Problem with Devart 7.7.226.0

[sathish]

We've purchased devart 7.7.226.0 last month. When we trying to update char(1) column value as empty character('') via visual studio 2010 vb.net, the table's column has been wrongly updated the undefined symbol instead of null value.

Note: Previously we've version devart 5.0, due to the database migration from oracle 10g to 11g we've purchased this new devart version 7.7.226.0.

Operating system: windows server 2003
IIS: version 6.0
Database: Oracle 11g version 11.2.0
Frontend: Visual studio 2010 professional edition.

Can anyone share your suggestions?

Regards,
Sathish

[Pinturiccio]

We could not reproduce the issue. Please send us a snippet of code with:
1. OracleConnection creation (roughly, without credentials);
2. OracleCommand creation for an insert or update statement;
3. Parameters creation, if they are used in your OracleCommand.

Please also send us the DDL script for creating your test table. A test project would be helpful.

[sathish]

Thanks for your reply, I've send my sample project which is a Visual studio 2010 vb.net solution to support at devart dot com . And also the backend scripts for OracleConnection (without credentials), OracleCommand and Parameters are attached as sql and text files in the same folder itself.

Kindly look into this issue and revert.

Thanks & Regards,
Sathish.J | Software Engineer

[Pinturiccio]

We have reproduced the issue. We will investigate it and notify you about the results as soon as possible.
As a temporary workaround, replace the following line in your code:

Code: Select all

Dim flag As Char = txtflag.Text.ToString()

with this one:

Code: Select all

Dim flag As String = txtflag.Text.ToString()

[sathish]

Thanks, Yes we've already implemented that workaround in our system and its working fine. We're looking forward your solution.

Regards,
Sathish.J

[Pinturiccio]

The described behavior is designed. System.Char type in .NET Framework cannot contain empty values as opposed to the System.String type. An uninitialized variable of the System.Char type stores a character with the zero number.

In Oracle the CHAR(1) type can store a character with the zero number. Then the following query:

Code: Select all

SELECT * FROM devtest WHERE flag IS not null

will not return the required records, but the following query:

Code: Select all

SELECT * FROM devtest WHERE flag = CHR(00)

will return the required records.

In Visual Basic, conversion from the System.String to the System.Char type is performed implicitly, without any validations. If you perform an explicit conversion of an empty string to the System.Char type, you will get an exception:

Code: Select all

Dim flag as Char = Char.Parse(stringVariable) 'If stringVariable is empty string ("") then the exception will be thrown