One Bowler can not bowl two consecutive over in cricket - sql-server

Question

I am working on Cricket Project. I have a table OverDetails. I want to insert data in this table.
ID OverNumber BowlerID InningsID
1 1 150 1
2 4 160 1
3 3 165 1
4 2 150 1
Row_1, Row_2 and Row_3 are legal. Row_4 is not legal, because one bowler can not through two consecutive overs in one innings. It is not necessary that overs are added consecutively in database.
I have added a constraint in SQL Server.
#Constraint_1
ALTER TABLE OverDetails ADD CONSTRAINT UniqueOverInInning
UNIQUE(OverNumber, BowlerID, IninngsID);
This constraint works perfectly.
I need a check like this:
#Constraint_2
ALTER TABLE OverDetails ADD CONSTRAINT UniqueConsecutiveBowlerInOneInning
CHECK (OverNumber + 1 != OverNumber and BowlerID + 1 != BowlerID
and IninngID + 1 != IninngID)

Answer 1

You need a function which returns a last BowlerID from a given InningID:
CREATE FUNCTION dbo.GetBowlerID
( #InningId INT, #OverNumber INT, #BowlerID INT)
RETURNS INT
AS
BEGIN
RETURN (SELECT top 1 CASE WHEN
(SELECT BowlerID
FROM OverDetails
WHERE InningsId = #InningId AND OverNumber = #OverNumber - 1 ) = #BowlerID
OR
(SELECT BowlerID
FROM OverDetails
WHERE InningsId = #InningId AND OverNumber = #OverNumber + 1 ) = #BowlerID
THEN 1 else 0 end)
END
Then you can put it into a check constraint:
ALTER TABLE OverDetails ADD CONSTRAINT UniqueConsecutiveBowlerInOneInning
CHECK (dbo.GetBowlerID(InningsId, OverNumber, BowlerID)=0)

Answer 2

Check constraints cannot directly reference other rows data. There are some techniques that try to use UDFs to get around this limitation but they tend to not work well. Especially in this case where I presume the insert of row 4 should also be blocked if it had a bowlerID of 165 since that would mean overs 2&3 shared a bowler.
Instead, we can implement this with a pair of views. I usually put DRI somewhere in the name of views like this to indicate that they're there for Declarative Referential Integrity reasons, not because I intend people to query them.
create table dbo.Bowling (
ID int not null,
OverNumber int not null,
BowlerID int not null,
InningsID int not null,
constraint PK_Bowling PRIMARY KEY (ID),
constraint UQ_Bowling_Overs UNIQUE (OverNumber,InningsID)
)
go
create view dbo.Bowling_DRI_SuccessiveOvers_Odd
with schemabinding
as
select
(OverNumber/2) as OddON,
BowlerID
from
dbo.Bowling
go
create unique clustered index UQ_Bowling_DRI_SuccessiveOvers_Odd on dbo.Bowling_DRI_SuccessiveOvers_Odd (OddON,BowlerID)
go
create view dbo.Bowling_DRI_SuccessiveOvers_Even
with schemabinding
as
select
((OverNumber+1)/2) as EvenON,
BowlerID
from
dbo.Bowling
go
create unique clustered index UQ_Bowling_DRI_SuccessiveOvers_Even on dbo.Bowling_DRI_SuccessiveOvers_Even (EvenON,BowlerID)
go
insert into dbo.Bowling(ID,OverNumber,BowlerID,InningsID) values
(1,1,150,1),
(2,4,160,1),
(3,3,165,1)
go
insert into dbo.Bowling(ID,OverNumber,BowlerID,InningsID) values
(4,2,150,1)
This final insert generates the error:
Msg 2601, Level 14, State 1, Line 37 Cannot insert duplicate key row
in object 'dbo.Bowling_DRI_SuccessiveOvers_Even' with unique index
'UQ_Bowling_DRI_SuccessiveOvers_Even'. The duplicate key value is (1,
150). The statement has been terminated.
Hopefully, you can see the trick I'm employing to make these views check your desired constraint - it's set up so that rows are paired with either their (logical, based on OrderNumber) successor or predecessor based on dividing the OrderNumber by two using integer maths.
We then apply unique constraints on these pairs and including the BowlerID. Only if the same bowler bowls two successive overs will we generate more than one row with the same (OddON/EvenON) and BowlerID values.

Answer 3

Maybe this one?
create function dbo.chk_fnk (#OverNumber int, #BowlerID int, #InningsID int)
returns int
as
begin
return
case when
exists (select *
from dbo.OverDetails
where BowlerID = #BowlerID and abs(OverNumber - #OverNumber) = 1 and InningsID = #InningsID)
then 1
else 0
end;
end;
go
ALTER TABLE dbo.OverDetails ADD CONSTRAINT UniqueConsecutiveBowlerInOneInning
CHECK (dbo.chk_fnk(OverNumber, BowlerID, InningsID) = 0);