use case for uuid in database - sql

Question

Let's say for example I have a table called test and the data is like that:
id name
1 John
2 Jay
3 Maria
Let's suppose this test gets updated and now the ids the names are for some reason allocated to different id , consider the name column as a unique column, it's just not the pprimary key of test but unique.
Next time I query test it may look like that:
id name
10 John
12 Jay
13 Maria
So in that case the id changed but the name is consistent can be traced back to the previous state of the test table. I believe this is bad practice to change id like that, but I don't have control over this table and this is how some folks handle right now the data. I would like to know if this is a good case for using uuid ? I'm not familiar with the concept of uuid, and how it's best to create something consistent as uniquely identifiable and also fast on search when I want to handle the data changes in this table. I would like to import this table on my end but create a key that is fast and that will not change during data imports.

Answer 1

I feel like the problem you're trying to solve isn't clear.
Problem 1: The id column keeps getting updated. This seems weird so getting to the root of why that is happening seems like the real issue to resolve.
Problem 2: Uniquely identifying rows. You would like to use the id column or a new uuid column to uniquely identify but you've already said you can uniquely identify rows with the name column so what problem are you trying to solve here.
Problem 3: Performance. You're going to get best performance using an indexed integer (preferably primary key) column. Most likely id in this case. uuid won't help with performance.
Problem 4: Data changing on imports. This is likely due to auto increments or initial values set differently in DDL. You need to get a better understanding of what exactly is going wrong with your import.
Problem 5: If you don't have control over the values of the id column how would you be able to add your own uuid?
uuid is just a way of creating a unique value.
Oracle has a function to create uuid random_uuid().

Answer 2

This is an XY-problem.
You have data in your table with a unique key in a given data type and when it gets reloaded then the unique key is being regenerated so that all the data gets given new unique values.
The data type you use does not matter; the issue is with the process of reloading the data and regenerating the unique keys. If you use a different data type and the unique keys are still regenerated then you have exactly the same problem.
Fix that problem first.

Answer 3

Putting aside the reasons for this question and does it make sense or not. If I got it right it is about generation of a unique key from NAME which is unique itself.
If that is the case then you could create your on function to do the job:
CREATE OR REPLACE FUNCTION NAME_2_ID(p_name VARCHAR2) RETURN NUMBER AS
BEGIN
--
Declare
mRet Number(16);
mAlpha VarChar2(64);
mWrk Number(16) := 0;
mANum VarChar2(4000) := '';
--
Begin
IF p_name Is Null Then
mRet := 0;
GOTO End_It;
END IF;
--
mAlpha := ' ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789'',.!?"()[]{}';
-- ---------------- Replacing Alpha To Numeric -----------------------------------------------------------------------------------------------
For i In 1 .. Length(p_name) Loop
mANum := mANum || SubStr(p_name, i, 1) || To_Char(InStr(mAlpha, Upper(SubStr(p_name, i, 1)))) || '~';
mWrk := mWrk + InStr(mAlpha, Upper(SubStr(p_name, i, 1)));
End Loop;
mRet := mWrk * Length(mANum);
<<End_It>>
RETURN(mRet);
End;
END NAME_2_ID;
As your ID column in TEST table is changing like in sample data:
WITH
test_1 AS
(
Select 1 "ID", 'John' "A_NAME" From Dual Union All
Select 2 "ID", 'Jay' "A_NAME" From Dual Union All
Select 3 "ID", 'Maria' "A_NAME" From Dual
),
test_2 AS
(
Select 10 "ID", 'John' "A_NAME" From Dual Union All
Select 12 "ID", 'Jay' "A_NAME" From Dual Union All
Select 13 "ID", 'Maria' "A_NAME" From Dual
)
... you can get the same ID_2 whenever you query the table (if name didn't
change) ...
Select
ID,
A_NAME,
NAME_2_ID(A_NAME) "ID_2"
From
test_1
/*
ID A_NAME ID_2
---------- ------ ----------
1 John 765
2 Jay 429
3 Maria 846
*/
-- -------------------------
... ... ...
From
test_2
/*
ID A_NAME ID_2
---------- ------ ----------
10 John 765
12 Jay 429
13 Maria 846
*/