C# 程序员参考--OLE DB 教程

　　 

OLE DB 是用于访问数据的基于 COM 的应用程序编程接口 (API)。OLE DB 支持访问以 OLE DB 提供程序可以使用的任何格式（数据库、电子表格、文本文件等）存储的数据。

每个 OLE DB 提供程序从某一特定类型的数据源（例如 SQL Server 数据库、Microsoft Aclearcase/" target="_blank" >ccess 数据库或 Microsoft Excel 电子表格）公开数据。

本教程说明如何从 C# 应用程序中使用 Microsoft Access 数据库。

教程
本教程说明如何从 C# 中使用 Microsoft Access 数据库。它显示如何创建数据集并从数据库向该数据集添加表。本示例程序中使用的 BugTypes.mdb 数据库是 Microsoft Access 2000 .MDB 文件。

示例
本程序访问 BugTypes.mdb 数据库，创建一个数据集并向其中添加表，然后显示表、列和行的数目。它还显示每行的标题。

// OleDbSample.cs
using System;
using System.Data;
using System.Data.OleDb;
using System.Xml.Serialization;

public class MainClass {
    public static void Main ()
    {
            // Set Access connection and select strings.
            // The path to BugTypes.MDB must be changed if you build
            // the sample from the command line:
#if USINGPROJECTSYSTEM
            string strAccessConn = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=..\\..\\BugTypes.MDB";
#else
            string strAccessConn = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=BugTypes.MDB";
#endif
            string strAccessSelect = "SELECT * FROM Categories";
 
            // Create the dataset and add the Categories table to it:
            DataSet myDataSet = new DataSet();
            OleDbConnection myAccessConn = null;
            try
            {
                  myAccessConn = new OleDbConnection(strAccessConn);
            }
            catch(Exception ex)
            {
                  Console.WriteLine("Error: Failed to create a database connection. \n{0}", ex.Message);
                  return;
            }
 
            try
            {
           
                  OleDbCommand myAccessCommand = new OleDbCommand(strAccessSelect,myAccessConn);
                  OleDbDataAdapter myDataAdapter = new OleDbDataAdapter(myAccessCommand);
 
                  myAccessConn.Open();
                  myDataAdapter.Fill(myDataSet,"Categories");
 
            }
            catch (Exception ex)
            {
                  Console.WriteLine("Error: Failed to retrieve the required data from the DataBase.\n{0}", ex.Message);
                  return;
            }
            finally
            {
                  myAccessConn.Close();
            }
 
            // A dataset can contain multiple tables, so let's get them
            // all into an array:
            DataTableCollection dta = myDataSet.Tables;
            foreach (DataTable dt in dta)
            {
            Console.WriteLine("Found data table {0}", dt.TableName);
            }
         
            // The next two lines show two different ways you can get the
            // count of tables in a dataset:
            Console.WriteLine("{0} tables in data set", myDataSet.Tables.Count);
            Console.WriteLine("{0} tables in data set", dta.Count);
            // The next several lines show how to get information on
            // a specific table by name from the dataset:
            Console.WriteLine("{0} rows in Categories table", myDataSet.Tables["Categories"].Rows.Count);
            // The column info is automatically fetched from the database,
            // so we can read it here:
            Console.WriteLine("{0} columns in Categories table", myDataSet.Tables["Categories"].Columns.Count);
            DataColumnCollection drc = myDataSet.Tables["Categories"].Columns;
            int i = 0;
            foreach (DataColumn dc in drc)
            {
                  // Print the column subscript, then the column's name
                  // and its data type:
                  Console.WriteLine("Column name[{0}] is {1}, of type {2}",i++ , dc.ColumnName, dc.DataType);
            }
            DataRowCollection dra = myDataSet.Tables["Categories"].Rows;
            foreach (DataRow dr in dra)
            {
                  // Print the CategoryID as a subscript, then the CategoryName:
                  Console.WriteLine("CategoryName[{0}] is {1}", dr[0], dr[1]);
            }
     
   }
}
输出
BugTypes.mdb 数据库的 Categories 表包含下列信息：

类别 ID 类别名称
1 Bugbash Stuff
2 Appweek Bugs
3 .NET Framework Reports
4 Internal Support

当运行此示例时，屏幕上将显示下列输出：

Found data table Categories
1 tables in data set
1 tables in data set
4 rows in Categories table
2 columns in Categories table
Column name[0] is CategoryID, of type System.Int32
Column name[1] is CategoryName, of type System.String
CategoryName[1] is Bugbash Stuff
CategoryName[2] is Appweek Bugs
CategoryName[3] is .NET Framework Reports
CategoryName[4] is Internal Support

原文转自：http://www.ltesting.net