万能的SQLHelper帮助类

/// <summary>
/// 数据库帮助类
/// </summary>
public class SQLHelper
{
private static string connStr = "server=.;database=***;uid=**;pwd=***";

//定义对象
private static SqlConnection conn = null;
private static SqlCommand cmd = null;
private static SqlDataAdapter sda = null;
private static DataSet ds = null;

/// <summary>
/// 查询多行多列
/// </summary>
public static DataSet Search(string sql, params SqlParameter[] parameters)
{
try
{
using (conn = new SqlConnection(connStr))
{
conn.Open();
cmd = new SqlCommand(sql, conn);
foreach (SqlParameter p in parameters)
{
cmd.Parameters.Add(p);
}
sda = new SqlDataAdapter(cmd);
ds = new DataSet();
sda.Fill(ds);

return ds;
}
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
finally
{
conn.Close();
}
}

/// <summary>
/// 查询单行单列
/// </summary>
public static object ExecuteScalar(string sql, params SqlParameter[] parameters)
{
try
{
using (conn = new SqlConnection(connStr))
{
conn.Open();
cmd = new SqlCommand(sql, conn);
foreach (SqlParameter p in parameters)
{
cmd.Parameters.Add(p);
}
object obj = cmd.ExecuteScalar();

return obj;
}
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
finally
{
conn.Close();
}
}

/// <summary>
/// 查询单行单列(增删改查)
/// </summary>
public static int ExecuteNonQuery(string sql, params SqlParameter[] parameters)
{
try
{
using (conn = new SqlConnection(connStr))
{
conn.Open();
cmd = new SqlCommand(sql, conn);
foreach (SqlParameter p in parameters)
{
cmd.Parameters.Add(p);
}
int row = cmd.ExecuteNonQuery();

return row;
}
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
finally
{
conn.Close();
}
}
}