
缺点：事务不能跨数据库，只能在一个数据库连接上。如果是两个数据库上就不能使用该事务了。
Demo:
         /// <summary>
        /// 一般的ADO.net 事务
        /// </summary>
        public void ADONetTran1()
        {
             SqlConnection conn = new SqlConnection("Data Source=127.0.0.1;Initial Catalog=Northwind;Persist Security Info=True;User ID=sa;Password=123;");
             SqlCommand cmd = new SqlCommand();
            try
            {
                 cmd.CommandText = "Update Region Set RegionDescription=@UpdateValue where RegionID=@UpdateID";
                 cmd.CommandType = CommandType.Text;
                 cmd.Connection = conn;
                 conn.Open();
                 SqlParameter[] paras = new SqlParameter[]{
                                        new SqlParameter ("@UpdateID",SqlDbType.Int,32),
                                        new SqlParameter ("@UpdateValue",SqlDbType .NChar,50)};
                 paras[0].Value = "2";
                 paras[1].Value = "Update Value12";

foreach (SqlParameter para in paras)
                {
                     cmd.Parameters.Add(para);
                 }
                //开始事务
                 cmd.Transaction = conn.BeginTransaction();
                 cmd.ExecuteNonQuery();

cmd.CommandText = "insert into Region values(@InsertID,@InsertValue)";
                 cmd.CommandType = CommandType.Text;

paras = new SqlParameter[]{
                                        new SqlParameter ("@InsertID",SqlDbType.Int ,32),
                                        new SqlParameter ("@InsertValue",SqlDbType.NChar ,50)};
                 paras[0].Value = "7";
                 paras[1].Value = "Insert Value";
                 cmd.Parameters.Clear();
                foreach (SqlParameter para in paras)
                {
                     cmd.Parameters.Add(para);
                 }                
                 cmd.ExecuteNonQuery();
                //提交事务
                 cmd.Transaction.Commit();
             }
            catch
            {
                //回滚事务
                 cmd.Transaction.Rollback();
                throw;
             }
            finally
            {
                 conn.Close();
             }
         }