C#连接数据库_catch (system.exception ex) { closeconnection(); r-优快云博客

本文介绍了一个用于访问Access数据库的C#类SqlHelper。该类提供了连接字符串配置、执行SQL语句、获取数据集及数据表的方法。通过示例展示了如何使用OleDb连接本地Access数据库文件并执行基本的数据检索操作。

class SqlHelper
{

public static string connectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + Environment.CurrentDirectory + "//hy_EProjectLand.accdb;Persist Security Info=False;";

        public SqlHelper()
        {

        }

        /// <summary>
        /// 获取数据集
        /// </summary>
        /// <param name="sqlStr"></param>
        /// <returns></returns>
        public static DataSet GetDataset(string sqlStr)
        {
            OleDbConnection connection = new OleDbConnection(connectionString);
            DataSet ds = new DataSet();
            try
            {
                connection.Open();
                OleDbDataAdapter da = new OleDbDataAdapter(sqlStr, connection);
                da.Fill(ds);
                return ds;
            }
            catch (System.Exception ex)
            {
                return null;
            }
            finally
            {
                connection.Close();
            }
        }

        /// <summary>
        /// 获取数据表
        /// </summary>
        /// <param name="sqlStr"></param>
        /// <returns></returns>
        public static DataTable GetDataTable(string sqlStr)
        {
            OleDbConnection connection = new OleDbConnection(connectionString);
            DataSet ds = new DataSet();
            try
            {
                connection.Open();
                OleDbDataAdapter da = new OleDbDataAdapter(sqlStr, connection);
                da.Fill(ds);
                if (ds.Tables.Count > 0)
                {
                    return ds.Tables[0];
                }
                else
                {
                    return null;
                }
            }
            catch (System.Exception ex)
            {
                return null;
            }
            finally
            {
                connection.Close();
            }
        }

        /// <summary>
        /// 执行SQL语句
        /// </summary>
        /// <param name="sqlStr"></param>
        /// <returns></returns>
        public static bool Query(string sqlStr)
        {
            OleDbConnection connection = new OleDbConnection(connectionString);
            OleDbCommand cmd = new OleDbCommand(sqlStr, connection);

            try
            {
                connection.Open();
                cmd.ExecuteNonQuery();
                return true;

            }
            catch (System.Exception ex)
            {

                return false;
            }
            finally
            {
                connection.Close();
            }

        }
    }