How to fit multiple equal references into table structure? - sql

How to fit multiple equal references into table structure? How could I do that? For example: I have list of classmates:
1 Peter
2 Jack
3 John
4 Mary
5 Birgit
6 Stella
7 Janus
8 Margo
9 Fred
Now I want to define fellowships. In first place, let's limit that every kid may belong to one fellowship. So we could have 3 fellowships:
[Peter, Jack]
[John, Mary, Birgit]
[Stella, Janus, Margo, Fred]
All members are equal, so they all should reference to other members. Is there better ways to define such relations than just to have table of pairs? Like:
1 2
3 4
3 5
4 5
4 3
5 3
5 4
6 7
6 8
6 9
7 6
7 8
7 9
8 6
8 7
8 9
9 6
9 7
9 8
If using table of pairs, is it better to describe relation both way (like above), or is it enough to have link just from one way to another? What are the benefits of both ways?
Table of pairs does not constrain any member into just one fellowsip, but how would it possible?
I was looking for SQL table solution, but maybe there are better tools for handling such data-structures, so I added nosql-tag too. I am looking for right tools for such data, but I am eager to know, how to fit it in SQL tables too.

Yes, there is another way. If you have "fellowships", then you do not have pair-wise relationships. STart with a Fellowships table that has a FellowshipsId.
Then you would have a FellowshipsKids table. This is called a junction table, and it would have one row for each member of each fellowship. It would have rows like this:
FellowshipId KidId
1 1
1 2
2 3
2 4
2 5
. . .
What you have is an m-n relationship between fellowships and kids -- one fellowship can have multiple kids, one kids can be in multiple fellowships. A junction table is the standard way of represent this in a relational database.

Related

How to find related issues in a hierarchy

I have a table that contains parent child relationships and I need to find all related issues.
Parent
Child
1
3
1
4
2
4
5
6
7
6
I need to be able to identify all related issues, ideally I could return a new table that returns the following.
Issue
Group
1
1
2
1
3
1
4
1
5
2
6
2
7
2
I'm currently using CTEs to try and solve this, but I'm running into circular reference issues and I'm not sure how to create a group number for each. Essentially, it is just tracing up and down different parents and each group does not have one central parent node which I think may be causing the issues.

Reduce two columns of IDs with a many to many relationship

I have a dataset with two columns of non-unique IDs (ID-A and ID-B respectively).
A single ID-A can have multiple ID-Bs and vice versa. I am trying to generate a third, set identifier using transitivity (calling it ID-C) which is set to the same value for all records with either ID-A or ID-B in common. Two records having neither ID-A nor ID-B in common should only share an ID-C set identifier if there is a transitive chain of records between them.
To visualize, I have something like the first two columns, and want to generate the third column(ID-C)
ID-A ID-B ID-C
1 1 1
1 2 1
1 3 1
2 2 1
2 4 1
3 4 1
4 5 2
5 5 2
5 6 2
6 7 3
I am using Presto SQL inside of AWS Athena, so I cannot use any variables or loops, that I am aware of.

SQL table structure for store value against list of combination

I have a requirement from client where I need to store a value against list of combination.
For example I have following LOBs and against each combination I need to store a value.
Auto
WC
Personal
I purposed multiple solutions he is not satisfied with anyone.
Solution 1: create single table, insert value against all possible combination(string) something like
LOB Value
Auto 1
WC 2
Personal 3
Auto,WC 4
Auto, personal 5
WC, Personal 6
Auto, WC, Personal 7
Solution 2: create lkp_lob, lob_group and lob_group_detail tables. Each group combination represent a group.
Lkp_lob
Lob_key Name
1 Auto
2 WC
3 Person
Lob_group (unique query constrain on lob_group_key and lob_key)
Lob_group_key Lob_key
1 1
2 2
3 3
4 1
4 2
5 1
5 3
6 2
6 3
7 1
7 2
7 3
Lob_group_detail
Lob_group_key Value
1 1
2 2
3 3
4 4
5 5
6 6
7 7
Any suggestion would be highly appreciated.
First of all I did not understood that terms you said.
But from database perspective it is always good to have multiple tables for each module. You will be facing less difficulties when doing CRUD. And will be more faster.

Count instances of number in Row

I have a sheet formated somewhat like this
Thing 5 6 7 Person 1 Person 2 Person 3
Thing 1 1 2 7 7 6
Thing 2 5 5
Thing 3 7 6 6
Thing 4 6 6 5
I am trying to find a query formula that I can place in the columns labeled 5,6,7 that will count the number of people who have that amount of Thing 1. For example, I filled out the Thing 1 row, showing that 1 person has 6 of Thing 1 and 2 people have 7 of Thing 1.
You can use this function: "COUNTIF".
The formula to write in the cells will look like this:
=COUNTIF(E2:G2;"=5")
For more information regarding this function, check the documentation: https://support.google.com/docs/answer/3093480?hl=en

In MSSQL filter rows based on an ID exists in a column as comma separated string

I've Benchmarking table like this
BMID TestID BMTitle ConnectedTestID
---------------------------------------------------
1 5 My BM1 0
2 6 My BM2 5
3 7 My BM3 5,6
4 8 My BM4 10,12,8
5 9 My BM5 0
6 10 My BM6 3,6
7 5 My BM7 8,3,12,9
8 3 My BM8 7,10
9 8 My BM9 0
10 12 My BM10 9
---------------------------------------------
Explaining the table a little
Here the TestID and the connected TestID is playing the roles. If the user wants all the benchmarks for the TestID 3
It should return rows where testID=3 and also if any rows having connectedTestID column having that testID in it among the comma separated values
That means if the user specify the value 3 as the testID, it should return
---------------------------------------------
8 3 My BM8 7,10
7 5 My BM7 8,3,12,9
6 10 My BM6 3,6
--------------------------------------------
Hope its clear how those 3 rows returned. Means First row is because the testID 3 is there. the other two rows because 3 is in their connectedIDs cell
You should fix the data structure. Storing numeric ids in a comma-delimited list is a bad, bad, bad idea:
SQL Server doesn't have the best string manipulation functions.
Storing numberings as character strings is a bad idea.
Having undeclared foreign key relationships is a bad idea.
The resulting queries cannot make use of indexes.
While you are exploring what a junction table is so you can fix the problem with the data structure, you can use a query such as this:
where testid = 3 or
',' + ConnectedTestID + ',' like '%,3,%'