新手写的操作SQL数据库代码，运行通过，但性能不好，请帮忙改正？

[feisfans]

            string strConnection = "";
            strConnection = ConfigurationSettings.AppSettings["connString"];//连接字符串
            SqlConnection objConnection = new SqlConnection(strConnection); 
            SqlCommand cmd = new SqlCommand();
            cmd.Parameters.Clear();
            cmd.CommandText = "News_S";//查询新闻
            cmd.Parameters.Add("@id", SqlDbType.Int).Value = id;//传递新闻ID参数
            cmd.CommandType = CommandType.StoredProcedure;
            cmd.Connection = objConnection;
                cmd.Connection.Open();
                SqlDataReader dr = cmd.ExecuteReader();
                try
                { 
                if (dr.Read() == false)
                {
                //如果没读到记录就什么都不做
                }
                else
                { 
                    string strID=dr["ID"].ToString();//读取新闻ID
                    string author = dr["author"].ToString();//读取作者信息
                    string source = dr["source"].ToString();//读取来源
                    string title = dr["title"].ToString();//读取文章标题
                    string content = dr["content"].ToString();//读取文章内容
                    string newsurl;
                    newsurl="show.aspx?ID="+strID;
                }
                dr.Close(); //关闭记录集
            }
            catch (SqlException ex)
            {
                Response.Write(ex.ToString());//输出异常信息
            }

            finally
            {
                cmd.Connection.Close();//关闭连接
                objConnection.Close();//关闭连接，这里好像前后关闭的都是objconnection，用一个就好了，是不是需要加上cmd.Dispose();objConnection.Dispose();？疑惑…
            }
        }

[TimZhuFaith]

没有什么大问题。。

[堆代码的爱因斯坦]

SqlConnection objConnection = new SqlConnection(strConnection);
用using包起来！

[子夜__]

string strID=dr["ID"].ToString();//读取新闻ID
string author = dr["author"].ToString();//读取作者信息
string source = dr["source"].ToString();//读取来源
string title = dr["title"].ToString();//读取文章标题
string content = dr["content"].ToString();//读取文章内容
string newsurl;
newsurl="show.aspx?ID="+strID;


这些东西应该改为实体

SqlConnection con=new SqlConnection("server=.;database=数据库名称;uid=数据库用户名;pwd=数据库密码");
con.open()
string sql="select * from 指定表";//或者存储过程名字
SqlDataAdapter ada=new SqlDataAdapter(sql,con);
DataSet ds=new DataSet();
ada.Fill(ds);
con.Close;


连接字符串最好配置在webconfig中

数据库操作可以采用微软的 SQLHELPER 都封装好了

可以直接用。。

[wuyq11]

LINQ TO SQL
public abstract class DbHelperSQL
{
//数据库连接字符串(web.config来配置)
//<add key="ConnectionString" value="server=127.0.0.1;database=DATABASE;uid=sa;pwd=" />
protected static string connectionString = ConfigurationSettings.AppSettings["ConnectionString"];
public DbHelperSQL()
{
}

#region 公用方法

public static int GetMaxID(string FieldName,string TableName)
{
string strsql = "select max(" + FieldName + ")+1 from " + TableName;
object obj = GetSingle(strsql);
if (obj == null)
{
return 1;
}
else
{
return int.Parse(obj.ToString());
}
}
public static bool Exists(string strSql, params SqlParameter[] cmdParms)
{
object obj = GetSingle(strSql, cmdParms);
int cmdresult;
if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
{
cmdresult = 0;
}
else
{
cmdresult = int.Parse(obj.ToString());
}
if (cmdresult == 0)
{
return false;
}
else
{
return true;
}
}
#endregion
#region 执行简单SQL语句

/// <summary>
/// 执行SQL语句，返回影响的记录数
/// </summary>
/// <param name="SQLString">SQL语句</param>
/// <returns>影响的记录数</returns>
public static int ExecuteSql(string SQLString)
{
using (SqlConnection connection = new SqlConnection(connectionString))
{
using (SqlCommand cmd = new SqlCommand(SQLString,connection))
{
try
{
connection.Open();
int rows=cmd.ExecuteNonQuery();
return rows;
}
catch(System.Data.SqlClient.SqlException E)
{
connection.Close();
throw new Exception(E.Message);
}
}
}
}
/// <summary>
/// 执行一条计算查询结果语句，返回查询结果（object）。
/// </summary>
/// <param name="SQLString">计算查询结果语句</param>
/// <returns>查询结果（object）</returns>
public static object GetSingle(string SQLString)
{
using (SqlConnection connection = new SqlConnection(connectionString))
{
using(SqlCommand cmd = new SqlCommand(SQLString,connection))
{
try
{
connection.Open();
object obj = cmd.ExecuteScalar();
if((Object.Equals(obj,null))||(Object.Equals(obj,System.DBNull.Value)))
{
return null;
}
else
{
return obj;
}
}
catch(System.Data.SqlClient.SqlException e)
{
connection.Close();
throw new Exception(e.Message);
}
}
}
}
/// <summary>
/// 执行查询语句，返回SqlDataReader
/// </summary>
/// <param name="strSQL">查询语句</param>
/// <returns>SqlDataReader</returns>
public static SqlDataReader ExecuteReader(string strSQL)
{
SqlConnection connection = new SqlConnection(connectionString);
SqlCommand cmd = new SqlCommand(strSQL,connection);
try
{
connection.Open();
SqlDataReader myReader = cmd.ExecuteReader();
return myReader;
}
catch(System.Data.SqlClient.SqlException e)
{
throw new Exception(e.Message);
}

}
/// <summary>
/// 执行查询语句，返回DataSet
/// </summary>
/// <param name="SQLString">查询语句</param>
/// <returns>DataSet</returns>
public static DataSet Query(string SQLString)
{
using (SqlConnection connection = new SqlConnection(connectionString))
{
DataSet ds = new DataSet();
try
{
connection.Open();
SqlDataAdapter command = new SqlDataAdapter(SQLString,connection);
command.Fill(ds,"ds");
}
catch(System.Data.SqlClient.SqlException ex)
{
throw new Exception(ex.Message);
}
return ds;
}
}


#endregion
}

[wuyq11]

public abstract class SqlHelper {
//Database connection strings
public static readonly string ConnectionStringLocalTransaction = ConfigurationManager.ConnectionStrings["SQLConnString1"].ConnectionString;

private static Hashtable parmCache = Hashtable.Synchronized(new Hashtable());

public static int ExecuteNonQuery(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters) {

SqlCommand cmd = new SqlCommand();

using (SqlConnection conn = new SqlConnection(connectionString)) {
PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return val;
}
}
public static int ExecuteNonQuery(SqlConnection connection, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters) {

SqlCommand cmd = new SqlCommand();

PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return val;
}
public static int ExecuteNonQuery(SqlTransaction trans, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters) {
SqlCommand cmd = new SqlCommand();
PrepareCommand(cmd, trans.Connection, trans, cmdType, cmdText, commandParameters);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return val;
}

public static SqlDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters) {
SqlCommand cmd = new SqlCommand();
SqlConnection conn = new SqlConnection(connectionString);
try {
PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
cmd.Parameters.Clear();
return rdr;
}
catch {
conn.Close();
throw;
}
}

public static object ExecuteScalar(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters) {
SqlCommand cmd = new SqlCommand();

using (SqlConnection connection = new SqlConnection(connectionString)) {
PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
object val = cmd.ExecuteScalar();
cmd.Parameters.Clear();
return val;
}
}

public static object ExecuteScalar(SqlConnection connection, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters) {

SqlCommand cmd = new SqlCommand();

PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
object val = cmd.ExecuteScalar();
cmd.Parameters.Clear();
return val;
}

public static void CacheParameters(string cacheKey, params SqlParameter[] commandParameters) {
parmCache[cacheKey] = commandParameters;
}

public static SqlParameter[] GetCachedParameters(string cacheKey) {
SqlParameter[] cachedParms = (SqlParameter[])parmCache[cacheKey];

if (cachedParms == null)
return null;

SqlParameter[] clonedParms = new SqlParameter[cachedParms.Length];

for (int i = 0, j = cachedParms.Length; i < j; i++)
clonedParms[i] = (SqlParameter)((ICloneable)cachedParms[i]).Clone();

return clonedParms;
}


private static void PrepareCommand(SqlCommand cmd, SqlConnection conn, SqlTransaction trans, CommandType cmdType, string cmdText, SqlParameter[] cmdParms) {

if (conn.State != ConnectionState.Open)
conn.Open();

cmd.Connection = conn;
cmd.CommandText = cmdText;

if (trans != null)
cmd.Transaction = trans;

cmd.CommandType = cmdType;

if (cmdParms != null) {
foreach (SqlParameter parm in cmdParms)
cmd.Parameters.Add(parm);
}
}
}

[vrhero]

就一句而已，哪有什么性能问题...除非，你把这一大段包在循环里...

[子夜__]

webconfig

可以这样配置 连级字符串

＜connectionStrings＞
＜add name="Northwind" connectionString="Server=localhost;
Integrated Security=True;Database=Northwind;Persist Security Info=True"
providerName="System.Data.SqlClient" /＞
＜/connectionStrings＞

后台取的时候就用、

string connectionString =ConfigurationManager.ConnectionStrings["Northwind"].ConnectionString;

另赋 SQLHELPER使用

[dalmeeme]

没有太大问题，主要是开头的地方，稍嫌繁冗，可以再写得简练一点。

[机器人]

你用的是存储过程，存储过程也没贴出来。咋分析你的性能问题？

[我说我行就是行]

你这代码还行，如果修改的话，使用Linq语句，或者加个using{这是你那段代码}，

[笑道江湖情]

代码还是要规范点

if(dr.Read() == false){//什么都不做} --》 if(dr.Read()){//要做的事情}

如果参数不是很多的话，可以放到构造函数就尽量放构造函数中

类似Connection这样的代码， 可以使用using{}域

代码要适当的精简