【下載dotConnect for Oracle最新版本】

dotConnect for Oracle(原名OraDirect.NET)建立在ADO.NET技術(shù)上，為基于Oracle數(shù)據(jù)庫(kù)的應(yīng)用程序提供完整的解決方案。它為設(shè)計(jì)應(yīng)用程序結(jié)構(gòu)帶來(lái)了新的方法，提高工作效率，使數(shù)據(jù)庫(kù)應(yīng)用程序的開發(fā)更簡(jiǎn)便。

檢索和修改數(shù)據(jù)

• 介紹
• 要求
• 一般信息
• 使用連接的模型檢索和更新數(shù)據(jù)
• 使用斷開連接的模型檢索和更新數(shù)據(jù)
• 附加信息

介紹

本教程介紹如何使用OracleCommand、OracleDataReader和OracleDataTable組件。

要求

本教程假設(shè)您知道如何連接到服務(wù)器，如何在服務(wù)器上創(chuàng)建必要的對(duì)象，以及如何將數(shù)據(jù)插入到創(chuàng)建的表中。

請(qǐng)注意，如果您不使用設(shè)計(jì)時(shí)（特別是，如果您不從工具箱放置在設(shè)計(jì)器或OracleConnection組件上），則必須手動(dòng)嵌入許可證信息。

一般信息

如我們所知，任何數(shù)據(jù)庫(kù)應(yīng)用程序的原始功能都是建立到數(shù)據(jù)源的連接，并處理其中包含的數(shù)據(jù)。ADO.NET的.NET框架數(shù)據(jù)提供程序充當(dāng)應(yīng)用程序和數(shù)據(jù)源之間的橋梁，允許您執(zhí)行命令以及使用DataReader或DataAdapter檢索數(shù)據(jù)。更新數(shù)據(jù)涉及到使用命令和數(shù)據(jù)適配器對(duì)象；它還可能涉及使用事務(wù)。

讓我們進(jìn)行一些分類，以便更好地理解ADO.NET模型。使用數(shù)據(jù)有兩種方法：連接和斷開連接的模型。您可以使用連接模型的類來(lái)建立連接和設(shè)置事務(wù)、獲取數(shù)據(jù)和更新數(shù)據(jù)源。這些類直接與數(shù)據(jù)庫(kù)交互：oracleProviderFactory、oracleConnection、oracleTransaction、oracleDataAdapter、oracleCommand、oracleParameter和oracleDataReader。

這些對(duì)象表示ADO.NET的斷開連接的模型，不會(huì)立即與數(shù)據(jù)源進(jìn)行互操作。這些類提供了脫機(jī)處理數(shù)據(jù)存儲(chǔ)的能力：數(shù)據(jù)集、數(shù)據(jù)表、數(shù)據(jù)列、數(shù)據(jù)行、約束、數(shù)據(jù)關(guān)系、數(shù)據(jù)視圖和數(shù)據(jù)行視圖。

我們將在示例中使用兩個(gè)模型中的類。

本教程的目標(biāo)是從table dept檢索和更新數(shù)據(jù)（適當(dāng)?shù)腄DL/DML腳本位于\Program Files\Devart\dotConnect\Oracle\Samples\tables.sql——用于dotConnect for Oracle的默認(rèn)路徑）。

使用連接的模型檢索和更新數(shù)據(jù)

在本示例中，我們使用OracleCommand和 OracleDataReader來(lái)檢索和操作數(shù)據(jù)。

using Devart.Data.Oracle;
...
class Program
{
    void PrintDept(OracleConnection connection)
    {
        OracleCommand command = connection.CreateCommand();
        command.CommandText = "select * from dept";
        
        // Call the Close method when you are finished using the OracleDataReader 
        // to use the associated OracleConnection for any other purpose.
        // Or put the reader in the using block to call Close implicitly.
        using (OracleDataReader reader = command.ExecuteReader())
        {
            // printing the column names
            for (int i = 0; i < reader.FieldCount; i++)
                Console.Write(reader.GetName(i).ToString() + "\t");
            Console.Write(Environment.NewLine);
            // Always call Read before accesing data
            while (reader.Read())
            {
                // printing the table content
                for (int i = 0; i < reader.FieldCount; i++)
                    Console.Write(reader.GetValue(i).ToString() + "\t");
                Console.Write(Environment.NewLine);
            }
        }
    }
    
    void ModifyDept(OracleConnection connection)
    {
        OracleCommand command = connection.CreateCommand();
        command.CommandText = "UPDATE DEPT SET LOC='VEGAS' WHERE DEPTNO > 20";
        
        // return value of ExecuteNonQuery (i) is the number of rows affected by the command
        int i = command.ExecuteNonQuery();
        Console.WriteLine(Environment.NewLine + "Rows in DEPT updated: {0}", i + Environment.NewLine);
    }
    
    static void Main(string[] args)
    {
        using (OracleConnection conn 
            = new OracleConnection("User Id=Scott;Password=tiger;Data Source=Ora;"))
        {
            try
            {
                conn.Open();
                Program program = new Program();
                
                // printing out the Dept table to console
                program.PrintDept(conn);
                
                // updating records in Dept
                program.ModifyDept(conn);
                
                // printing out the Dept table to console
                program.PrintDept(conn);
            }
            catch (OracleException ex)
            {
                Console.WriteLine("Exception occurs: {0}", ex.Message);
            }
            finally
            {
                Console.ReadLine();
            }
        }
    }
}

Imports Devart.Data.Oracle
...
Module Module1
    Sub PrintDept(ByVal connection As OracleConnection)
        Dim command As OracleCommand = connection.CreateCommand()
        command.CommandText = "select * from dept"
        
