using System;
using System.Data;
using System.Data.OleDb;

namespace GeologyToolkit
{
    internal class MdbHelper
    {
        /// <summary>
        ///     构建函数
        /// </summary>
        /// <param name="fileName">MDB文件（含完整路徑）</param>
        public MdbHelper(string fileName)
        {
            this.fileName = fileName;
            connectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + fileName;
        }

        private readonly string connectionString;
        private readonly string fileName;
        private OleDbConnection odcConnection;

        /// <summary>
        ///     断开连接（关闭据库文件）
        /// </summary>
        public void Close()
        {
            odcConnection.Close();
        }

        /// <summary>
        ///     根据sql命令返回一个DataSet
        /// </summary>
        /// <param name="sql">sql命令</param>
        /// <returns>以DataTable形式返回数据</returns>
        public DataSet GetDataSet(string sql)
        {
            DataSet ds = new DataSet();

            try
            {
                OleDbDataAdapter adapter = new OleDbDataAdapter(sql, odcConnection);
                adapter.Fill(ds);
            }
            catch (Exception)
            {
                throw new Exception("sql语句： " + sql + " 执行失败！");
            }

            return ds;
        }

        /// <summary>
        ///     建立连接（打开数据库文件）
        /// </summary>
        public void Open()
        {
            // 建立连接
            odcConnection = new OleDbConnection(connectionString);
            // 打开连接
            odcConnection.Open();
        }
    }
}