sorting en calculating on internal relation

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sorting en calculating on internal relation

Postby martijn » Mon Jun 27, 2016 10:21 am

We have a table with cargo details
it is build up like this

CargoID | CargoByID | CargoAmount | CargoPackaging | CargoWeight

the CargoByID contains the ID of a the upper detail

An example of the database would be

1 | 1 | 2 | pallet | 10
2 | 1 | 10 | boxes | 0,1
3 | 2 | 200 | boy toys | 0,1
4 | 1 | 5 | boxes | 0,1
5 | 4 | 250 | girl toys| 0,2

i have to make a view which gives a correct list of the packing like
1 pallet 10 boxes 200 boy toys
5 boxes 250 girl toys
at this moment I just have build a string with the id's in it separated by "-" to sort the table an calculate from there.

for record 1 the string would be just 1
for record 3 the string would be 1-2-3

then I can use a for loop

But there must be a smarter way
martijn
 
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Joined: Mon Jun 27, 2016 10:06 am

Re: sorting en calculating on internal relation

Postby ROCLASI » Mon Jun 27, 2016 5:06 pm

Hi Martijn,

Essentially you are talking about hierarchical data, i.e. trees.

Take a look at my presentation from ServoyWorld 2008 on this subject. It was inspired by this blog post from PostgreSQL community member Hubert Lubaczewski (a.k.a. Depesz).
It explains how to use an adjacency list to query your tree with 1 single query (and also sort).

Hope this helps.
Robert Ivens
ROCLASI Software Solutions / JBS Group, Partner
SAN Developer / Servoy Valued Professional / Servoy Certified Developer
Twitter: @roclasi / @servoyforge
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Re: sorting en calculating on internal relation

Postby martijn » Tue Jun 28, 2016 10:30 am

Hi ROCLASI,

certainly seems to represent my problem. Thanks for the link
martijn
 
Posts: 18
Joined: Mon Jun 27, 2016 10:06 am


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