1、数据连接ADO应用程序实例面是一个简单的 ADO.NET 应用程序，它从数据源中返回结果并输出到控制台或命令提示符窗口。 本主题中的示例显示如何使用 SQL Server .NET Framework 数据提供程序 (System.Data.SqlClient)、OLE DB .NET Framework 数据提供程序 (System.Data.OleDb)、ODBC .NET Framework 数据提供程序 (System.Data.Odbc) 和 Oracle .NET Framework 数据提供程序 (System.Data.OracleClient) 连接并检索数据。如果需要，所有
2、数据提供程序都可以在单个的应用程序中使用。下面的 SqlClient 示例假定您可以连接到 Microsoft SQL Server 7.0 或更高版本上的 Northwind 示例数据库，并使用 SqlDataReader 从 Categories 表返回记录列表。OleDb 和 Odbc 示例假定已与 Microsoft Access Northwind 示例数据库建立连接。OracleClient 示例假定已与 Oracle 服务器上的 DEMO.CUSTOMER 建立连接。还必须添加对 System.Data.OracleClient.dll 的引用。SqlClientC#using
3、System;using System.Data;using System.Data.SqlClient;class Program static void Main() string connectionString = GetConnectionString(); string queryString = SELECT CategoryID, CategoryName FROM dbo.Categories; using (SqlConnection connection = new SqlConnection(connectionString) SqlCommand command =
4、connection.CreateCommand(); command.CommandText = queryString; try connection.Open(); SqlDataReader reader = command.ExecuteReader(); while (reader.Read() Console.WriteLine(t0t1, reader0, reader1); reader.Close(); catch (Exception ex) Console.WriteLine(ex.Message); static private string GetConnectio
5、nString() / To avoid storing the connection string in your code, / you can retrieve it from a configuration file. return Data Source=(local);Initial Catalog=Northwind; + Integrated Security=SSPI; VBOption Explicit OnOption Strict OnImports SystemImports System.DataImports System.Data.SqlClientPublic
6、 Class Program Public Shared Sub Main() Dim connectionString As String = GetConnectionString() Dim queryString As String = _ SELECT CategoryID, CategoryName FROM dbo.Categories; Using connection As New SqlConnection(connectionString) Dim command As SqlCommand = connection.CreateCommand() command.Com
7、mandText = queryString Try connection.Open() Dim dataReader As SqlDataReader = _ command.ExecuteReader() Do While dataReader.Read() Console.WriteLine(vbTab & 0 & vbTab & 1, _ dataReader(0), dataReader(1) Loop dataReader.Close() Catch ex As Exception Console.WriteLine(ex.Message) End Try End Using En
8、d Sub Private Shared Function GetConnectionString() As String To avoid storing the connection string in your code, you can retrieve it from a configuration file. Return Data Source=(local);Initial Catalog=Northwind; _ & Integrated Security=SSPI; End FunctionEnd ClassOleDbVB：Option Explicit OnOption
9、Strict OnImports SystemImports System.DataImports System.Data.OleDbPublic Class Program Public Shared Sub Main() Dim connectionString As String = GetConnectionString() Dim queryString As String = _ SELECT CategoryID, CategoryName FROM Categories; Using connection As New OleDbConnection(connectionStr
10、ing) Dim command As OleDbCommand = connection.CreateCommand() command.CommandText = queryString Try connection.Open() Dim dataReader As OleDbDataReader = _ command.ExecuteReader() Do While dataReader.Read() Console.WriteLine(vbTab & 0 & vbTab & 1, _ dataReader(0), dataReader(1) Loop dataReader.Close
11、() Catch ex As Exception Console.WriteLine(ex.Message) End Try End Using End Sub Private Shared Function GetConnectionString() As String To avoid storing the connection string in your code, you can retrieve it from a configuration file. Assumes Northwind.mdb is located in c:Data folder. Return Provi
12、der=Microsoft.Jet.OLEDB.4.0;Data Source= _ & c:DataNorthwind.mdb;User Id=admin;Password=; End FunctionEnd ClassC#using System;using System.Data;using System.Data.OleDb;class Program static void Main() string connectionString = GetConnectionString(); string queryString = SELECT CategoryID, CategoryNa
13、me FROM Categories; using (OleDbConnection connection = new OleDbConnection(connectionString) OleDbCommand command = connection.CreateCommand(); command.CommandText = queryString; try connection.Open(); OleDbDataReader reader = command.ExecuteReader(); while (reader.Read() Console.WriteLine(t0t1, re
