Dapper官方教程翻译11：Dapper方法之异步方法、缓存、事务、存储过程

1.dapper包含异步方法

 

• ExecuteAsync
• QueryAsync
• QueryFirstAsync
• QueryFirstOrDefaultAsync
• QuerySingleAsync
• QuerySingleOrDefaultAsync
• QueryMultipleAsync

使用方法类似于同步方法。

 

2.缓存

 

dapper查询方法默认开启缓存，这样会加快第二次以后的查询速度，但是对于查询数据量比较巨大的结果，比如select * from xx

去掉缓存可以减轻内存的压力。

string sql = "SELECT * FROM OrderDetails;";

using (var connection = new SqlCeConnection("Data Source=SqlCe_W3Schools.sdf"))
{
	var orderDetails = connection.Query<OrderDetail>(sql, buffered: false).ToList();

	FiddleHelper.WriteTable(orderDetails.Take(10));
}

3.事务

 

1.开启事务

string sql = "INSERT INTO Customers (CustomerName) Values (@CustomerName);";

using (var connection = new SqlCeConnection("Data Source=SqlCe_W3Schools.sdf"))
{
	connection.Open();
	
	using (var transaction = connection.BeginTransaction())
	{
		var affectedRows = connection.Execute(sql, new {CustomerName = "Mark"}, transaction: transaction);
		
		transaction.Commit();
		
		Console.WriteLine(affectedRows);
	}
}

2.开启事务范围

// using System.Transactions;

using (var transaction = new TransactionScope())
{
	var sql = "Invoice_Insert";

	using (var connection = My.ConnectionFactory())
	{
		connection.Open();

		var affectedRows = connection.Execute(sql,
			new {Kind = InvoiceKind.WebInvoice, Code = "Single_Insert_1"},
			commandType: CommandType.StoredProcedure);
	}

	transaction.Complete();
}

 

4.执行存储过程

 

一次执行：

var sql = "Invoice_Insert";

using (var connection = My.ConnectionFactory())
{
	connection.Open();

	var affectedRows = connection.Execute(sql,
		new {Kind = InvoiceKind.WebInvoice, Code = "Single_Insert_1"},
		commandType: CommandType.StoredProcedure);

	My.Result.Show(affectedRows);
}

批量执行：

var sql = "Invoice_Insert";

using (var connection = My.ConnectionFactory())
{
	connection.Open();

	var affectedRows = connection.Execute(sql,
		new[]
		{
			new {Kind = InvoiceKind.WebInvoice, Code = "Many_Insert_1"},
			new {Kind = InvoiceKind.WebInvoice, Code = "Many_Insert_2"},
			new {Kind = InvoiceKind.StoreInvoice, Code = "Many_Insert_3"}
		},
		commandType: CommandType.StoredProcedure
	);

	My.Result.Show(affectedRows);
}