CODEWITHSUNDEEP
sqlbashsqlitebinary
kev
kev

Reputation: 161874

How to insert binary data into sqlite3 database in bash?

I want to insert binary data(png,jpg,gif,etc) into a sqlite3 database within a bash script.
I use the standalone binary sqlite3. How can I write the SQL statement?
Thanks for your help.

Upvotes: 7

Views: 15652

Answers (2)

user610650
user610650

Reputation:

Here is one way to do it. The file test.jpg is inserted in the table foo of the database foodb after being hexdumped to the binary literal format of sqlite:

[someone@somewhere tmp]$ sqlite3 foodb "create table foo (bar blob);"
[someone@somewhere tmp]$ echo "insert into foo values (X'`hexdump -ve '1/1 "%.2x"' test.jpg`');" | sqlite3 foodb

EDIT

And here we see that the data is store in "full-fidelity" as the .jpg file can be restored:

[somneone@somewhere tmp]$ sqlite3 foodb "select quote(bar) from foo;" | perl -ne 's/([0-9a-f]{2})/print chr hex $1/gie' > bla.jpg 
[somneone@somewhere tmp]$ ll *.jpg
-rw-rw-r-- 1 someone someone 618441 Apr 28 16:59 bla.jpg
-rw-rw-r-- 1 someone someone 618441 Apr 28 16:37 test.jpg
[someone@somewhere tmp]$ md5sum *.jpg 
3237a2b76050f2780c592455b3414813  bla.jpg
3237a2b76050f2780c592455b3414813  test.jpg

Furthermore, this approach is space efficient as it store the .jpg using sqlite's BLOB type. It doesn't stringify the image using for example base64 encoding.

[someone@somewhere tmp]$ ll foodb 
-rw-r--r-- 1 someone someone 622592 Apr 28 16:37 foodb

Upvotes: 5

David Souther
David Souther

Reputation: 8184

As I mentioned in the comment on @sixfeetsix's answer, inserting the data is only half the problem. Once it's in, you'll need to get it back out. We can use xxd for this.

#A nice hubble image to work with.
echo 'http://asd.gsfc.nasa.gov/archive/hubble/Hubble_20th.jpg' > imageurl.txt
image=imageurl.txt
curl $image > image.jpg

#Insert the image, using hexdump to read the data into SQLite's BLOB literal syntax.
echo "create table images (image blob);" | sqlite3 images.db
echo "insert into images (image) values(x'$(hexdump -ve '1/1 "%0.2X"' image.jpg)');" | sqlite3 images.db 2>&1

#Select just the one image, then use xxd to convert from hex back to binary.
echo "select quote(image) from images limit 1 offset 0;" | sqlite3 images.db  | tr -d "X'" | xxd -r -p > newimage.jpg
eog newimage.jpg

Upvotes: 10

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