14、ader0, reader1); reader.Close(); catch (Exception ex) Console.WriteLine(ex.Message); static private string GetConnectionString() / To avoid storing the connection string in your code, / you can retrieve it from a configuration file. / Assumes Northwind.mdb is located in the c:Data folder. return Pro
15、vider=Microsoft.Jet.OLEDB.4.0;Data Source= + c:DataNorthwind.mdb;User Id=admin;Password=; OdbcVB：Option Explicit OnOption Strict OnImports SystemImports System.DataImports System.Data.OdbcPublic Class Program Public Shared Sub Main() Dim connectionString As String = GetConnectionString() Dim querySt
16、ring As String = _ SELECT CategoryID, CategoryName FROM Categories; Using connection As New OdbcConnection(connectionString) Dim command As OdbcCommand = connection.CreateCommand() command.CommandText = queryString Try connection.Open() Dim dataReader As OdbcDataReader = _ command.ExecuteReader() Do
17、 While dataReader.Read() Console.WriteLine(vbTab & 0 & vbTab & 1, _ dataReader(0), dataReader(1) Loop dataReader.Close() Catch ex As Exception Console.WriteLine(ex.Message) End Try End Using End Sub Private Shared Function GetConnectionString() As String To avoid storing the connection string in you
18、r code, you can retrieve it from a configuration file. Assumes Northwind.mdb is located in c:Data folder. Return Driver=Microsoft Access Driver (*.mdb); _ & Dbq=c:DataNorthwind.mdb;Uid=Admin;Pwd=; End FunctionEnd ClassC#using System;using System.Data;using System.Data.Odbc;class Program static void
19、Main() string connectionString = GetConnectionString(); string queryString = SELECT CategoryID, CategoryName FROM Categories; using (OdbcConnection connection = new OdbcConnection(connectionString) OdbcCommand command = connection.CreateCommand(); command.CommandText = queryString; try connection.Op
20、en(); OdbcDataReader reader = command.ExecuteReader(); while (reader.Read() Console.WriteLine(t0t1, reader0, reader1); reader.Close(); catch (Exception ex) Console.WriteLine(ex.Message); static private string GetConnectionString() / To avoid storing the connection string in your code, / you can retr
21、ieve it from a configuration file. / Assumes Northwind.mdb is located in the c:Data folder. return Driver=Microsoft Access Driver (*.mdb); + Dbq=c:DataNorthwind.mdb;Uid=Admin;Pwd=; OracleClientVB：Option Explicit OnOption Strict OnImports SystemImports System.DataImports System.Data.OracleClientPubli
22、c Class Program Public Shared Sub Main() Dim connectionString As String = GetConnectionString() Dim queryString As String = _ SELECT CUSTOMER_ID, NAME FROM DEMO.CUSTOMER Using connection As New OracleConnection(connectionString) Dim command As OracleCommand = connection.CreateCommand() command.Comma
23、ndText = queryString Try connection.Open() Dim dataReader As OracleDataReader = _ command.ExecuteReader() Do While dataReader.Read() Console.WriteLine(vbTab & 0 & vbTab & 1, _ dataReader(0), dataReader(1) Loop dataReader.Close() Catch ex As Exception Console.WriteLine(ex.Message) End Try End Using E
24、nd Sub Private Shared Function GetConnectionString() As String To avoid storing the connection string in your code, you can retrieve it from a configuration file. Return Data Source=ThisOracleServer;Integrated Security=yes; End FunctionEnd ClassC#：using System;using System.Data;using System.Data.Ora
25、cleClient;class Program static void Main() string connectionString = GetConnectionString(); string queryString = SELECT CUSTOMER_ID, NAME FROM DEMO.CUSTOMER; using (OracleConnection connection = new OracleConnection(connectionString) OracleCommand command = connection.CreateCommand(); command.Comman
26、dText = queryString; try connection.Open(); OracleDataReader reader = command.ExecuteReader(); while (reader.Read() Console.WriteLine(t0t1, reader0, reader1); reader.Close(); catch (Exception ex) Console.WriteLine(ex.Message); static private string GetConnectionString() / To avoid storing the connection string in your code, / you can retrieve it from a configuration file. / Assumes Northwind.mdb is located in the c:Data folder. return Data Source=ThisOracleServer;Integrated Security=yes;
