关于Dapper的使用笔记1

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1、Execute a query and map the results to a strongly typed List

Note: all extension methods assume the connection is already open, they will fail if the connection is closed.

public static IEnumerable<T> Query<T>(this IDbConnection cnn, string sql, object param = null, SqlTransaction transaction = null, bool buffered = true)

Example usage:

public class Dog

{

    public int? Age { get; set; }

    public Guid Id { get; set; }

    public string Name { get; set; }

    public float? Weight { get; set; }

 

    public int IgnoredProperty { get { return 1; } }

}            

 

var guid = Guid.NewGuid();

var dog = connection.Query<Dog>("select Age = @Age, Id = @Id", new { Age = (int?)null, Id = guid });

 

dog.Count().IsEqualTo(1);

dog.First().Age.IsNull();

dog.First().Id.IsEqualTo(guid);

 

 

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2、Execute a query and map it to a list of dynamic objects

public static IEnumerable<dynamic> Query (this IDbConnection cnn, string sql, object param = null, SqlTransaction transaction = null, bool buffered = true)

This method will execute SQL and return a dynamic list.

Example usage:

var rows = connection.Query("select 1 A, 2 B union all select 3, 4");

 

((int)rows[0].A).IsEqualTo(1);

((int)rows[0].B).IsEqualTo(2);

((int)rows[1].A).IsEqualTo(3);

((int)rows[1].B).IsEqualTo(4);

 

DbConnection con = this.GetConnection();

return con.Query<t_So>("select * from dbo.t_so").ToList();//可以像上面一样，支持参数化查询，直接简单！

 

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3、Execute a Command that returns no results

public static int Execute(this IDbConnection cnn, string sql, object param = null, SqlTransaction transaction = null)

Example usage:

connection.Execute(@"

  set nocount on 

  create table #t(i int) 

  set nocount off 

  insert #t 

  select @a a union all select @b 

  set nocount on 

  drop table #t", new {a=1, b=2 })

   .IsEqualTo(2);

向数据据插入对象：

t_So so = new t_So();

so.KeySeq = Guid.NewGuid();

so.SoNo = this.sSoNo.Text;

so.SoDate = GetValue.GetDateTime(this.sSoDate.Text);

so.CustomerName = this.sCustomerName.Text;

so.Remark = this.sRemark.Text;

 

string strSQL = @"INSERT INTO dbo.t_so(KeySeq,SoNo,SoDate,CustomerName,Remark)VALUES(@KeySeq,@SoNo,@SoDate,@CustomerName,@Remark)";

DbConnection con = this.GetConnection();

//con.Execute(strSQL, new {KeySeq = so.KeySeq, SoNo = so.SoNo, SoDate = so.SoDate, CustomerName = so.CustomerName, Remark = so.Remark});

con.Execute(strSQL, so);

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4、Execute a Command multiple times The same signature also allows you to conveniently and efficiently execute a command multiple times (for example to bulk-load data) Example usage:

connection.Execute(@"insert MyTable(colA, colB) values (@a, @b)",

    new[] { new { a=1, b=1 }, new { a=2, b=2 }, new { a=3, b=3 } }

  ).IsEqualTo(3); // 3 rows inserted: "1,1", "2,2" and "3,3"

This works for any parameter that implements IEnumerable for some T. 这个可以批量插入的，不错!