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updated documentation

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yorek
2017-12-22 10:02:37 -08:00
parent cba3faa417
commit b0b6e74501
2 changed files with 14 additions and 14 deletions
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samples/features/sql-clr/TransitiveClosure/README.md
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@@ -1,5 +1,9 @@
# Implementing Transitive Closure Clustering in SQL Server using CLR UDF
SQL Database don't have built-in support for transitive closure clustering, so the only workaround is to implement this algorithm in .Net framework and expose it as T-SQL function.
A discussion on the problem, the algorithm and a pure T-SQL based solution can be found here:
- [Transitive Closure Clustering with SQL Server, UDA and JSON](https://medium.com/@mauridb/transitive-closure-clustering-with-sql-server-uda-and-json-dade18953fd2)
- [T-SQL Puzzle Challenge Grouping Connected Items](http://www.itprotoday.com/microsoft-sql-server/t-sql-puzzle-challenge-grouping-connected-items)
This code sample demonstrates how to create CLR User-Defined aggregate that implements clustering.
### Contents
@@ -17,7 +21,7 @@ This code sample demonstrates how to create CLR User-Defined aggregate that impl
2. **Key features:**
- CLR, JSON
3. **Programming Language:** .NET C#
4. **Author:** Davide Mauri, Jovan Popovic [jovanpop-msft]
4. **Author:** [Davide Mauri](https://github.com/yorek), Jovan Popovic [jovanpop-msft]
<a name=build-functions></a>
@@ -65,8 +69,9 @@ Once you create the assembly and expose the aggregate, you can use it to cluster
declare @edges table(n1 int, n2 int);
insert into @edges
values (1,2),(2,3),(3,4),(4,5),(2,21),(2,22),
              (7,8),(8,9),(9,10);
values
(1,2),(2,3),(3,4),(4,5),(2,21),(2,22),
(7,8),(8,9),(9,10);
select TC.CLUSTERING(n1,n2)
from @edges;
@@ -74,21 +79,21 @@ from @edges;
The result will be JSON document that groups the numbers that belong to the same cluster.
```javascript
{
"0":[1,2,3,4,5,21,22],
"1":[7,8,9,10]
"0":[1,2,3,4,5,21,22],
"1":[7,8,9,10]
}
```
You can transform this JSON document into relational formatusing **OPENJSON** function:
```
select cluster = [key], elements = value
from openjson(
       (select TC.CLUSTERING(n1,n2) from @edges)
(select TC.CLUSTERING(n1,n2) from @edges)
);
```
The result of this query is:
|cluster|elements|
|----|---|
|---|---|
|0|[1,2,3,4,5,21,22]|
|1|[7,8,9,10]|
samples/features/sql-clr/TransitiveClosure/TransitiveClosureAggregate.cs
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@@ -14,11 +14,9 @@ namespace TransitiveClosure
public class Group: IEnumerable<int>
{
private int? _groupRoot = null;
private Dictionary<int, bool> _group = new Dictionary<int, bool>();
public Dictionary<int, bool>.KeyCollection Elements => _group.Keys;
public int Count => _group.Keys.Count;
public bool ContainsElement(int element)
@@ -89,13 +87,12 @@ namespace TransitiveClosure
public class GroupSet: IEnumerable<Group>
{
private List<Group> _groupSet = new List<Group>();
// This keeps about the distinct numbers and in which group they are
private Dictionary<int, Group> _numbers = new Dictionary<int, Group>();
private int _merges = 0;
public int Groups => _groupSet.Count;
public int Numbers => _numbers.Count;
public int Merges => _merges;
public void Add(Group group)
@@ -212,9 +209,7 @@ namespace TransitiveClosure
private GroupSet _groupSet;
public int Groups => _groupSet.Groups;
public int Numbers => _groupSet.Numbers;
public int Merges => _groupSet.Merges;
public void Init()