保存时如何在 Python 中保持 SQL 列的顺序？

Question

If you scroll down a bit you can see this code from gddc return SQL table as JSON in python :

qry = "Select Id, Name, Artist, Album From MP3s Order By Name, Artist"
# Assumes conn is a database connection.
cursor = conn.cursor()
cursor.execute(qry)
rows = [x for x in cursor]
cols = [x[0] for x in cursor.description]
songs = []
for row in rows:
  song = {}
  for prop, val in zip(cols, row):
    song[prop] = val
  songs.append(song)
# Create a string representation of your array of songs.
songsJSON = json.dumps(songs)

I just want to keep the order of my columns.

For example when I print(cols) I get this:

['id', 'Color', 'YCoord', 'Width', 'Height'] # right order

But the columns are saved in a wrong order:

[{"Color": "#FF99FF","Width"=345, "id"=43, "YCoord"=5784 "Height"=-546}...] # wrong order

The more columns I add, the more random it gets.

Answer 1

Python dict不保存键的顺序，而是使用OrderedDict 。

Answer 2

If I understand You want dictionary to have ordered key. It's not possible, because dictionaries are not keeping keys in some order, because keys are used only to access elements. You can always print columns of data using raw column information:

cols = ["column1", "column2", "column3"]
for row in data_from_database:
    for col in cols:
        print row[col]