2b616b15
XPost: microsoft.public.dotnet.languages.csharp
From: arne@vajhoej.dk
On 31-07-2010 21:41, Joe Cool wrote:
> On Jul 31, 9:21 pm, Arne Vajhøj wrote:
>> On 31-07-2010 20:50, Joe Cool wrote:
>>> On Jul 31, 8:41 pm, Arne Vajhøj wrote:
>>>> On 31-07-2010 20:39, Joe Cool wrote:
>>>>> On Jul 31, 8:37 pm, Arne Vajhøj wrote:
>>>>>> On 31-07-2010 20:29, Joe Cool wrote:
>>
>>>>>>> On Jul 31, 8:02 pm, Arne Vajhøj wrote:
>>>>>>>> On 31-07-2010 19:36, Joe Cool wrote:
>>
>>>>>>>>> I am cross posting this request for help in both the C#,NET and the
>>>>>>>>> SQLServer newsgroups in he hope that some reader of one these
>>>>>>>>> newsgroups can offer some help.
>>
>>>>>>>>> I am well aware that the image datatype (as well as others) are being
>>>>>>>>> phased out in some future version of SQL Server. For that reason, in
>>>>>>>>> all of my personal C#.NET projects that store images use the
>>>>>>>>> varbinary(max) datatype.
>>
>>>>>>>>> I am in the process of converting a VB.NET project that I use for
>>>>>>>>> consulting work with a former (and hopefully soon to be repeat)
>>>>>>>>> employer tp C#.NET. When originally designed, their software was
based
>>>>>>>>> on SQL7. Currently their software supports SQL2005. One key table in
>>>>>>>>> their database is a table of images and (not sure if it still does)
>>>>>>>>> but legacy databases utilize the image datatype to store images. With
>>>>>>>>> SQL7 I used a SQL command line utility called TEXTCOPY to extract the
>>>>>>>>> binary content of image columns to a JPG file.
>>
>>>>>>>>> This utility needs to be able to extract these images to external
>>>>>>>>> files even for legacy databases that may still use the image
datatype.
>>>>>>>>> But I find that the technique I use to extract images from a
>>>>>>>>> varbinary(max) column doesn't work for image datatypes. And I see
that
>>>>>>>>> SQL2005, while it still supports image datatype, the TEXTCOPY utility
>>>>>>>>> is nowhere to be found.
>>
>>>>>>>>> Any ideas on how to extract image data types from a SQL2005 database
>>>>>>>>> with C#.NET?
>>
>>>>>>>> Have you tried the obvious: SqlConnection, SqlCommand, SELECT,
>>>>>>>> ExecuteReader, SqlDataReader og læse kolonnen som byte[] ?
>>
>>>>>>> Here is what I am using that works with varbinary(max) datatype
>>>>>>> columns.
>>
>>>>>>> SqlCommand cmd;
>>>>>>> SqlDataReader rdr;
>>>>>>> DataTable dataTable;
>>
>>>>>>> cmd = new SqlCommand("select imagecolumn, linkcolumn from images",
>>>>>>> cn)'
>>>>>>> rdr = cmd.ExecuteReader();
>>>>>>> dataTable.Load(rdr);
>>
>>>>>> Drop the data table and try:
>>
>>>>>> while(rdr.Read())
>>>>>> {
>>>>>> byte[] image = (byte[])rdr[0];
>>>>>> string link = (string)rdr[1];
>>>>>> // process image and link
>>
>>>>>> }
>>
>>>>> Umm, so are you saying that while the datatable works with a
>>>>> varbinary(max) datatype, for an image datatype I should drop the
>>>>> datatable and just use a data reader?
>>
>>>> I don't know if the data table is the problem.
>>
>>>> I know that the reader will work.
>>
>>>> And according to your description, then you don't need
>>>> the data table.
>>
>>>> So it is worth a try.
>>
>>> The only reason I was trying to use a data table is because I am using
>>> a support class library (that I also wrote) that returns data using
>>> just a datatable. I suppose I can enhance it to also support returning
>>> data with a data reader.
>>
>> What is the problem when you try getting the image with the
>> current code?
>
> The extracted files are smaller than the JPGs extracted by the VB.NET
> version and are not valid JPG files (their content is not the same).
Is the size in the DB correct?
If yes - is the size in the data table correct?
Arne
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