C# Access帮助类
更新时间：2020-05-01 21:55
public abstract class DbHelperOleDb
{
//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 static string connectionString = PubConstant.ConnectionString;
#region 公用方法
public static int GetMaxID(string FieldName, string TableName)
{
string strsql = "select max(" + FieldName + ")+1 from " + TableName;
object obj = DbHelperSQL.GetSingle(strsql);
if (obj == null)
{
return 1;
}
else
{
return int.Parse(obj.ToString());
}
}
public static bool Exists(string strSql)
{
object obj = DbHelperSQL.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 static bool Exists(string strSql, params OleDbParameter[] 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 (OleDbConnection connection = new OleDbConnection(connectionString))
{
using (OleDbCommand cmd = new OleDbCommand(SQLString, connection))
{
try
{
connection.Open();
int rows = cmd.ExecuteNonQuery();
return rows;
}
catch (System.Data.OleDb.OleDbException E)
{
connection.Close();
throw new Exception(E.Message);
}
}
}
}
/// <summary>
/// 执行多条SQL语句，实现数据库事务。
/// </summary>
/// <param name="SQLStringList">多条SQL语句</param>
public static void ExecuteSqlTran(ArrayList SQLStringList)
{
using (OleDbConnection conn = new OleDbConnection(connectionString))
{
conn.Open();
OleDbCommand cmd = new OleDbCommand();
cmd.Connection = conn;
OleDbTransaction tx = conn.BeginTransaction();
cmd.Transaction = tx;
try
{
for (int n = 0; n < SQLStringList.Count; n++)
{
string strsql = SQLStringList[n].ToString();
if (strsql.Trim().Length > 1)
{
cmd.CommandText = strsql;
cmd.ExecuteNonQuery();
}
}
tx.Commit();
}
catch (System.Data.OleDb.OleDbException E)
{
tx.Rollback();
throw new Exception(E.Message);
}
}
}
/// <summary>
/// 执行带一个存储过程参数的的SQL语句。
/// </summary>
/// <param name="SQLString">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 static int ExecuteSql(string SQLString, string content)
{
using (OleDbConnection connection = new OleDbConnection(connectionString))
{
OleDbCommand cmd = new OleDbCommand(SQLString, connection);
System.Data.OleDb.OleDbParameter myParameter = new System.Data.OleDb.OleDbParameter("@content", OleDbType.VarChar);
myParameter.Value = content;
cmd.Parameters.Add(myParameter);
try
{
connection.Open();
int rows = cmd.ExecuteNonQuery();
return rows;
}
catch (System.Data.OleDb.OleDbException E)
{
throw new Exception(E.Message);
}
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="strSQL">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 static int ExecuteSqlInsertImg(string strSQL, byte[] fs)
{
using (OleDbConnection connection = new OleDbConnection(connectionString))
{
OleDbCommand cmd = new OleDbCommand(strSQL, connection);
System.Data.OleDb.OleDbParameter myParameter = new System.Data.OleDb.OleDbParameter("@fs", OleDbType.Binary);
myParameter.Value = fs;
cmd.Parameters.Add(myParameter);
try
{
connection.Open();
int rows = cmd.ExecuteNonQuery();
return rows;
}
catch (System.Data.OleDb.OleDbException E)
{
throw new Exception(E.Message);
}
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="SQLString">计算查询结果语句</param>
/// <returns>查询结果（object）</returns>
public static object GetSingle(string SQLString)
{
using (OleDbConnection connection = new OleDbConnection(connectionString))
{
using (OleDbCommand cmd = new OleDbCommand(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.OleDb.OleDbException e)
{
connection.Close();
throw new Exception(e.Message);
}
}
}
}
/// <summary>
/// 执行查询语句，返回OleDbDataReader
/// </summary>
/// <param name="strSQL">查询语句</param>
/// <returns>OleDbDataReader</returns>
public static OleDbDataReader ExecuteReader(string strSQL)
{
