ΘΕΜΑ: εισαγωγή εικόνας από βάση δεδομένων

Reading images
 
In the previous example, we have inserted an image into the database table. Now we are going to read the image back from the table.
 
#!/usr/bin/python
# -*- coding: utf-8 -*-
 
import MySQLdb as mdb 
 
def writeImage(data):
 
    fout = open('woman2.jpg', 'wb')
 
    with fout:
 
        fout.write(data)
 
con = mdb.connect('localhost', 'testuser', 'test623', 'testdb')
 
with con:
 
    cur = con.cursor()
 
    cur.execute("SELECT Data FROM Images WHERE Id=1")
    data = cur.fetchone()[0]
    writeImage(data)    
 
We read one image from the Images table.
 
cur.execute("SELECT Data FROM Images WHERE Id=1")
 
We select one record from the table.
 
fout = open('woman2.jpg', 'wb')
 
We open a writable binary file.
 
fout.write(data)
 
We write the data to the disk.
 
Now we should have an image called woman2.jpg in our current directory. We can check if it is the same image that we have inserted into the table. 

import sqlite3
import os
 
 
def create_or_open_db(db_file):
    db_is_new = not os.path.exists(db_file)
    conn = sqlite3.connect(db_file)
    if db_is_new:
        print('Creating schema')
        sql = "CREATE TABLE imagestest (id INTEGER PRIMARY KEY, \
        imgcontent BLOB, \
        name TEXT);"
        conn.execute(sql) # shortcut for conn.cursor().execute(sql)
    else:
        print('Schema exists\n')
    return conn
 
 
def insert_picture(conn, picture_file):
    with open(picture_file, 'rb') as input_file:
        ablob = input_file.read()
        base = os.path.basename(picture_file)
 
        sql = "INSERT INTO imagestest(imgcontent, name) VALUES(?, ?)"
        conn.execute(sql,[sqlite3.Binary(ablob), base]) 
        conn.commit()
 
 
def extract_picture(cursor):
    sql = "SELECT imgcontent, name from imagestest"
    cursor.execute(sql)
    ablob, filename = cursor.fetchone()
    with open(filename, 'wb') as output_file:
        output_file.write(ablob)
    return filename
 
if __name__ == '__main__':
    conn = sqlite3.connect("images.db")
    cur = conn.cursor()
    extract_picture(cur)

import sqlite3
 
conn = sqlite3.connect("images.db")
cur = conn.cursor()
qry = "CREATE TABLE imagestest (id INTEGER PRIMARY KEY, \
        imgcontent BLOB, \
        name TEXT);"
cur.execute(qry)
conn.commit()
 
img = sqlite3.Binary(open('portrait.jpg', 'rb').read())
nm = 'portrait.jpg'
 
qry1 = "INSERT INTO imagestest(imgcontent, name) VALUES(?, ?)"
cur.execute(qry1, (img, nm))
conn.commit()
cur.close()
conn.close()