SQLHelper

Posted 2020-12-03 jeffrey77

using System;
using System.Collections;
using System.Collections.Specialized;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using System.Data.Common;
using System.Collections.Generic;

namespace DBUtility
{
public class SQLHelper
{
//数据库连接字符串(web.config来配置)，可以动态更改connectionString支持多数据库.
public string connectionString = ConfigurationManager.ConnectionStrings["connStr"].ConnectionString;
public SQLHelper()
{
}
public SQLHelper(string connStr)
{
connectionString = connStr;
}

#region 公用方法
/// <summary>
/// 判断是否存在某表的某个字段
/// </summary>
/// <param name="tableName">表名称</param>
/// <param name="columnName">列名称</param>
/// <returns>是否存在</returns>
public bool ColumnExists(string tableName, string columnName)
{
string sql = "select count(1) from syscolumns where [id]=object_id(‘" + tableName + "‘) and [name]=‘" + columnName + "‘";
object res = GetSingle(sql);
if (res == null)
{
return false;
}
return Convert.ToInt32(res) > 0;
}

/// <summary>
/// 取得某个字段下一个最大编号
/// </summary>
/// <param name="fieldName"></param>
/// <param name="tableName"></param>
/// <returns></returns>
public 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 bool Exists(string strSql)
{
object obj = GetSingle(strSql);
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;
}
}

/// <summary>
/// 表是否存在
/// </summary>
/// <param name="tableName"></param>
/// <returns></returns>
public bool TabExists(string tableName)
{
string strsql = "select count(*) from sysobjects where id = object_id(N‘[" + tableName + "]‘) and OBJECTPROPERTY(id, N‘IsUserTable‘) = 1";
//string strsql = "SELECT count(*) FROM sys.objects WHERE object_id = OBJECT_ID(N‘[dbo].[" + TableName + "]‘) AND type in (N‘U‘)";
object obj = GetSingle(strsql);
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;
}
}

public 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="sql">SQL语句</param>
/// <returns>影响的记录数</returns>
public int ExecuteSql(string sql)
{
using (SqlConnection connection = new SqlConnection(connectionString))
{
using (SqlCommand cmd = new SqlCommand(sql, connection))
{
try
{
connection.Open();
int count = cmd.ExecuteNonQuery();
return count;
}
catch (SqlException e)
{
connection.Close();
throw e;
}
}
}
}

/// <summary>
/// 执行多条SQL语句，实现数据库事务。
/// </summary>
/// <param name="sqlList">多条SQL语句</param>
public int ExecuteSqlTran(List<String> sqlList)
{
using (SqlConnection conn = new SqlConnection(connectionString))
{
conn.Open();
SqlCommand cmd = new SqlCommand();
cmd.Connection = conn;
SqlTransaction ts = conn.BeginTransaction();
cmd.Transaction = ts;
try
{
int count = 0;
for (int n = 0; n < sqlList.Count; n++)
{
string strsql = sqlList[n];
if (strsql.Trim().Length > 1)
{
cmd.CommandText = strsql;
count += cmd.ExecuteNonQuery();
}
}
ts.Commit();
return count;
}
catch
{
ts.Rollback();
return 0;
}
}
}
/// <summary>
/// 执行带一个存储过程参数的的SQL语句。
/// </summary>
/// <param name="sql">SQL语句</param>
/// <param name="content">参数内容,比如一个字段是格式复杂的文章，有特殊符号，可以通过这个方式添加</param>
/// <returns>影响的记录数</returns>
public int ExecuteSql(string sql, string content)
{
using (SqlConnection connection = new SqlConnection(connectionString))
{
SqlCommand cmd = new SqlCommand(sql, connection);
System.Data.SqlClient.SqlParameter myParameter = new System.Data.SqlClient.SqlParameter("@content", SqlDbType.NText);
myParameter.Value = content;
cmd.Parameters.Add(myParameter);
try
{
connection.Open();
int rows = cmd.ExecuteNonQuery();
return rows;
}
catch (System.Data.SqlClient.SqlException e)
{
throw e;
}
finally
{
cmd.Dispose();
connection.Close();
}
}
}
/// <summary>
/// 执行带一个存储过程参数的的SQL语句。
/// </summary>
/// <param name="sql">SQL语句</param>
/// <param name="content">参数内容,比如一个字段是格式复杂的文章，有特殊符号，可以通过这个方式添加</param>
/// <returns>影响的记录数</returns>
public object ExecuteSqlGet(string sql, string content)
{
using (SqlConnection connection = new SqlConnection(connectionString))
{
SqlCommand cmd = new SqlCommand(sql, connection);
System.Data.SqlClient.SqlParameter myParameter = new System.Data.SqlClient.SqlParameter("@content", SqlDbType.NText);
myParameter.Value = content;
cmd.Parameters.Add(myParameter);
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)
{
throw e;
}
finally
{
cmd.Dispose();
connection.Close();
}
}
}
/// <summary>
/// 向数据库里插入图像格式的字段(和上面情况类似的另一种实例)
/// </summary>
/// <param name="sql">SQL语句</param>
/// <param name="fs">图像字节,数据库的字段类型为image的情况</param>
/// <returns>影响的记录数</returns>
public int ExecuteSqlInsertImg(string sql, byte[] fs)
{
using (SqlConnection connection = new SqlConnection(connectionString))
{
SqlCommand cmd = new SqlCommand(sql, connection);
System.Data.SqlClient.SqlParameter myParameter = new System.Data.SqlClient.SqlParameter("@fs", SqlDbType.Image);
myParameter.Value = fs;
cmd.Parameters.Add(myParameter);
try
{
connection.Open();
int count = cmd.ExecuteNonQuery();
return count;
}
catch (System.Data.SqlClient.SqlException e)
{
throw e;
}
finally
{
cmd.Dispose();
connection.Close();
}
}
}

