音乐曲目数据库

Question

因此，我试图通过使用SQLite来打开我正在创建的数据库，从而获得这个帖子底部的表。zip文件包含我试图修改的代码，还包括itunes库，我从itunes库中获取了SQLite中表的值。我不知道如何在我的表中添加一个类型字段，也不知道如何提取最后三个标题，您可以在本页的底部看到。任何帮助都将不胜感激。

这是我作业的提示：

音乐曲目数据库

此应用程序将以XML读取iTunes导出文件，并生成具有此结构的适当规范化数据库：

要对此分配进行分级，该程序将在上载的数据库上运行这样的查询，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

如果一切都做对了，我应该得到这样的结果：

最终输出表

下面是我的代码，在这里，我很难更改代码的类型部分。我应该在SQLite中得到一个体裁表。此外，我需要得到相同的结果，我在我的表上。

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

以下是适用于您的情况的完整代码：

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 2

我认为你只需要调整你的继续声明，以包括类型。我调整了您发布的代码，并使用Python2.7和SQLite运行它，它输出的数据库没有任何错误。

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

我要注意的是，要获得上面显示的输出，您需要将SELECT语句更改为逐轨顺序以及艺术家顺序。

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 3

我不能百分之百肯定我是否理解你的问题，但我想说的是：

看起来，您所需要做的就是读取XML文件，并将其放入表中。这是我如何处理类型-我会保留一个已经看到的类型列表，每次新的类型出现，我会把它添加到类型表。由于数据库设置中没有使用外键，因此在插入歌曲行时，需要再次从表中获取类型ID以供使用。

你也会为专辑做同样的事情。