[DUG] Blob primer

[Paul McKenzie]

We use TBlobField (We have Images we store) in the same way we use any other field...
The only difference is the setting on the TBlobField data - Assign.
The Blob subtype can be set to ftGraphic.

procedure TPhoto.FromBlob(Blob: TBlobField); //load image from file
begin
   if Assigned(Blob) then
   begin
     try
       fImage.Picture.Assign(Blob);
...

procedure TPhoto.ToBlob(Blob: TBlobField); //load image from file
begin
   if Assigned(Blob) then
   begin
     try
       Blob.Assign(fImage.Picture);
...


Regards
Paul McKenzie
SMSS Ltd.
Wellington
New Zealand


Phil Middlemiss wrote:
> I have a service running on a server that receives binary data via TCP 
> that needs to be stored in a firebird table, then retrieved later. The 
> binary data is an object. I'm hoping to get away with just using a 
> TIBSQL if I can rather than an IBQuery.
> 
> Phil.
> 
> Paul McKenzie wrote:
> 
>> What are you trying to to do?
>> How are you, or should I say, to and from what are you trying to 
>> read/write blobs data ?
>>
>> Regards
>> Paul McKenzie
>> SMSS Ltd.
>> Wellington
>> New Zealand
>>
>>
>> Phil Middlemiss wrote:
>>
>>> Thanks Paul, I'm using the blobs to store binary data, not text. I've 
>>> finally found something that covers what the subtypes are, but still 
>>> nothing that shows how to read/write to them using sql.
>>>
>>> Phil.
>>>
>>> Paul McKenzie wrote:
>>>
>>>> I don't know about firebird, but IB sux...
>>>> If you are using it for pure binary data e.g. Images etc. then there 
>>>> is not much choice, and it is usable.
>>>> Subtypes are used for defining what type of Blob data eg. Text.
>>>> If you are trying to use Blobs for storing text - My advice - avoid 
>>>> this at all costs!
>>>> Even though there is a subtype for text it is useless - we couldn't 
>>>> get SQL to interpret the text.
>>>> I ended up writing a UDF to convert our blobs out into VarChars
>>>> There are various UDF's around for dealing with Blob Text - either 
>>>> buggy or just don't work!
>>>> HTH.
>>>>
>>>> Regards
>>>> Paul McKenzie
>>>> SMSS Ltd.
>>>> Wellington
>>>> New Zealand
>>>>
>>>>
>>>> Phil Middlemiss wrote:
>>>>
>>>>> Could anyone give me a link to a "how-to" about blobs? I'm using D6 
>>>>> with firebird - there is no GUI (it's a service) so I would like to 
>>>>> just use SQL if possible.
>>>>>
>>>>> Having not used blobs before I'm wondering:
>>>>> - what is a subtype? The Interbase documentation assumes you know
>>>>> - what is a good size for the segment length
>>>>> - how to specify binary data in a sql - if it's actually possible.
>>>>> - if I can't just use sql then what's the best way?
>>>>>
>>>>> Phil.
>>>>>
>>>>> _______________________________________________
>>>>> Delphi mailing list
>>>>> Delphi at ns3.123.co.nz
>>>>> http://ns3.123.co.nz/mailman/listinfo/delphi
>>>>>
>>>>
>>>> _______________________________________________
>>>> Delphi mailing list
>>>> Delphi at ns3.123.co.nz
>>>> http://ns3.123.co.nz/mailman/listinfo/delphi
>>>>
>>>>
>>>>
>>> _______________________________________________
>>> Delphi mailing list
>>> Delphi at ns3.123.co.nz
>>> http://ns3.123.co.nz/mailman/listinfo/delphi
>>>
>>
>> _______________________________________________
>> Delphi mailing list
>> Delphi at ns3.123.co.nz
>> http://ns3.123.co.nz/mailman/listinfo/delphi
>>
>>
>>
> _______________________________________________
> Delphi mailing list
> Delphi at ns3.123.co.nz
> http://ns3.123.co.nz/mailman/listinfo/delphi
>