/// <summary>
/// 执行一条计算查询结果语句，返回查询结果（object）。
/// </summary>
/// <param name="sql">计算查询结果语句</param>
/// <returns>查询结果（object）</returns>
public object GetSingle(string sql)
{
using (SqlConnection connection = new SqlConnection(connectionString))
{
using (SqlCommand cmd = new SqlCommand(sql, 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 e;
}
}
}
}

/// <summary>
/// 执行查询语句，返回SqlDataReader ( 注意：调用该方法后，一定要对SqlDataReader进行Close )
/// </summary>
/// <param name="sql">查询语句</param>
/// <returns>SqlDataReader</returns>
public SqlDataReader ExecuteReader(string sql)
{
SqlConnection connection = new SqlConnection(connectionString);
SqlCommand cmd = new SqlCommand(sql, connection);
try
{
connection.Open();
SqlDataReader myReader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
return myReader;
}
catch (System.Data.SqlClient.SqlException e)
{
throw e;
}

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

/// <summary>
/// 执行查询语句，返回DataTable
/// </summary>
/// <param name="sql"></param>
/// <returns></returns>
public DataTable QueryData(string sql)
{
using (SqlConnection connection = new SqlConnection(connectionString))
{
DataTable table = new DataTable();
connection.Open();
SqlDataAdapter command = new SqlDataAdapter(sql, connection);
command.Fill(table);
return table;
}
}

#endregion

#region 执行带参数的SQL语句

/// <summary>
/// 执行SQL语句，返回影响的记录数
/// </summary>
/// <param name="sql">SQL语句</param>
/// <returns>影响的记录数</returns>
public int ExecuteSql(string sql, params SqlParameter[] cmdParms)
{
using (SqlConnection connection = new SqlConnection(connectionString))
{
using (SqlCommand cmd = new SqlCommand())
{
try
{
PrepareCommand(cmd, connection, null, sql, cmdParms);
int count = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return count;
}
catch (System.Data.SqlClient.SqlException e)
{
throw e;
}
}
}
}

/// <summary>
/// 执行多条SQL语句，实现数据库事务。
/// </summary>
/// <param name="sqlList">SQL语句的哈希表（key为sql语句，value是该语句的SqlParameter[]）</param>
public void ExecuteSqlTran(Hashtable sqlList)
{
using (SqlConnection conn = new SqlConnection(connectionString))
{
conn.Open();
using (SqlTransaction trans = conn.BeginTransaction())
{
SqlCommand cmd = new SqlCommand();
try
{
//循环
foreach (DictionaryEntry myDE in sqlList)
{
string cmdText = myDE.Key.ToString();
SqlParameter[] cmdParms = (SqlParameter[])myDE.Value;
PrepareCommand(cmd, conn, trans, cmdText, cmdParms);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
}
trans.Commit();
}
catch
{
trans.Rollback();
throw;
}
}
}
}

