Using Databases with Python

仅供参考，还是自己做才能提升自己。

2. 

 

import sqlite3

conn = sqlite3.connect('emaildb.sqlite')
cur = conn.cursor()

cur.execute('DROP TABLE IF EXISTS Counts')

cur.execute('''
CREATE TABLE Counts (org TEXT, count INTEGER)''')

fname = input('Enter file name: ')
if (len(fname) < 1): fname = 'mbox.txt'
fh = open(fname)
for line in fh:
    if not line.startswith('From: '): continue
    pieces = line.split()
    email = pieces[1]
    org = email[(email.find('@')+1):]
    cur.execute('SELECT count FROM Counts WHERE org = ? ', (org,))
    row = cur.fetchone()
    if row is None:
        cur.execute('''INSERT INTO Counts (org, count)
                VALUES (?, 1)''', (org,))
    else:
        cur.execute('UPDATE Counts SET count = count + 1 WHERE org = ?',
                    (org,))

conn.commit()
# https://www.sqlite.org/lang_select.html
sqlstr = 'SELECT org, count FROM Counts ORDER BY count DESC LIMIT 10'

for row in cur.execute(sqlstr):
    print(str(row[0]), row[1])

cur.close()

 

3.

 

 

import xml.etree.ElementTree as ET
import sqlite3

conn = sqlite3.connect('trackdb.sqlite')
cur = conn.cursor()

# Make some fresh tables using executescript()
cur.executescript('''
DROP TABLE IF EXISTS Artist;
DROP TABLE IF EXISTS Genre;
DROP TABLE IF EXISTS Album;
DROP TABLE IF EXISTS Track;

CREATE TABLE Artist (
    id  INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT UNIQUE,
    name    TEXT UNIQUE
);

CREATE TABLE Genre (
    ID  INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT UNIQUE,
    name    TEXT UNIQUE
);

CREATE TABLE Album (
    id  INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT UNIQUE,
    artist_id  INTEGER,
    title   TEXT UNIQUE
);

CREATE TABLE Track (
    id  INTEGER NOT NULL PRIMARY KEY 
        AUTOINCREMENT UNIQUE,
    title TEXT  UNIQUE,
    album_id  INTEGER,
    genre_id  INTEGER,
    len INTEGER, rating INTEGER, count INTEGER
);
''')


fname = input('Enter file name: ')
if ( len(fname) < 1 ) : fname = 'Library.xml'

# Track ID369
# NameAnother One Bites The Dust
# ArtistQueen
def lookup(d, key):
    found = False
    for child in d:
        if found : return child.text
        if child.tag == 'key' and child.text == key :
            found = True
    return None

stuff = ET.parse(fname)
all = stuff.findall('dict/dict/dict')
print('Dict count:', len(all))
for entry in all:
    if ( lookup(entry, 'Track ID') is None ) : continue

    name = lookup(entry, 'Name')
    artist = lookup(entry, 'Artist')
    album = lookup(entry, 'Album')
    count = lookup(entry, 'Play Count')
    rating = lookup(entry, 'Rating')
    length = lookup(entry, 'Total Time')
    genree = lookup(entry, 'Genre')


    if name is None or artist is None or album is None or count is None or rating is None or length is None or genree is None:
        continue

    print(name, artist, album, count, rating, length, genree)

    cur.execute('''INSERT OR IGNORE INTO Artist (name) 
        VALUES ( ? )''', ( artist, ) )
    cur.execute('SELECT id FROM Artist WHERE name = ? ', (artist, ))
    artist_id = cur.fetchone()[0]

    cur.execute('''INSERT OR IGNORE INTO Genre (name) 
        VALUES ( ? )''', (genree,))
    cur.execute('SELECT ID FROM Genre WHERE name = ? ', (genree,))
    genre_id = cur.fetchone()[0]

    cur.execute('''INSERT OR IGNORE INTO Album (title, artist_id) 
        VALUES ( ?, ? )''', ( album, artist_id ) )
    cur.execute('SELECT id FROM Album WHERE title = ? ', (album, ))
    album_id = cur.fetchone()[0]

    cur.execute('''INSERT OR REPLACE INTO Track
        (title, album_id, genre_id, len, rating, count) 
        VALUES ( ?, ?, ?, ?,?,? )''',
        ( name, album_id, genre_id, length, rating, count ) )

    conn.commit()

 

4.

 

 

import json
import sqlite3
conn = sqlite3.connect('rosterdb.sqlite')
cur = conn.cursor()

cur.executescript('''
DROP TABLE IF EXISTS User; 
DROP TABLE IF EXISTS Member;
DROP TABLE IF EXISTS Course;

CREATE TABLE User(
    id   INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT UNIQUE,
    name TEXT UNIQUE 
);

CREATE TABLE Course(
    id   INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT UNIQUE,
    title TEXT UNIQUE 
);

CREATE TABLE Member(
    User_id INTEGER,
    Course_id INTEGER,
    role INTEGER,
    PRIMARY KEY(User_id,Course_id)
)
''')

fname = input('Enter file name: ')
if len(fname)< 1:
    fname = 'roster_data.json'

str_data = open(fname).read()
json_data = json.loads(str_data)

for entry in json_data:
    name = entry[0];
    title = entry[1];
    role = entry[2]
    print(name,title,role)

    cur.execute('''INSERT OR IGNORE INTO User (name)
        VALUES( ?)''',(name, ))
    cur.execute('SELECT id FROM User WHERE name = ?',(name, ))
    User_id = cur.fetchone()[0]

    cur.execute('''INSERT OR IGNORE INTO Course (title)
        VALUES (?)''',(title, ))
    cur.execute('SELECT id FROM Course WHERE title = ?',(title, ))
    Course_id = cur.fetchone()[0]

    cur.execute('''INSERT OR REPLACE INTO Member (User_id,Course_id,role)
        VALUES(?,?,?)''',(User_id,Course_id,role))
    
    conn.commit()

 

 

 

 

 

 

 

5.

geoload.py:

创建表格（地址，地理数据）

where.data存放大学名称；

for line in where.data:

    url + line.encode (并输出）

    读取数据data并decode

    输出包含字符个数

    count +1 

    js = json.loads(data)

    检查status是否存在并ok

    ok则address为大学名，地理数据为data （?为什么此时要encode）

200次结束