psqlODBC 使用指南 - C#

作者：Dave Page ([email protected])
发布日期：2002 年 4 月 12 日
描述：基于示例的迷你指南，介绍如何使用 C# 访问 PostgreSQL

本文档提供了一些示例代码，帮助您开始使用 C# 和 PostgreSQL。

代码运行所需的条件

• C# 编译器。
• Microsoft .NET Framework。
• Microsoft ODBC .NET 数据提供程序。
• PostgreSQL 数据源。

CREATE TABLE vbtest(
    id serial,
    data text,
    accessed timestamp
);
INSERT INTO csharptest(data, accessed) VALUES('Rows: 1', now());
INSERT INTO csharptest(data, accessed) VALUES('Rows: 2', now());
INSERT INTO csharptest(data, accessed) VALUES('Rows: 3', now());

代码

using System;
using System.Data;
using Microsoft.Data.Odbc;
 

class psqlODBC_Howto
{

  [STAThread]
  static void Main(string[] args)
  {

    // Setup a connection string
    string szConnect = "DSN=dsnname;" +
                       "UID=postgres;" +
                       "PWD=********";

    // Attempt to open a connection
    OdbcConnection cnDB = new OdbcConnection(szConnect);
     
    // The following code demonstrates how to catch & report an ODBC exception.
    // To keep things simple, this is the only exception handling in this example.
    // Note: The ODBC data provider requests ODBC3 from the driver. At the time of
    //       writing, the psqlODBC driver only supports ODBC2.5 - this will cause
    //       an additional error, but will *not* throw an exception.
    try 
    {
      cnDB.Open();
    } 
    catch (OdbcException ex) 
    {
      Console.WriteLine (ex.Message + "\n\n" + "StackTrace: \n\n" + ex.StackTrace);
      // Pause for the user to read the screen.
      Console.WriteLine("\nPress  to continue...");
      Console.Read();
      return;
    }
    
    // Create a dataset
    DataSet dsDB = new DataSet(); 
    OdbcDataAdapter adDB = new OdbcDataAdapter();
    OdbcCommandBuilder cbDB = new OdbcCommandBuilder(adDB);
    adDB.SelectCommand = new OdbcCommand(
                             "SELECT id, data, accessed FROM csharptest", 
                             cnDB);
    adDB.Fill(dsDB);

    // Display the record count
    Console.WriteLine("Table 'csharptest' contains {0} rows.\n", 
                      dsDB.Tables[0].Rows.Count);
    
    // List the columns (using a foreach loop)
    Console.WriteLine("Columns\n=======\n");
    
    foreach(DataColumn dcDB in dsDB.Tables[0].Columns)
      Console.WriteLine("{0} ({1})", dcDB.ColumnName, dcDB.DataType);
    Console.WriteLine("\n");

    // Iterate through the rows and display the data in the table (using a for loop).
    // Display the data column last for readability.
    Console.WriteLine("Data\n====\n");
    for(int i=0;i to continue...");
    Console.Read();
  }
}