/// <summary>
/// 执行多条SQL语句，实现数据库事务。
/// </summary>
/// <param name="sqlList">SQL语句的哈希表（key为sql语句，value是该语句的SqlParameter[]）</param>
public void ExecuteSqlTranWithIndentity(Hashtable sqlList)
{
using (SqlConnection conn = new SqlConnection(connectionString))
{
conn.Open();
using (SqlTransaction trans = conn.BeginTransaction())
{
SqlCommand cmd = new SqlCommand();
try
{
int indentity = 0;
//循环
foreach (DictionaryEntry myDE in sqlList)
{
string cmdText = myDE.Key.ToString();
SqlParameter[] cmdParms = (SqlParameter[])myDE.Value;
foreach (SqlParameter q in cmdParms)
{
if (q.Direction == ParameterDirection.InputOutput)
{
q.Value = indentity;
}
}
PrepareCommand(cmd, conn, trans, cmdText, cmdParms);
int val = cmd.ExecuteNonQuery();
foreach (SqlParameter q in cmdParms)
{
if (q.Direction == ParameterDirection.Output)
{
indentity = Convert.ToInt32(q.Value);
}
}
cmd.Parameters.Clear();
}
trans.Commit();
}
catch
{
trans.Rollback();
throw;
}
}
}
}
/// <summary>
/// 执行一条计算查询结果语句，返回查询结果（object）。
/// </summary>
/// <param name="sql">计算查询结果语句</param>
/// <returns>查询结果（object）</returns>
public object GetSingle(string sql, params SqlParameter[] cmdParms)
{
using (SqlConnection connection = new SqlConnection(connectionString))
{
using (SqlCommand cmd = new SqlCommand())
{
try
{
PrepareCommand(cmd, connection, null, sql, cmdParms);
object obj = cmd.ExecuteScalar();
cmd.Parameters.Clear();
if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
{
return null;
}
else
{
return obj;
}
}
catch (System.Data.SqlClient.SqlException e)
{
throw e;
}
}
}
}

/// <summary>
/// 执行查询语句，返回SqlDataReader ( 注意：调用该方法后，一定要对SqlDataReader进行Close )
/// </summary>
/// <param name="strSQL">查询语句</param>
/// <returns>SqlDataReader</returns>
public SqlDataReader ExecuteReader(string sql, params SqlParameter[] cmdParms)
{
SqlConnection connection = new SqlConnection(connectionString);
SqlCommand cmd = new SqlCommand();
try
{
PrepareCommand(cmd, connection, null, sql, cmdParms);
SqlDataReader myReader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
cmd.Parameters.Clear();
return myReader;
}
catch (System.Data.SqlClient.SqlException e)
{
throw e;
}
// finally
// {
// cmd.Dispose();
// connection.Close();
// }

}

/// <summary>
/// 执行查询语句，返回DataSet
/// </summary>
/// <param name="sql">查询语句</param>
/// <returns>DataSet</returns>
public DataSet Query(string sql, params SqlParameter[] cmdParms)
{
using (SqlConnection connection = new SqlConnection(connectionString))
{
SqlCommand cmd = new SqlCommand();
PrepareCommand(cmd, connection, null, sql, cmdParms);
using (SqlDataAdapter da = new SqlDataAdapter(cmd))
{
DataSet ds = new DataSet();
try
{
da.Fill(ds, "ds");
cmd.Parameters.Clear();
}
catch (System.Data.SqlClient.SqlException ex)
{
throw new Exception(ex.Message);
}
return ds;
}
}
}

/// <summary>
/// 执行查询语句，返回DataTable
/// </summary>
/// <param name="sql"></param>
/// <param name="cmdParms"></param>
/// <returns></returns>
public DataTable QueryData(string sql, params SqlParameter[] cmdParms)
{
using (SqlConnection connection = new SqlConnection(connectionString))
{
SqlCommand cmd = new SqlCommand();
PrepareCommand(cmd, connection, null, sql, cmdParms);
using (SqlDataAdapter da = new SqlDataAdapter(cmd))
{
DataTable table = new DataTable();
da.Fill(table);
cmd.Parameters.Clear();
return table;
}
}
}

private static void PrepareCommand(SqlCommand cmd, SqlConnection conn, SqlTransaction trans, 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 = CommandType.Text;//cmdType;
if (cmdParms != null)
{
foreach (SqlParameter parameter in cmdParms)
{
if ((parameter.Direction == ParameterDirection.InputOutput || parameter.Direction == ParameterDirection.Input) && parameter.Value == null)
{
parameter.Value = DBNull.Value;
}
cmd.Parameters.Add(parameter);
}
}
}