        ' Call the Close method when you are finished using the OracleDataReader 
        ' to use the associated OracleConnection for any other purpose.
        ' Or put the reader in the using block to call Close implicitly.
        Using reader As OracleDataReader = command.ExecuteReader()
            ' printing the column names
            For i As Integer = 0 To reader.FieldCount - 1
                Console.Write(reader.GetName(i).ToString() & VbCrlf)
            Next i
            Console.Write(Environment.NewLine)
            
            ' Always call Read before accesing data
            While reader.Read()
                ' printing the table content
                For i As Integer = 0 To reader.FieldCount - 1
                    Console.Write(reader.GetValue(i).ToString() & VbCrlf)
                Next
                Console.Write(Environment.NewLine)
            End While
        End Using
    End Sub

    Sub ModifyDept(ByVal connection As OracleConnection)
        Dim command As OracleCommand = connection.CreateCommand()
        command.CommandText = "UPDATE DEPT SET LOC='VEGAS' WHERE DEPTNO > 20"
        
        ' return value of ExecuteNonQuery (i) is the number of rows affected by the command
        Dim i As Integer = command.ExecuteNonQuery()
        Console.WriteLine(Environment.NewLine & "Rows in DEPT updated: {0}", i & Environment.NewLine)
    End Sub

    Sub Main()
        Using conn _
            As New OracleConnection("User Id=Scott;Password=tiger;Data Source=Ora;")
            Try
                conn.Open()
                
                ' printing out the Dept table to console
                Module1.PrintDept(conn)
                
                ' updating records in Dept
                Module1.ModifyDept(conn)
                
                ' printing out the Dept table to console
                Module1.PrintDept(conn)
            Catch ex As OracleException
                Console.WriteLine("Exception occurs: {0}", ex.Message)
            Finally
                Console.ReadLine()
            End Try
        End Using
    End Sub
End Module

使用斷開連接的模型檢索和更新數(shù)據(jù)

使用數(shù)據(jù)表和數(shù)據(jù)集的傳統(tǒng)方法假定連續(xù)創(chuàng)建和初始化連接、命令、數(shù)據(jù)適配器和commandbuilder對(duì)象。Devart OracleDataTable和OracleDataset具有高級(jí)功能，可以更輕松地處理數(shù)據(jù)。更重要的是，使用我們的組件，您可以在設(shè)計(jì)時(shí)檢索和操作數(shù)據(jù)。

下面是一個(gè)演示OracleDataTable用法的小示例。

public void UseDataTable()
{
   OracleDataTable myDataTable 
    = new OracleDataTable("SELECT * FROM Dept", "User Id=Scott;Password=tiger;Data Source=Ora;");
   try
   {
       // FetchAll=true means to retrieve data from server entirely when DataTable is opened.
       //  By default, FetchAll is set to false - only minimal quantity of rows is requested at once,
       //  which leads to better initial response time and less network traffic.
       myDataTable.FetchAll = true;
     
       // populating DataTable with data from data source
       myDataTable.Active = true;
     
       // modifying the third record
       myDataTable.Rows[3]["DName"] = "Researches";
     
       // Update method executes the appropriate commands (delete, insert, or update) in the data source.
       Console.WriteLine(myDataTable.Update() + " rows updated.");
       
       // printing the DataTable content
       foreach (DataRow myRow in myDataTable.Rows)
       {
          foreach (DataColumn myCol in myDataTable.Columns)
          {
              Console.Write(myRow[myCol] + "\t");
          }
          Console.WriteLine();
       }
     }
     finally
     {
        //Active=false does not clear the data, but frees the resources allocated on the server, if any.
        myDataTable.Active = false;
     }
}

Public Sub UseDataTable()
    Dim myDataTable As OracleDataTable _
        As New OracleDataTable("SELECT * FROM Dept", "User Id=Scott;Password=tiger;Data Source=Ora;")
    Try
        ' FetchAll=true means to retrieve data from server entirely when DataTable is opened.
        '  By default, FetchAll is set to false - only minimal quantity of rows is requested at once,
        '  which leads to better initial response time and less network traffic.
        myDataTable.FetchAll = True
        
        ' populating DataTable with data from data source
        myDataTable.Active = True
        
        ' modifying the third record
        myDataTable.Rows(3)("DName") = "Researches"
        
        ' Update method executes the appropriate commands (delete, insert, or update) in the data source.
        Console.WriteLine(myDataTable.Update() & " rows updated.")
        Dim myRow As DataRow
        Dim myCol As DataColumn
        
        ' printing the DataTable content
        For Each myRow In myDataTable.Rows
            For Each myCol In myDataTable.Columns
                Console.Write(myRow(myCol) & VbCrlf)
            Next myCol
            Console.WriteLine()
        Next myRow
    Finally
        ' Active=false does not clear the data, but frees the resources allocated on the server, if any.
        myDataTable.Active = False
    End Try
End Sub

使用Devart數(shù)據(jù)集向?qū)Э梢暂p松創(chuàng)建OracleDataset，并使用Devart數(shù)據(jù)集管理器進(jìn)行可視化管理。

附加信息

本教程只介紹處理數(shù)據(jù)的基本方法。此外，還可以利用存儲(chǔ)過(guò)程、類型化數(shù)據(jù)集和ORM解決方案。Dotconnect for Oracle支持LinqConnect和實(shí)體框架ORM技術(shù)，用于在關(guān)系數(shù)據(jù)庫(kù)中的不兼容類型系統(tǒng)和面向?qū)ο缶幊陶Z(yǔ)言之間轉(zhuǎn)換數(shù)據(jù)。這些技術(shù)允許您減少面向數(shù)據(jù)應(yīng)用程序所需的代碼和維護(hù)量。

購(gòu)買dotConnect for Oracle正版授權(quán)的朋友可以點(diǎn)擊""哦~~~