Question

所以我试图通过使用SQLite打开我正在创建的数据库来获取本文底部的表格。 zip文件包含我试图修改的代码，还包括itunes库，我从中获取SQLite中表的值。我不知道如何在我的表格中添加一个类型字段，也不知道如何提取你可以在本页底部看到的最后三个标题。任何帮助将不胜感激。

所以这是我的家庭作业的提示：

音乐曲目数据库

此应用程序将以XML格式读取iTunes导出文件，并使用以下结构生成正确规范化的数据库：

要对此作业进行评分，程序将在您上传的数据库中运行这样的查询并查找它希望看到的数据：

SELECT Track.title, Artist.name, Album.title, Genre.name 
    FROM Track JOIN Genre JOIN Album JOIN Artist 
    ON Track.genre_id = Genre.ID and Track.album_id = Album.id 
        AND Album.artist_id = Artist.id
    ORDER BY Artist.name LIMIT 3

如果一切正确完成，我应该得到的结果是：

Final output Table

这是我的代码，我无法更改代码的类型部分。我应该在SQLite中获得一个流派表。另外，我需要得到与上面表格中相同的结果。

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 Album;
DROP TABLE IF EXISTS Track;
DROP TABLE IF EXISTS Genre;

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

# <key>Track ID</key><integer>369</integer>
# <key>Name</key><string>Another One Bites The Dust</string>
# <key>Artist</key><string>Queen</string>
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')
    genre = lookup(entry, 'Genre')

    if name is None or artist is None or album is None :
        continue

    print name, artist, album, genre, count, rating, length

    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 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 IGNORE INTO Genre (name)
        VALUES ( ? )''', ( genre, ) )
    cur.execute('SELECT id FROM Genre WHERE name = ? ', (genre, ))
    genre_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()

Answer 1

我认为你必须调整你的继续声明以包括流派。我调整了您发布的代码，并使用Python 2.7和SQLite运行它，并输出一个没有错误的数据库。

if name is None or artist is None or genre is None or album is None :
    continue

我要注意，要获得上面显示的输出，您需要将SELECT语句更改为按轨道和艺术家排序。

SELECT Track.title, Artist.name, Album.title, Genre.name 
FROM Track JOIN Genre JOIN Album JOIN Artist 
ON Track.genre_id = Genre.ID and Track.album_id = Album.id 
    AND Album.artist_id = Artist.id
ORDER BY Artist.name, track.title LIMIT 3

Answer 2

以下是适合您情况的完整代码：

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 Album;
DROP TABLE IF EXISTS Genre;
DROP TABLE IF EXISTS Track;

CREATE TABLE Artist (
    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 Genre (
    id  INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT UNIQUE,
    name   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 = raw_input('Enter file name: ')
if ( len(fname) < 1 ) : fname = 'Library.xml'

# <key>Track ID</key><integer>369</integer>
# <key>Name</key><string>Another One Bites The Dust</string>
# <key>Artist</key><string>Queen</string>
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')
    genre = lookup(entry, 'Genre')
    count = lookup(entry, 'Play Count')
    rating = lookup(entry, 'Rating')
    length = lookup(entry, 'Total Time')

    if name is None or artist is None or genre is None or album is None: 
        continue

    print name, artist, album, genre, count, rating, length

    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 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 IGNORE INTO Genre (name) 
    VALUES ( ? )''', ( genre, ) )
    cur.execute('SELECT id FROM Genre WHERE name = ? ', (genre, ))
    genre_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()

Answer 3

如果我理解你的问题，我不是百分百肯定，但这是一个镜头：

看起来您需要做的就是在XML文件中读取，并将其放入表中。以下是我将如何处理这种类型 - 我会保留已经看过的类型列表，每次出现新类型时，我都会将其添加到流派表中。由于您没有在数据库设置中使用外键，因此您需要再次从表中获取类型ID以在插入歌曲行时使用。

你也会为专辑做同样的事情。

Answer 4

通过添加流派来修改数据库。只需按照基本示例添加流派即可这是使用python 3的代码

import xml.etree.ElementTree as ET
import sqlite3
#connects to database, creates a sqlite file
conn = sqlite3.connect('trackdb1.sqlite')
cur  = conn.cursor()

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

CREATE TABLE Artist (
    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
);


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

''')


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

# <key>Track ID</key><integer>369</integer>
# <key>Name</key><string>Another One Bites The Dust</string>
# <key>Artist</key><string>Queen</string>
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

#create element tree and find the branch
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')
    genre_name = lookup(entry, 'Genre')

    if name is None or artist is None or album is None or genre_name is None:
        continue

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

    #insert data into table
    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 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 IGNORE
    INTO Genre(name)
        VALUES (?)''', (genre_name, ))
    cur.execute('SELECT ID FROM Genre WHERE name = ?', (genre_name, ))
    genre_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()

音乐曲目数据库

4 个答案: