www.pudn.com > AlumniWeb.rar > SQLHelper.cs
using System;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Collections;
namespace DBHelper
{
///
/// Summary description for SQLHelper.
///
public abstract class SQLHelper
{
///
/// Execute a SqlCommand (that returns no resultset) against the database specified in the connection string
/// using the provided parameters.
///
///
/// e.g.:
/// int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
///
/// a valid connection string for a SqlConnection
/// the CommandType (stored procedure, text, etc.)
/// the stored procedure name or T-SQL command
/// an array of SqlParamters used to execute the command
/// an int representing the number of rows affected by the command
public static int ExecuteNonQuery(string connString, CommandType cmdType, string cmdText, params SqlParameter[] cmdParms)
{
///定义数据库的SQLCommand
SqlCommand cmd = new SqlCommand();
///创建数据库的Connection
using (SqlConnection conn = new SqlConnection(connString))
{
///准备数据库参数
PrepareCommand(cmd, conn, null, cmdType, cmdText, cmdParms);
//执行数据库操作
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return val;
}
}
///
/// Execute a SqlCommand (that returns no resultset) against an existing database connection
/// using the provided parameters.
///
///
/// e.g.:
/// int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
///
/// an existing database connection
/// the CommandType (stored procedure, text, etc.)
/// the stored procedure name or T-SQL command
/// an array of SqlParamters used to execute the command
/// an int representing the number of rows affected by the command
public static int ExecuteNonQuery(SqlConnection conn, CommandType cmdType, string cmdText, params SqlParameter[] cmdParms)
{
SqlCommand cmd = new SqlCommand();
PrepareCommand(cmd, conn, null, cmdType, cmdText, cmdParms);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return val;
}
///
/// Execute a SqlCommand (that returns no resultset) using an existing SQL Transaction
/// using the provided parameters.
///
///
/// e.g.:
/// int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
///
/// an existing sql transaction
/// the CommandType (stored procedure, text, etc.)
/// the stored procedure name or T-SQL command
/// an array of SqlParamters used to execute the command
/// an int representing the number of rows affected by the command
public static int ExecuteNonQuery(SqlTransaction trans, CommandType cmdType, string cmdText, params SqlParameter[] cmdParms)
{
SqlCommand cmd = new SqlCommand();
PrepareCommand(cmd, trans.Connection, trans, cmdType, cmdText, cmdParms);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return val;
}
///
/// Execute a SqlCommand that returns a resultset against the database specified in the connection string
/// using the provided parameters.
///
///
/// e.g.:
/// SqlDataReader r = ExecuteReader(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
///
/// a valid connection string for a SqlConnection
/// the CommandType (stored procedure, text, etc.)
/// the stored procedure name or T-SQL command
/// an array of SqlParamters used to execute the command
/// A SqlDataReader containing the results
public static SqlDataReader ExecuteReader(string connString, CommandType cmdType, string cmdText, params SqlParameter[] cmdParms)
{
SqlCommand cmd = new SqlCommand();
SqlConnection conn = new SqlConnection(connString);
// we use a try/catch here because if the method throws an exception we want to
// close the connection throw code, because no datareader will exist, hence the
// commandBehaviour.CloseConnection will not work
try
{
PrepareCommand(cmd, conn, null, cmdType, cmdText, cmdParms);
SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
cmd.Parameters.Clear();
return rdr;
}
catch
{
conn.Close();
throw;
}
}
///
/// Execute a SqlCommand that returns the first column of the first record against the database specified in the connection string
/// using the provided parameters.
///
///
/// e.g.:
/// Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
///
/// a valid connection string for a SqlConnection
/// the CommandType (stored procedure, text, etc.)
/// the stored procedure name or T-SQL command
/// an array of SqlParamters used to execute the command
/// An object that should be converted to the expected type using Convert.To{Type}
public static object ExecuteScalar(string connString, CommandType cmdType, string cmdText, params SqlParameter[] cmdParms)
{
SqlCommand cmd = new SqlCommand();
using (SqlConnection conn = new SqlConnection(connString))
{
PrepareCommand(cmd, conn, null, cmdType, cmdText, cmdParms);
object val = cmd.ExecuteScalar();
cmd.Parameters.Clear();
return val;
}
}
///
/// Execute a SqlCommand that returns the first column of the first record against an existing database connection
/// using the provided parameters.
///
///
/// e.g.:
/// Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
///
/// an existing database connection
/// the CommandType (stored procedure, text, etc.)
/// the stored procedure name or T-SQL command
/// an array of SqlParamters used to execute the command
/// An object that should be converted to the expected type using Convert.To{Type}
public static object ExecuteScalar(SqlConnection conn, CommandType cmdType, string cmdText, params SqlParameter[] cmdParms)
{
SqlCommand cmd = new SqlCommand();
PrepareCommand(cmd, conn, null, cmdType, cmdText, cmdParms);
object val = cmd.ExecuteScalar();
cmd.Parameters.Clear();
return val;
}
///
/// add parameter array to the cache
///
/// Key to the parameter cache
/// an array of SqlParamters to be cached
public static void CacheParameters(string cacheKey, params SqlParameter[] cmdParms)
{
DBHelper.paramCache[cacheKey] = cmdParms;
}
///
/// Retrieve cached parameters
///
/// key used to lookup parameters
/// Cached SqlParamters array
public static SqlParameter[] GetCachedParameters(string cacheKey)
{
SqlParameter[] cachedParms = (SqlParameter[])DBHelper.paramCache[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;
}
///
/// Prepare a command for execution
///
/// SqlCommand object
/// SqlConnection object
/// SqlTransaction object
/// Cmd type e.g. stored procedure or text
/// Command text, e.g. Select * from Products
/// SqlParameters to use in the command
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);
}
}
}
}