如何在C#中直接执行SQL查询？

Question

好的,我有一个旧的批处理文件,它完全符合我的需要.但是,如果没有新的管理,我们就不能再运行批处理文件了,所以我需要启动C#.

我正在使用Visual Studio C#,并且已经为我需要构建的应用程序设置了表单.(我正在学习)

这是我需要在C#中完成的(这是批量内容)

sqlcmd.exe -S .\PDATA_SQLEXPRESS -U sa -P 2BeChanged! -d PDATA_SQLEXPRESS  -s ; -W -w 100 -Q "SELECT tPatCulIntPatIDPk, tPatSFirstname, tPatSName, tPatDBirthday  FROM  [dbo].[TPatientRaw] WHERE tPatSName = '%name%' "

基本上它使用SQLCMD.exe已经存在的数据源调用PDATA_SQLExpress.
我已经搜索过并且已经接近但我仍然不知道从哪里开始.

Answer 1

要直接从C#中执行命令,您将使用SqlCommand类.

使用paramaterized SQL的快速示例代码(以避免注入攻击)可能如下所示:

string queryString = "SELECT tPatCulIntPatIDPk, tPatSFirstname, tPatSName, tPatDBirthday  FROM  [dbo].[TPatientRaw] WHERE tPatSName = @tPatSName";
string connectionString = "Server=.\PDATA_SQLEXPRESS;Database=;User Id=sa;Password=2BeChanged!;";

using (SqlConnection connection = new SqlConnection(connectionString))
{
    SqlCommand command = new SqlCommand(queryString, connection);
    command.Parameters.AddWithValue("@tPatSName", "Your-Parm-Value");
    connection.Open();
    SqlDataReader reader = command.ExecuteReader();
    try
    {
        while (reader.Read())
        {
            Console.WriteLine(String.Format("{0}, {1}",
            reader["tPatCulIntPatIDPk"], reader["tPatSFirstname"]));// etc
        }
    }
    finally
    {
        // Always call Close when done reading.
        reader.Close();
    }
}

Answer 2

这样的事情应该足够了,做你的批处理文件正在做的事情(将结果集转储为以分号分隔的文本到控制台):

// sqlcmd.exe
// -S .\PDATA_SQLEXPRESS
// -U sa
// -P 2BeChanged!
// -d PDATA_SQLEXPRESS
// -s ; -W -w 100
// -Q "SELECT tPatCulIntPatIDPk, tPatSFirstname, tPatSName, tPatDBirthday  FROM  [dbo].[TPatientRaw] WHERE tPatSName = '%name%' "

DataTable dt            = new DataTable() ;
int       rows_returned ;

const string credentials = @"Server=(localdb)\.\PDATA_SQLEXPRESS;Database=PDATA_SQLEXPRESS;User ID=sa;Password=2BeChanged!;" ;
const string sqlQuery = @"
  select tPatCulIntPatIDPk ,
         tPatSFirstname    ,
         tPatSName         ,
         tPatDBirthday
  from dbo.TPatientRaw
  where tPatSName = @patientSurname
  " ;

using ( SqlConnection connection = new SqlConnection(credentials) )
using ( SqlCommand    cmd        = connection.CreateCommand() )
using ( SqlDataAdapter sda       = new SqlDataAdapter( cmd ) )
{
  cmd.CommandText = sqlQuery ;
  cmd.CommandType = CommandType.Text ;
  connection.Open() ;
  rows_returned = sda.Fill(dt) ;
  connection.Close() ;
}

if ( dt.Rows.Count == 0 )
{
  // query returned no rows
}
else
{

  //write semicolon-delimited header
  string[] columnNames = dt.Columns
                           .Cast<DataColumn>()
                           .Select( c => c.ColumnName )
                           .ToArray()
                           ;
  string   header      = string.Join("," , columnNames) ;
  Console.WriteLine(header) ;

  // write each row
  foreach ( DataRow dr in dt.Rows )
  {

    // get each rows columns as a string (casting null into the nil (empty) string
    string[] values = new string[dt.Columns.Count];
    for ( int i = 0 ; i < dt.Columns.Count ; ++i )
    {
      values[i] = ((string) dr[i]) ?? "" ; // we'll treat nulls as the nil string for the nonce
    }

    // construct the string to be dumped, quoting each value and doubling any embedded quotes.
    string data = string.Join( ";" , values.Select( s => "\""+s.Replace("\"","\"\"")+"\"") ) ;
    Console.WriteLine(values);

  }

}