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c#linqentity-framework
Jorge
Jorge

Reputation: 18257

implementing a recursive linq

So let's say that I have a table with a relation with itself, for example

Table Page
-------------
IDPage 
description    
IDPage_FK <-- foreign key

Now this table it's mapped by entity framework like this

Class Page
-----------
int IDPage
string description
int IDPage_FK
Page Page1
IColletion<Page> Page2

What I want to archive if it's possible, it's created a linq expression to navigate on all the table an make an output like this in a string variable:

Assuming this values in the table

IDPage    Description    IDPage_FK

1         Example        null

2         Example2         1

3         Example3         2

This output on a string variable

string inheritance = (from P in Page Select....)

The output will be like this

Example > Example2 > Example3

It's possible? or Do I have to create a method to loop into each element an create the variable?

Upvotes: 1

Views: 299

Answers (3)

Amy B
Amy B

Reputation: 110221

If you add a root node property into your model, you can query two levels: root nodes, all their children by root node id. Then you can recurse against the in-memory instances to produce your string.

Upvotes: 0

FMM
FMM

Reputation: 4329

Have you considered the nested set model rather than the parent pointer for mapping hierarchical relationships in a database table?

(Granted this isn't an answer, but may guide you down a better road long term)

Upvotes: 1

eouw0o83hf
eouw0o83hf

Reputation: 9598

Sorry, you can't do recursive Linq out to a database - you'll probably either have to write an iterative function or create a stored procedure to do it for you.

Similar question:

How does Entity Framework work with recursive hierarchies? Include() seems not to work with it

Upvotes: 1

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