How about using one table -
- Name TEXT
- Birthdate REAL
- Mimetype TEXT
- Image BLOB
The mimetype column tells you the image type (jpeg etc).
One access would be SELECT Name Birthdate Mimetype FROM Yourtab. It
would not access the BLOB.
Stef Mientki wrote:
Cesar Rodas wrote:
Save into a blob.
thanks but that's not what I meant.
I'll try to explain with an example:
I want to create this database
Persons
- Name
- Birthday
- Picture
Now when I want to view this database with a general database browser /
manager,
I'll first find out what tables there are in this database,
Secondly I'm going to ask for an overview of each table by, that will be
displayed in a flat table (2-dimensional matrix)
SELECT * FROM Persons
Now the browser sees the blob field at displays is something like "{blob}"
So I assume, that the browser get's all the data, including all the bits
and bytes of each image in each record,
so a whole lot of not-needed data, because the database browser /
manager can con display 1 picture from a selected record.
So I think, it would be more efficient to create 2 tables:
Persons
- Name
- Birthday
- ID ("this is a picture")
Blobs
- Name
- Picture
Now if I ask for the main table "Persons", I just get an ID (some
integer), that tells me that there is a picture.
The browser / manager can ask for just one record from the table Blobs,
to show me the picture of the selected line.
I've never seen such a construct in examples, so maybe I see ghosts
where there are none.
forgive me my ignorance.
cheers,
Stef Mientki
here is a C example http://www.sqlite.org/cvstrac/wiki?p=BlobExample
On 23/02/07, Stef Mientki <[EMAIL PROTECTED]> wrote:
hello,
I've started with SQLite, because it's one of the first dbases with a
local filessytem without authenciation.
It looks great, compared to ini-files.
Now I've a basic problem:
I've a table, with 10 simple fields and 1 blob field, containing a
(possibly large) image.
Uptill now the dbase is small so no performance problems yet.
But what if it grows ?
I want to look at the table in a table overview,
where the blob-field just displays the type of image
(identified by the fisrt 2 bytes SOI-code).
When I ask for the table through a query,
I get all the blob-filed information, while I only need the first 2
bytes,
and only the full picture of 1 selected record.
I can think of several solutions, but as my experience with databases is
almost zero, I can't decide
(and maybe I'm overlooking some better solutions)
solution 1:
add a extra field for each blob field, filled with the first 2 bytes of
a blob
solution 2:
put the blob fields in a separate table, with a link to the main table
any suggestions would be appreciated.
thanks,
Stef Mientki
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