11

I'm trying to get the output from the DBMS_OUTPUT.PUT_LINE() method in my anonymous PL/SQL block through C#. I've looked at a couple of other related questions here, but am still having trouble. The return code of executing the anonymous block is returning -1, which should be correct based on the docs.

I'm setting the DBMS_OUTPUT.ENABLE() to NULL in order to not set a specific buffer size, then using the DBMS_OUTPUT.GET_LINES() method in order to get the lines from that buffer.

It returns nothing in the buffer (An empty OracleString[]) and returns 0 lines. My anonymous PL/SQL block is simple like this, but should work for any.

DECLARE
    lvsName VARCHAR2(6) := 'Oracle';
BEGIN
    DBMS_OUTPUT.PUT_LINE('Do you see me?');
    DBMS_OUTPUT.PUT_LINE('My name is: ' || lvsName);    
END;

What am I missing?

using (OracleDataAdapter oda = new OracleDataAdapter())
using (OracleCommand cmd = new OracleCommand(sql, _connection))
{
    // Execute anonymous PL/SQL block
    cmd.CommandType = CommandType.Text;
    var res = cmd.ExecuteNonQuery();

    // Set output Buffer
    cmd.CommandText = "BEGIN DBMS_OUTPUT.ENABLE(NULL); END;";
    cmd.CommandType = CommandType.Text;
    cmd.ExecuteNonQuery();

    // Get output
    cmd.CommandText = "BEGIN DBMS_OUTPUT.GET_LINES(:outString, :numLines); END;";
    cmd.CommandType = CommandType.Text;
    cmd.Parameters.Clear();
    cmd.Parameters.Add(new OracleParameter("outString", OracleDbType.Varchar2, int.MaxValue, ParameterDirection.Output));
    cmd.Parameters["outString"].CollectionType = OracleCollectionType.PLSQLAssociativeArray;
    cmd.Parameters["outString"].Size = sql.Length;
    cmd.Parameters["outString"].ArrayBindSize = new int[sql.Length];
    cmd.Parameters.Add(new OracleParameter("numLines", OracleDbType.Int32, ParameterDirection.InputOutput));
    cmd.Parameters["numLines"].Value = 10; // Get 10 lines
    cmd.ExecuteNonQuery();

     int numLines = Convert.ToInt32(cmd.Parameters["numLines"].Value.ToString());
     string outString = string.Empty;

     // Try to get more lines until there are zero left
     while (numLines > 0)
     {
         for (int i = 0; i < numLines; i++)
         {
             OracleString s = (OracleString)cmd.Parameters["outString"].Value;
             outString += s.ToString();
         }

         cmd.ExecuteNonQuery();
         numLines = Convert.ToInt32(cmd.Parameters["numLines"].Value.ToString());
     }

     return outString;
}
4

4 回答 4

8

您的代码的主要问题是它没有为输出缓冲区的每个元素设置绑定大小。检索结果时，它也没有正确索引输出缓冲区。最后，执行顺序也起作用：在执行匿名代码块之前，您必须首先启用输出。所做的每一项更改都在以下MCVE中进行了注释。仅进行了必要的更改以使其正常工作。

static void Main(string[] args)
{
    string str = "User Id=xxx; password=xxx; Data Source=localhost:1521/xxx;";
    string sql = @"DECLARE lvsName VARCHAR2(6) := 'Oracle'; BEGIN  DBMS_OUTPUT.PUT_LINE('Do you see me?'); DBMS_OUTPUT.PUT_LINE('My name is: ' || lvsName); END;";

    OracleConnection _connection = new OracleConnection(str);

    try
    {
        _connection.Open();

        //adapter not being used
        //using (OracleDataAdapter oda = new OracleDataAdapter())

        using (OracleCommand cmd = new OracleCommand(sql, _connection))
        {
            // First enable buffer output
            // Set output Buffer
            cmd.CommandText = "BEGIN DBMS_OUTPUT.ENABLE(NULL); END;";
            cmd.CommandType = CommandType.Text;
            cmd.ExecuteNonQuery();

            // Then execute anonymous block
            // Execute anonymous PL/SQL block
            cmd.CommandText = sql;
            cmd.CommandType = CommandType.Text;
            var res = cmd.ExecuteNonQuery();


            // Get output
            cmd.CommandText = "BEGIN DBMS_OUTPUT.GET_LINES(:outString, :numLines); END;";
            cmd.CommandType = CommandType.Text;

            cmd.Parameters.Clear();

            cmd.Parameters.Add(new OracleParameter("outString", OracleDbType.Varchar2, int.MaxValue, ParameterDirection.Output));
            cmd.Parameters["outString"].CollectionType = OracleCollectionType.PLSQLAssociativeArray;
            cmd.Parameters["outString"].Size = sql.Length;
            cmd.Parameters["outString"].ArrayBindSize = new int[sql.Length];

            // set bind size for each array element
            for (int i = 0; i < sql.Length; i++)
            {
                cmd.Parameters["outString"].ArrayBindSize[i] = 32000;
            }


            cmd.Parameters.Add(new OracleParameter("numLines", OracleDbType.Int32, ParameterDirection.InputOutput));
            cmd.Parameters["numLines"].Value = 10; // Get 10 lines
            cmd.ExecuteNonQuery();

            int numLines = Convert.ToInt32(cmd.Parameters["numLines"].Value.ToString());
            string outString = string.Empty;