#endregion

#region 存储过程操作

/// <summary>
/// 执行存储过程，返回SqlDataReader ( 注意：调用该方法后，一定要对SqlDataReader进行Close )
/// </summary>
/// <param name="storedProcName">存储过程名</param>
/// <param name="parameters">存储过程参数</param>
/// <returns>SqlDataReader</returns>
public SqlDataReader RunProcedure(string storedProcName, IDataParameter[] parameters)
{
using (SqlConnection connection = new SqlConnection(connectionString))
{
SqlDataReader returnReader;
connection.Open();
SqlCommand command = BuildQueryCommand(connection, storedProcName, parameters);
command.CommandType = CommandType.StoredProcedure;
returnReader = command.ExecuteReader(CommandBehavior.CloseConnection);
return returnReader;
}
}

/// <summary>
/// 执行存储过程
/// </summary>
/// <param name="storedProcName">存储过程名</param>
/// <param name="parameters">存储过程参数</param>
/// <param name="tableName">DataSet结果中的表名</param>
/// <returns>DataSet</returns>
public DataSet RunProcedure(string storedProcName, IDataParameter[] parameters, string tableName)
{
using (SqlConnection connection = new SqlConnection(connectionString))
{
DataSet dataSet = new DataSet();
connection.Open();
SqlDataAdapter sqlDA = new SqlDataAdapter();
sqlDA.SelectCommand = BuildQueryCommand(connection, storedProcName, parameters);
sqlDA.Fill(dataSet, tableName);
connection.Close();
return dataSet;
}
}

/// <summary>
/// 构建 SqlCommand 对象(用来返回一个结果集，而不是一个整数值)
/// </summary>
/// <param name="connection">数据库连接</param>
/// <param name="storedProcName">存储过程名</param>
/// <param name="parameters">存储过程参数</param>
/// <returns>SqlCommand</returns>
private static SqlCommand BuildQueryCommand(SqlConnection connection, string storedProcName, IDataParameter[] parameters)
{
SqlCommand command = new SqlCommand(storedProcName, connection);
command.CommandType = CommandType.StoredProcedure;
foreach (SqlParameter parameter in parameters)
{
if (parameter != null)
{
// 检查未分配值的输出参数,将其分配以DBNull.Value.
if ((parameter.Direction == ParameterDirection.InputOutput || parameter.Direction == ParameterDirection.Input) &&
(parameter.Value == null))
{
parameter.Value = DBNull.Value;
}
command.Parameters.Add(parameter);
}
}

return command;
}

/// <summary>
/// 执行存储过程，返回影响的行数
/// </summary>
/// <param name="storedProcName">存储过程名</param>
/// <param name="parameters">存储过程参数</param>
/// <param name="rowsAffected">影响的行数</param>
/// <returns></returns>
public int RunProcedure(string storedProcName, IDataParameter[] parameters, out int rowsAffected)
{
using (SqlConnection connection = new SqlConnection(connectionString))
{
int result;
connection.Open();
SqlCommand command = BuildIntCommand(connection, storedProcName, parameters);
rowsAffected = command.ExecuteNonQuery();
result = (int)command.Parameters["ReturnValue"].Value;
//Connection.Close();
return result;
}
}

/// <summary>
/// 创建 SqlCommand 对象实例(用来返回一个整数值)
/// </summary>
/// <param name="storedProcName">存储过程名</param>
/// <param name="parameters">存储过程参数</param>
/// <returns>SqlCommand 对象实例</returns>
private static SqlCommand BuildIntCommand(SqlConnection connection, string storedProcName, IDataParameter[] parameters)
{
SqlCommand command = BuildQueryCommand(connection, storedProcName, parameters);
command.Parameters.Add(new SqlParameter("ReturnValue",
SqlDbType.Int, 4, ParameterDirection.ReturnValue,
false, 0, 0, string.Empty, DataRowVersion.Default, null));
return command;
}
#endregion

}
}