使用 DAAB 和 C# 从 Oracle 过程返回多个引用游标
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Returning multiple ref cursors from Oracle Procedure using DAAB & C#
提问by ScottLenart
I want to return data from an Oracle procedure to populate some Label controls. The procedure accepts 26 input parameters (search variable) and returns 3 output cursors. I have been successful returning data from a procedure which returns a single ref cursor using OracleCommand, a DataAdapter, and a DataSet, but have been having all kinds of issues returning data from a procedure returning multiple ref cursors.
我想从 Oracle 过程返回数据以填充一些 Label 控件。该过程接受 26 个输入参数（搜索变量）并返回 3 个输出游标。我已经成功地从使用 OracleCommand、DataAdapter 和 DataSet 返回单个引用游标的过程返回数据，但是从返回多个引用游标的过程返回数据时遇到了各种问题。
I was trying to use DAAB from the Enterprise Library, but had no success (original post). I now have gone back to an OracleCommand based off posts from Oracle and other dev sites. I am still returning zero rows. I can return the column names from my readers using "rdr_p_cursor_detail.GetName(0);", but When I try to return a value I get a "Operation is not valid due to the current state of the object." error.
我试图使用 Enterprise Library 中的 DAAB，但没有成功（原始帖子）。我现在已经回到基于来自 Oracle 和其他开发站点的帖子的 OracleCommand。我仍然返回零行。我可以使用“rdr_p_cursor_detail.GetName(0);”从我的读者那里返回列名，但是当我尝试返回一个值时，我得到一个“由于对象的当前状态，操作无效”。错误。
//Open the connection to Oracle.
OracleConnection cn = new OracleConnection(ConfigurationHelper.ConnectionStringSlabProcedures);
OracleCommand cmd = new OracleCommand();
cn.Open();
cmd.Connection = cn;
try
{
//Set the command text (SQL) of the Oracle command to the stored procedure "getSlab", which returns slab details.
cmd.CommandText = ConfigurationHelper.ProcuedurePackageSchema + "." +
ConfigurationHelper.ProcuedurePackageName + "." +
"getSlab";
//...and specify the command as a stored procedure.
cmd.CommandType = CommandType.StoredProcedure;
//Add the input and output parameters.
cmd.Parameters.Add("rb_category", OracleDbType.Varchar2).Value = string.Empty;
cmd.Parameters.Add("rb_category_value", OracleDbType.Varchar2).Value = slabID;
cmd.Parameters.Add("rb_type ", OracleDbType.Varchar2).Value = string.Empty;
cmd.Parameters.Add("rb_chem_value", OracleDbType.Varchar2).Value = string.Empty;
cmd.Parameters.Add("cb_inside_only", OracleDbType.Varchar2).Value = string.Empty;
cmd.Parameters.Add("cb_appl_pending", OracleDbType.Varchar2).Value = string.Empty;
cmd.Parameters.Add("cb_appl_soft_approved", OracleDbType.Varchar2).Value = string.Empty;
cmd.Parameters.Add("cb_appl_hard_approved", OracleDbType.Varchar2).Value = string.Empty;
cmd.Parameters.Add("cb_appl_mechanically", OracleDbType.Varchar2).Value = string.Empty;
cmd.Parameters.Add("cb_as_cast", OracleDbType.Varchar2).Value = string.Empty;
cmd.Parameters.Add("cb_as_dispoed", OracleDbType.Varchar2).Value = string.Empty;
cmd.Parameters.Add("cb_chem_match", OracleDbType.Varchar2).Value = string.Empty;
cmd.Parameters.Add("cb_near_match", OracleDbType.Varchar2).Value = string.Empty;
cmd.Parameters.Add("txt_width_min", OracleDbType.Int32).Value = 0;
cmd.Parameters.Add("txt_width_max", OracleDbType.Int32).Value = 0;
cmd.Parameters.Add("txt_quality_min", OracleDbType.Int32).Value = 0;
cmd.Parameters.Add("txt_quality_max", OracleDbType.Int32).Value = 0;
cmd.Parameters.Add("txt_days_old_min", OracleDbType.Int32).Value = 0;
cmd.Parameters.Add("txt_days_old_max", OracleDbType.Int32).Value = 0;
cmd.Parameters.Add("txt_days_rev_min", OracleDbType.Int32).Value = 0;
cmd.Parameters.Add("txt_days_rev_max", OracleDbType.Int32).Value = 0;
cmd.Parameters.Add("txt_reviewer", OracleDbType.Varchar2).Value = string.Empty;
cmd.Parameters.Add("cb_excl_hr", OracleDbType.Varchar2).Value = string.Empty;
cmd.Parameters.Add("cb_excl_cr", OracleDbType.Varchar2).Value = string.Empty;
cmd.Parameters.Add("cb_excl_galv", OracleDbType.Varchar2).Value = string.Empty;
cmd.Parameters.Add("cb_excl_tin", OracleDbType.Varchar2).Value = string.Empty;
//Add the ref-cursors as output parameters
OracleParameter p_cursor_detail = cmd.Parameters.Add("p_cursor_detail", OracleDbType.RefCursor);
p_cursor_detail.Direction = ParameterDirection.Output;
OracleParameter p_cursor_comments = cmd.Parameters.Add("p_cursor_comments", OracleDbType.RefCursor);
p_cursor_comments.Direction = ParameterDirection.Output;
OracleParameter p_cursor_grades = cmd.Parameters.Add("p_cursor_grades", OracleDbType.RefCursor);
p_cursor_grades.Direction = ParameterDirection.Output;
// Execute the command
cmd.ExecuteNonQuery();
// Construct an OracleDataReader from the REF CURSOR
OracleDataReader rdr_p_cursor_detail = ((OracleRefCursor)p_cursor_detail.Value).GetDataReader();
if (rdr_p_cursor_detail.Read())
{
//This would return an error if it was outside this if statement.
