Enterprise Library- Data Block使用oracle存储过程，字符串参数传入值为""时出现问题的解决
Enterprise Library- Data Block使用oracle存储过程，字符串参数传入值为""时出现问题的解决 在调用存储过程时，产生如下错误：
Parameter 'p_R_URL': No size set for variable length data type: String. 说明: 执行当前 Web 请求期间，出现未处理的异常。请检查堆栈跟踪信息，以了解有关该错误以及代码中导致错误的出处的详细信息。
异常详细信息: System.Exception: Parameter 'p_R_URL': No size set for variable length data type: String.
源错误:
行 67： catch(Exception ex)行 68： {行 69： throw new Exception(ex.Message);行 70： //return false;行 71： }
源文件: c:\inetpub\wwwroot\resource\datalay\dbresource.cs 行: 69
堆栈跟踪:
[Exception: Parameter 'p_R_URL': No size set for variable length data type: String.] ReSource.DataLay.DbResource.Insert(String R_TITLE, String R_USE, String R_XKML, String R_GRLB, String R_WJLB, DateTime R_ADDTIME, String R_URL, String R_PRIVATE, String R_COMMONT) in c:\inetpub\wwwroot\resource\datalay\dbresource.cs:69 ReSource.BusLay.BusResource.Insert() in c:\inetpub\wwwroot\resource\buslay\busresource.cs:119 ReSource.WebLay.MYRESOURCEAdd.Insert(Object sender, EventArgs e) in c:\inetpub\wwwroot\resource\weblay\tjzy\myresourceadd.aspx.cs:80 System.EventHandler.Invoke(Object sender, EventArgs e) +0 System.Web.UI.WebControls.LinkButton.OnClick(EventArgs e) +108 System.Web.UI.WebControls.LinkButton.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +57 System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +18 System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +138 System.Web.UI.Page.ProcessRequestMain() +1292
版本信息: Microsoft .NET Framework 版本:1.1.4322.2300; ASP.NET 版本:1.1.4322.2300
很是郁闷，于是就打开Enterprise Library的源代码进行调试。发现问题原来出现在 OracleCommandWrapper.cs文件中的 如下函数：（从345 行开始）
private OracleParameter CreateParameter(string name, DbType dbType, int size, ParameterDirection direction, bool nullable, byte precision, byte scale, string sourceColumn, DataRowVersion sourceVersion, object value)
{
OracleParameter param = this.command.CreateParameter();
param.ParameterName = name;
param.DbType = dbType;
param.Size = size;
param.Value = (value == null) ? DBNull.Value : value;
// modify parameter type and value for special cases
switch (dbType)
{
// for Guid, change to value to byte array
case DbType.Guid:
guidParameters.Add(param.ParameterName, 'System.Guid');
param.OracleType = OracleType.Raw;
param.Size = 16;
// convert Guid value to byte array only if not null
if ((value is DBNull) || (value == null))
{
param.Value = Convert.DBNull;
}
else
{
param.Value = ((Guid)value).ToByteArray();
}
break;
// case DbType.AnsiString:
// case DbType.AnsiStringFixedLength:
// case DbType.String:
// case DbType.StringFixedLength:
// // for empty string, set it to DBNull
// if ((value == null) || (!(value is DBNull)) && ((string)value).Length == 0)
// {
// param.Value = Convert.DBNull;
// }
// break;
default:
break;
}
param.Direction = direction;
param.IsNullable = nullable;
param.Precision = precision;
param.Scale = scale;
param.SourceColumn = sourceColumn;
param.SourceVersion = sourceVersion;
return param;
}
可以看到，代码中处理了传入值为 NULL的情况。但是不知道为什么把处理字符串参数等于 '' 的时候得语句给注释掉了。于是乎，就更改源代码，如下：
private OracleParameter CreateParameter(string name, DbType dbType, int size, ParameterDirection direction, bool nullable, byte precision, byte scale, string sourceColumn, DataRowVersion sourceVersion, object value)
{
OracleParameter param = this.command.CreateParameter();
param.ParameterName = name;
param.DbType = dbType;
param.Size = size;
param.Value = (value == null) ? DBNull.Value : value;
// modify parameter type and value for special cases
switch (dbType)
{
// for Guid, change to value to byte array
case DbType.Guid:
guidParameters.Add(param.ParameterName, 'System.Guid');
param.OracleType = OracleType.Raw;
param.Size = 16;
// convert Guid value to byte array only if not null
if ((value is DBNull) || (value == null))
{
param.Value = Convert.DBNull;
}
else
{
param.Value = ((Guid)value).ToByteArray();
}
break;
case DbType.AnsiString:
case DbType.AnsiStringFixedLength:
case DbType.String:
case DbType.StringFixedLength:
// for empty string, set it to DBNull
if ((value == null) || (!(value is DBNull)) && ((string)value).Length == 0)
{
param.Value = Convert.DBNull;
}
break;
default:
break;
}
param.Direction = direction;
param.IsNullable = nullable;
param.Precision = precision;
param.Scale = scale;
param.SourceColumn = sourceColumn;
param.SourceVersion = sourceVersion;
return param;
}
问题的到了解决。但是不知道微软的代码为什么把这个给注释掉了。
后来，上网上看到Oracle 的一个论坛上的帖子上有如下的描述：
Oracle will treat '' (empty string) as
NULL, and store as NULL anyway - better be prepared for it, and
treat it as such.