            // Try to get more lines until there are zero left
            while (numLines > 0)
            {
                for (int i = 0; i < numLines; i++)
                {
                    // use proper indexing here
                    //OracleString s = (OracleString)cmd.Parameters["outString"].Value;
                    OracleString s = ((OracleString[])cmd.Parameters["outString"].Value)[i];
                    outString += s.ToString();

                    // add new line just for formatting
                    outString += "\r\n";
                }

                cmd.ExecuteNonQuery();
                numLines = Convert.ToInt32(cmd.Parameters["numLines"].Value.ToString());
            }

            Console.WriteLine(outString);
        }
    }
    catch (Exception ex)
    {
        Console.WriteLine(ex.ToString());
    }

    _connection.Close();
    _connection.Dispose();

    Console.WriteLine("Press RETURN to exit.");
    Console.ReadLine();
}

输出结果是：

Do you see me?
My name is: Oracle

Press RETURN to exit.
于 2018-12-03T03:17:18.617 回答
4

感谢 jsanalytics 的上述回答，它为解决方案提供了良好的基础。但是，上述解决方案存在一些问题，主要与在许多没有意义的地方使用 sql.Length 有关。这是一个可重用的解决方案，可以纠正一些问题。

using Oracle.DataAccess.Client;
using Oracle.DataAccess.Types;
using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;

namespace MyNamespace
{
    public static class DbmsOutputHelper
    {
        public const int DefaultReadBatchSize = 10;

        public static void EnableDbmsOutput(this OracleConnection conn)
        {
            using (var cmd = conn.CreateCommand())
            {
                cmd.CommandText = "DBMS_OUTPUT.ENABLE";
                cmd.CommandType = CommandType.StoredProcedure;
                cmd.ExecuteNonQuery();
            }
        }

        public static void DisableDbmsOutput(this OracleConnection conn)
        {
            using (var cmd = conn.CreateCommand())
            {
                cmd.CommandText = "DBMS_OUTPUT.DISABLE";
                cmd.CommandType = CommandType.StoredProcedure;
                cmd.ExecuteNonQuery();
            }
        }

        public static List<string> ReadDbmsOutput(this OracleConnection conn, int readBatchSize = DefaultReadBatchSize)
        {
            if (readBatchSize <= 0)
            {
                throw new ArgumentOutOfRangeException(nameof(readBatchSize), "must be greater than zero");
            }

            using (var cmd = conn.CreateCommand())
            {
                cmd.CommandText = "DBMS_OUTPUT.GET_LINES";
                cmd.CommandType = CommandType.StoredProcedure;

                var linesParam = cmd.Parameters.Add(new OracleParameter("lines", OracleDbType.Varchar2, int.MaxValue, ParameterDirection.Output));
                linesParam.CollectionType = OracleCollectionType.PLSQLAssociativeArray;
                linesParam.Size = readBatchSize;
                linesParam.ArrayBindSize = Enumerable.Repeat(32767, readBatchSize).ToArray();   // set bind size for each array element

                var numLinesParam = cmd.Parameters.Add(new OracleParameter("numlines", OracleDbType.Int32, ParameterDirection.InputOutput));

                var result = new List<string>();
                int numLinesRead;

                do
                {
                    numLinesParam.Value = readBatchSize;
                    cmd.ExecuteNonQuery();
                    numLinesRead = ((OracleDecimal)numLinesParam.Value).ToInt32();

                    var values = (OracleString[])linesParam.Value;

                    for (int i = 0; i < numLinesRead; i++)
                    {
                        result.Add(values[i].ToString());
                    }

                } while (numLinesRead == readBatchSize);

                return result;
            }
        }
    }
}
于 2019-12-10T13:11:52.197 回答
2

在我看来，您的操作顺序错误...

// Execute anonymous PL/SQL block
cmd.CommandType = CommandType.Text;
var res = cmd.ExecuteNonQuery();

// Set output Buffer
cmd.CommandText = "BEGIN DBMS_OUTPUT.ENABLE(NULL); END;";
cmd.CommandType = CommandType.Text;
cmd.ExecuteNonQuery();

// Get output
cmd.CommandText = "BEGIN DBMS_OUTPUT.GET_LINES(:outString, :numLines); END;";

在设置（启用）DBMS_OUTPUT和获取输出之间GET_LINES应该是你的写命令，但相反，它是你执行的第一件事。

尝试更改顺序。让我知道它是否有效，因为我没有尝试过（我不习惯 C#...我在 Java 中有它）。

于 2018-11-26T13:52:48.567 回答
1

我不会说 C#，但我没有在您的代码中看到您为 numLines 变量赋值的位置。

  DBMS_OUTPUT.GET_LINES (
   lines       OUT     CHARARR,
   numlines    IN OUT  INTEGER);

plsql 中的示例：

DECLARE
   v_array       DBMS_OUTPUT.CHARARR;
   v_lines   NUMBER;
BEGIN
   DBMS_OUTPUT.PUT_LINE ('aaaaa');
   DBMS_OUTPUT.put_line ('bbbb');
   DBMS_OUTPUT.put_line ('ccccc');
   v_lines := 1000; -- Number of lines you want to retrieve from the buffer.  
   DBMS_OUTPUT.GET_LINES (v_array, v_lines);

   DBMS_OUTPUT.put_line(v_lines); -- Lines retrieved from buffer.
   FOR idx IN nvl(v_array.FIRST,1) .. nvl(v_array.LAST,-1)
   LOOP
      DBMS_OUTPUT.put_line (v_array (idx));
   END LOOP;
END;
于 2018-11-21T12:08:38.670 回答