Changes between Version 13 and Version 14 of CompositePrimaryKeyDesignNotes


Ignore:
Timestamp:
09/01/2012 11:28:10 PM (3 years ago)
Author:
bignose
Comment:

discuss using a set for the primary key

Legend:

Unmodified
Added
Removed
Modified
  • CompositePrimaryKeyDesignNotes

    v13 v14  
    44
    55== Design Questions ==
    6 ''How do you define multiple primary keys?''
    76
    8 The "neatest" solution would be to allow primary_key=True on multiple fields but this may be precluded by other design considerations.
     7* ''How do you define multiple primary keys?''
    98
    10 ''How do you foreign key onto a table with a composite foreign key?''
     9  The "neatest" solution would be to allow primary_key=True on multiple fields but this may be precluded by other design considerations.
    1110
    12 ''What do you use for .get(pk=foo) with a composite primary key?''
     11* ''How do you foreign key onto a table with a composite foreign key?''
    1312
    14 The likely solution is to use a tuple or dictionary though there is mention of the comment framework overlapping with this.
     13  The primary key is a set of the columns.
    1514
    16 ''How does Admin map a url to an object?''
     15* ''What do you use for .get(pk=foo) with a composite primary key?''
    1716
    18 Should be able to be handled with some nice url escaping.
     17  The primary key is a set of the columns.
     18
     19  The likely solution is to use a set, though there is mention of the comment framework overlapping with this.
     20
     21* ''How does Admin map a url to an object?''
     22
     23  Possible solutions (for a key with the value {{{ { val_foo, val_bar, val_baz } }}}:
     24
     25  * {{{/appname/modulename/val_foo,val_bar,val_baz/}}}
     26
     27    How to deal with values containing commas? Should be able to be handled with some nice url escaping.
     28
     29  * {{{/appname/modulename/val_foo/val_bar/val_baz/}}}
     30
     31* ''The columns of a key are a set, and have no implicit order. How to deal with identity between different orders of the same set?''
    1932
    2033== Affected Areas ==
    2134
    2235=== Models ===
     36
    2337[wiki:CompositePrimaryKeyModelNotes On going in depth notes]
    2438
     
    3246
    3347=== Queries ===
     48
    3449Model.objects.get(pk=foo) needs to be supported.
     50
     51Solution: the primary key is a set of the column values.
    3552
    3653=== Forms ===
    3754
    3855=== Admin ===
     56
    3957Expect there is a large amount of work in here making sure all the model inspection and form generation works.
    4058
     
    4260
    4361=== Serialization ===
     62
    4463Code needs to be looked at further but all the foreign keying is likely to need attention.
    4564
    4665== Relevant Discussions ==
     66
    4767* Jul 2008 http://groups.google.com/group/django-developers/browse_thread/thread/4b2370a0652d9135/2344ca721a4213fd (David Cramer initial thoughts)
    4868
Back to Top