版本信息: Microsoft .NET Framework 版本:1.1.4322.2300; ASP.NET 版本:1.1.4322.2300
很是郁闷，于是就打开Enterprise Library的源代码进行调试。发现问题原来出现在 OracleCommandWrapper.cs文件中的 如下函数：（从345 行开始）
private OracleParameter CreateParameter(string name, DbType dbType, int size, ParameterDirection direction, bool nullable, byte precision, byte scale, string sourceColumn, DataRowVersion sourceVersion, object value)
{
OracleParameter param = this.command.CreateParameter();
param.ParameterName = name;
param.DbType = dbType;
param.Size = size;
param.Value = (value == null) ? DBNull.Value : value;
// modify parameter type and value for special cases
switch (dbType)
{
// for Guid, change to value to byte array
case DbType.Guid:
guidParameters.Add(param.ParameterName, 'System.Guid');
param.OracleType = OracleType.Raw;
param.Size = 16;
// convert Guid value to byte array only if not null
if ((value is DBNull) || (value == null))
{
param.Value = Convert.DBNull;
}
else
{
param.Value = ((Guid)value).ToByteArray();
}
break;
// case DbType.AnsiString:
// case DbType.AnsiStringFixedLength:
// case DbType.String:
// case DbType.StringFixedLength:
// // for empty string, set it to DBNull
// if ((value == null) || (!(value is DBNull)) && ((string)value).Length == 0)
// {
// param.Value = Convert.DBNull;
// }
// break;
default:
break;
}
param.Direction = direction;
param.IsNullable = nullable;
param.Precision = precision;
param.Scale = scale;
param.SourceColumn = sourceColumn;
param.SourceVersion = sourceVersion;
return param;
}
可以看到，代码中处理了传入值为 NULL的情况。但是不知道为什么把处理字符串参数等于 '' 的时候得语句给注释掉了。于是乎，就更改源代码，如下：
private OracleParameter CreateParameter(string name, DbType dbType, int size, ParameterDirection direction, bool nullable, byte precision, byte scale, string sourceColumn, DataRowVersion sourceVersion, object value)
{
OracleParameter param = this.command.CreateParameter();
param.ParameterName = name;
param.DbType = dbType;
param.Size = size;
param.Value = (value == null) ? DBNull.Value : value;
// modify parameter type and value for special cases
switch (dbType)
{
// for Guid, change to value to byte array
case DbType.Guid:
guidParameters.Add(param.ParameterName, 'System.Guid');
param.OracleType = OracleType.Raw;
param.Size = 16;
// convert Guid value to byte array only if not null
if ((value is DBNull) || (value == null))
{
param.Value = Convert.DBNull;
}
else
{
param.Value = ((Guid)value).ToByteArray();
}
break;
case DbType.AnsiString:
case DbType.AnsiStringFixedLength:
case DbType.String:
case DbType.StringFixedLength:
// for empty string, set it to DBNull
if ((value == null) || (!(value is DBNull)) && ((string)value).Length == 0)
{
param.Value = Convert.DBNull;
}
break;
default:
break;
}
param.Direction = direction;
param.IsNullable = nullable;
param.Precision = precision;
param.Scale = scale;
param.SourceColumn = sourceColumn;
param.SourceVersion = sourceVersion;
return param;
}
问题的到了解决。但是不知道微软的代码为什么把这个给注释掉了。
后来，上网上看到Oracle 的一个论坛上的帖子上有如下的描述：
Oracle will treat '' (empty string) as
NULL, and store as NULL anyway - better be prepared for it, and
treat it as such.
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