CODEWITHSUNDEEP
sqllinqlinq-to-sql
callisto
callisto

Reputation: 5083

Creating a two-level hierarchy in LINQ

I have two tables in SQL:

DOCUMENT
ID int
Description varchar(50)

DOCUMENTLINK
ParentID int
ChildID int

How do I return the hierarchy (only two levels are used) formed by these two tables as an object using LINQ?

The structure would be something like:

Parent1  
---------Child1  
---------Child2  
Parent2  
---------Child3  
Parent3  
Parent4  
---------Child2  
---------Child3  
Parent5  
---------Child1  
---------Child4
---------Child5

Upvotes: 0

Views: 104

Answers (2)

Denise Skidmore
Denise Skidmore

Reputation: 2416

LINQ answer:

var tree = from top in nodes
           from middle in nodes
           from bottom in nodes
           where top.Id == middle.ParentId
           && middle.Id == bottom.Id
           select new
           {
               Top = top,
               Middle = middle,
               Bottom = bottom
           };

Upvotes: 2

Denise Skidmore
Denise Skidmore

Reputation: 2416

The SQL answer is:

SELECT *
FROM (Table1
INNER JOIN Table1 AS Table1_1 ON Table1.ParentID = Table1_1.ID)
INNER JOIN Table1 AS Table1_2 ON Table1_1.ParentID = Table1_2.ID;

Note, this will only show items that have all levels. To get childless parents included, change all the inner joins to left outer joins

Upvotes: 1

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