OleDbConnection connection = new OleDbConnection(connectionString);
OleDbCommand cmd = new OleDbCommand(strSQL, connection);
try
{
connection.Open();
OleDbDataReader myReader = cmd.ExecuteReader();
return myReader;
}
catch (System.Data.OleDb.OleDbException 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 (OleDbConnection connection = new OleDbConnection(connectionString))
{
DataSet ds = new DataSet();
try
{
connection.Open();
OleDbDataAdapter command = new OleDbDataAdapter(SQLString, connection);
command.Fill(ds, "ds");
}
catch (System.Data.OleDb.OleDbException ex)
{
throw new Exception(ex.Message);
}
return ds;
}
}
#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="SQLString">SQL语句</param>
/// <returns>影响的记录数</returns>
public static int ExecuteSql(string SQLString, params OleDbParameter[] cmdParms)
{
using (OleDbConnection connection = new OleDbConnection(connectionString))
{
using (OleDbCommand cmd = new OleDbCommand())
{
try
{
PrepareCommand(cmd, connection, null, SQLString, cmdParms);
int rows = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return rows;
}
catch (System.Data.OleDb.OleDbException E)
{
throw new Exception(E.Message);
}
}
}
}
/// <summary>
/// 执行多条SQL语句，实现数据库事务。
/// </summary>
/// <param name="SQLStringList">SQL语句的哈希表（key为sql语句，value是该语句的OleDbParameter[]）</param>
public static void ExecuteSqlTran(Hashtable SQLStringList)
{
using (OleDbConnection conn = new OleDbConnection(connectionString))
{
conn.Open();
using (OleDbTransaction trans = conn.BeginTransaction())
{
OleDbCommand cmd = new OleDbCommand();
try
{
//循环
foreach (DictionaryEntry myDE in SQLStringList)
{
string cmdText = myDE.Key.ToString();
OleDbParameter[] cmdParms = (OleDbParameter[])myDE.Value;
PrepareCommand(cmd, conn, trans, cmdText, cmdParms);
int val = cmd.ExecuteNonQuery();
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="SQLString">计算查询结果语句</param>
/// <returns>查询结果（object）</returns>
public static object GetSingle(string SQLString, params OleDbParameter[] cmdParms)
{
using (OleDbConnection connection = new OleDbConnection(connectionString))
{
using (OleDbCommand cmd = new OleDbCommand())
{
try
{
PrepareCommand(cmd, connection, null, SQLString, 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.OleDb.OleDbException e)
{
throw new Exception(e.Message);
}
}
}
}
/// <summary>
/// 执行查询语句，返回OleDbDataReader
/// </summary>
/// <param name="strSQL">查询语句</param>
/// <returns>OleDbDataReader</returns>
public static OleDbDataReader ExecuteReader(string SQLString, params OleDbParameter[] cmdParms)
{
OleDbConnection connection = new OleDbConnection(connectionString);
OleDbCommand cmd = new OleDbCommand();
try
{
PrepareCommand(cmd, connection, null, SQLString, cmdParms);
OleDbDataReader myReader = cmd.ExecuteReader();
cmd.Parameters.Clear();
return myReader;
}
catch (System.Data.OleDb.OleDbException 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, params OleDbParameter[] cmdParms)
{
using (OleDbConnection connection = new OleDbConnection(connectionString))
{
OleDbCommand cmd = new OleDbCommand();
PrepareCommand(cmd, connection, null, SQLString, cmdParms);
using (OleDbDataAdapter da = new OleDbDataAdapter(cmd))
{
DataSet ds = new DataSet();
try
{
da.Fill(ds, "ds");
cmd.Parameters.Clear();
}
catch (System.Data.OleDb.OleDbException ex)
{
throw new Exception(ex.Message);
}
return ds;
}
}
}
private static void PrepareCommand(OleDbCommand cmd, OleDbConnection conn, OleDbTransaction trans, string cmdText, OleDbParameter[] 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 (OleDbParameter parm in cmdParms)
cmd.Parameters.Add(parm);
}
}
#endregion
}