[1]
导出数据
namespace _05导出数据
{
class
Program
{
static
void Main(string[] args)
{
string str = "Data Source=xy-pc;Initial Catalog=MyItcast;Integrated Security=True";
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using (SqlConnection con=new
SqlConnection(str))
{
string sql = "select TClassId,TClassName,tclassdesc FROM TblClass";
using (SqlCommand cmd=new
SqlCommand(sql,con))
{
con.Open();
using (SqlDataReader sda=cmd.ExecuteReader())
{
if (sda.HasRows)
{
//把数据库中的文件写入到文本文件中去
using (StreamWriter sw=new
StreamWriter("1.txt"))
{
sw.WriteLine("{0},{1},{2}",sda.GetName(0),sda.GetName(1),sda.GetName(2));
while (sda.Read())
{
sw.WriteLine("{0},{1},{2}",sda["tclassid"],sda["tclassname"],sda["tclassdesc"]);
}
}
}
}
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}
}
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Console.WriteLine("搞定了");
Console.ReadKey();
}
}
}
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[2]
namespace _06导入数据
{
class
Program
{
static
void Main(string[] args)
{
using (StreamReader sr=new
StreamReader("1.txt"))
{
string line = sr.ReadLine();//读取第一行内容
string str = "Data Source=xy-pc;Initial Catalog=MyItcast;Integrated Security=True";
using (SqlConnection con=new
SqlConnection(str))
{
string sql = "insert INTO TblClass(TClassName,TClassDesc)VALUES(@TClassName,@TClassDesc)";
using (SqlCommand cmd=new
SqlCommand(sql,con))
{
con.Open();//打开数据库
//设置每个参数的类型
SqlParameter[] param =
{
new
SqlParameter("@TClassName", System.Data.SqlDbType.NVarChar),
new
SqlParameter("@TClassDesc", System.Data.SqlDbType.NVarChar)
};
cmd.Parameters.AddRange(param);
while ((line=sr.ReadLine())!=null)
{
string[]txts= line.Split(‘,‘);
string className = txts[1];
string classDesc = txts[2];
//给数组中的每个参数进行赋值
param[0].Value = className;
param[1].Value = classDesc;
cmd.ExecuteNonQuery();
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}//end while
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}//end using
}//end using
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}//end 流
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Console.WriteLine( "执行完了");
Console.ReadKey();
}
}
}
[3]App.config
<?xml
version="1.0"
encoding="utf-8" ?>
<configuration>
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<connectionStrings>
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<add
connectionString="Data Source=xy-pc;Initial Catalog=MyItcast;Integrated Security=True"
name="strCon" />
</connectionStrings>
</configuration>
[4]
public
class
SQLHelper
{
private
static
readonly
string str = ConfigurationManager.ConnectionStrings["strCon"].ConnectionString;
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///
<summary>
///
增删改方法
///
</summary>
///
<param name="sql">传sql语句</param>
///
<param name="param">如果sql语句带参数,则传参数,如果没有参数则不用传</param>
///
<returns></returns>
public
static
int ExeCuteNonQuery(string sql,params
SqlParameter[] param)
{
using (SqlConnection con=new
SqlConnection(str))
{
using (SqlCommand cmd=new
SqlCommand(sql,con))
{
con.Open();
if (param!=null)
{
cmd.Parameters.AddRange(param);//把用户传过来的参数给cmdparameters了
}
return cmd.ExecuteNonQuery();//完事
}
}
}
public
static
object ExecuteScalar(string sql,params
SqlParameter[]param)
{
using (SqlConnection con=new
SqlConnection(str))
{
using (SqlCommand cmd=new
SqlCommand(sql,con))
{
con.Open();
if (param!=null)
{
cmd.Parameters.AddRange(param);
}
return cmd.ExecuteScalar();
}
}
}
public
static
SqlDataReader ExecuteReader(string sql,params
SqlParameter[]param)
{
SqlConnection con = new
SqlConnection(str);
using (SqlCommand cmd=new
SqlCommand(sql,con))
{
if (param != null)
{
cmd.Parameters.AddRange(param);
}
try
{
con.Open();
return cmd.ExecuteReader(System.Data.CommandBehavior.CloseConnection);
}
catch(Exception ex)
{
con.Close();
con.Dispose();
throw ex;//有可能会出现异常,但是不确定异常是什么
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}
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}
}
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}
}
[5]sql参数
string sql = "insert into tblstudent(tsname,tsgender,tsage,tclassid)values(@name,@gender,@age,@classid)";
SqlParameter[] param =
{
new
SqlParameter("@name",name),
new
SqlParameter("@gender",gender),
new
SqlParameter("@age",age),
new
SqlParameter("@classid",classid)
};