//"Operation is not valid due to the current state of the object."
OracleString oracleString1 = rdr_p_cursor_detail.GetOracleString(1);
LabelSlabID.Text = oracleString1.ToString();
//This correctly returns column name/header.
//LabelSlabID.Text = rdr_p_cursor_detail.GetName(0);
}
else
{
LabelSlabID.Text = "No Data";
}
rdr_p_cursor_detail.Close();
rdr_p_cursor_detail.Dispose();
p_cursor_detail.Dispose();
p_cursor_comments.Dispose();
p_cursor_grades.Dispose();
}
catch (Exception e)
The truncated oracle procedure:
截断的oracle程序：
PROCEDURE getSlab
(rb_category IN VARCHAR2
,rb_category_value IN VARCHAR2
,rb_type IN VARCHAR2
,rb_chem_value IN VARCHAR2
,cb_inside_only IN VARCHAR2
,cb_appl_pending IN VARCHAR2
,cb_appl_soft_approved IN VARCHAR2
,cb_appl_hard_approved IN VARCHAR2
,cb_appl_mechanically IN VARCHAR2
,cb_as_cast IN VARCHAR2
,cb_as_dispoed IN VARCHAR2
,cb_chem_match IN VARCHAR2
,cb_near_match IN VARCHAR2
,txt_width_min IN NUMBER
,txt_width_max IN NUMBER
,txt_quality_min IN NUMBER
,txt_quality_max IN NUMBER
,txt_days_old_min IN NUMBER
,txt_days_old_max IN NUMBER
,txt_days_rev_min IN NUMBER
,txt_days_rev_max IN NUMBER
,txt_reviewer IN VARCHAR2
,cb_excl_hr IN VARCHAR2
,cb_excl_cr IN VARCHAR2
,cb_excl_galv IN VARCHAR2
,cb_excl_tin IN VARCHAR2
,cur_OUT OUT t_cursor1
,cur_OUT1 OUT t_cursor2
,cur_OUT2 OUT t_cursor3) IS
--All the queries and so forth are performed and data sent to temp tables.
OPEN v_cursor1 FOR
SELECT * FROM TABLE(CAST(g_slab_table AS getSlab_table));
cur_OUT := v_cursor1;
OPEN v_cursor2 FOR
SELECT * FROM TABLE(CAST(g_comment_table AS getComment_table));
cur_OUT1 := v_cursor2;
OPEN v_cursor3 FOR
SELECT * FROM TABLE(CAST(g_grades_table AS getGrades_table));
cur_OUT2 := v_cursor2;
Any ideas? I'm leaning towards improper reader use, but can't figure out what I'm missing. Thanks.
有任何想法吗？我倾向于不正确的读者使用，但无法弄清楚我错过了什么。谢谢。
采纳答案by ScottLenart
It appears to be the Oracle stored procedure. I modified the cursor output, hard-coding a selection from "dual", and the data and column headers are coming back good.
它似乎是 Oracle 存储过程。我修改了光标输出，从“双”中硬编码了一个选择，数据和列标题恢复正常。
So...
所以...
Lesson 1) If you receive an error "Operation is not valid due to the current state of the object", your connection is closed or there are no rows of data being returned.
第 1 课) 如果您收到错误“由于对象的当前状态，操作无效”，则您的连接已关闭或没有返回任何数据行。
Lesson 2) Don't trust your procedure writers (if you aren't writing the db code yourself). Take the 30 minutes to review their code if you think your code should work. It can save you a dozen or so wasted hours :).
第 2 课）不要相信您的程序编写者（如果您不是自己编写数据库代码）。如果您认为您的代码应该可以工作，请花 30 分钟查看他们的代码。它可以为您节省十几个小时的浪费:)。
Thanks all.
谢谢大家。
回答by Kryptos
I've been through almost the same scenario... The main problem was that there were no rows of data being returned. That can be checked by using:
我经历过几乎相同的场景......主要问题是没有返回任何行数据。可以使用以下方法进行检查：
if(reader.HasRows)
The other thing that solved my problem was the use of
解决我的问题的另一件事是使用
reader.NextResult()
to get to the next returned (out) cursor.
到达下一个返回的（出）游标。
