Optimize stored procedure query - firebird

Question

I have 2 tables in a Firebird 2.5 db:
SL_SPORS
-----------------
ID_PERS ID_SUMSP
10 2
10 3
11 2
SL_BRUTS
----------------------------------------
ID_PERS S_SPORS_1 S_SPORS_2 S_SPORS_3 ...
10 0 50 0
11 0 0 0
I need to get ID_PERS and ID_SUMSP from first table where S_SPORS_[ID_SUMSP] is 0 in second table,ID_SUMSP is from 1 to 7,in SL_BRUTS there is only one record for a person
I have a stored procedure:
CREATE OR ALTER PROCEDURE SP_VALIDSUM()
RETURNS (RES VARCHAR(500)) AS
....
FOR SELECT A.ID_PERS,S.ID_SUMSP FROM SL_SPORS INTO :ID_PERS,:ID_SUMSP DO
BEGIN
SUMA=0;
EXECUTE STATEMENT 'SELECT FIRST 1 S_SPORS_'||:ID_SUMSP||' FROM SL_BRUTS WHERE ID_PERS='||:ID_PERS INTO :SUMA;
IF (SUMA=0) THEN
BEGIN
RES='SUM 0 FOR ID_PERS='||:ID_PERS||' AND ID_SUMSP='||:ID_SUMSP;"
SUSPEND;
END
END
it is working but I want to know if there is a better solution,for example maybe I can load all ID_SUMSP from first table in single query using LIST(..)..or I can check all 1-7 fields from table 2 on a single query

Answer 1

You have to change the structure (Schema) of the second table - read Martin Gruber's "Essential SQL" or any other tutorial on "database normalization". SL_BRUTS table should be re-molded to have three columns: ID_PERS and ID_SUMSP and S_SPORS
https://en.wikipedia.org/wiki/Database_normalization
Do one-time data conversion and then do your queries over normalized tables. The structure you made in SL_BRUTS would never allow you any efficient queries but most trivial.
Check the QUERY EXECUTION PLAN in the last two queries below:
select rdb$get_context('SYSTEM', 'ENGINE_VERSION') as version
, rdb$character_set_name
from rdb$database;
VERSION | RDB$CHARACTER_SET_NAME
:------ | :---------------------------------------------------------------------------------------------------------------------------
3.0.5 | UTF8
create table SL_SPORS (
ID_PERS integer,
ID_SPORS integer,
Primary key (ID_PERS, ID_SPORS)
)
✓
insert into SL_SPORS
select 10, 2 from rdb$database union all
select 10, 3 from rdb$database union all
select 11, 2 from rdb$database union all
select 20, 3 from rdb$database
4 rows affected
select * from sl_spors
ID_PERS | ID_SPORS
------: | -------:
10 | 2
10 | 3
11 | 2
20 | 3
-- CAN this sl_spors_NNN data be NULL ? or not ? what is semantics, what is meaning of it???
create table SL_BROKEN (
ID_PERS integer primary key,
s_SPORS_1 integer NOT NULL,
s_SPORS_2 integer NOT NULL,
s_SPORS_3 integer NOT NULL
)
✓
create table SL_RAWS (
ID_PERS integer,
ID_SPORS integer,
S_SPOR integer NOT NULL,
Primary key (ID_PERS, ID_SPORS),
constraint impossible_over_SL_BROKEN
FOREIGN KEY(ID_PERS, ID_SPORS)
REFERENCES SL_SPORS(ID_PERS, ID_SPORS)
)
✓
-- should throw error over non-existing PERSON - but would it ???
insert into SL_BROKEN
values (-100, 20, 30, 40)
1 rows affected
-- should throw error over non-existing PERSON - and it would!
insert into SL_RAWS
values (-100, 20, 30)
violation of FOREIGN KEY constraint "IMPOSSIBLE_OVER_SL_BROKEN" on table "SL_RAWS" Foreign key reference target does not exist Problematic key value is ("ID_PERS" = -100, "ID_SPORS" = 20)
insert into SL_BROKEN
select 10, 0, 50, 0 from rdb$database union all
select 11, 0, 0, 0 from rdb$database
2 rows affected
select * from SL_BROKEN
ID_PERS | S_SPORS_1 | S_SPORS_2 | S_SPORS_3
------: | --------: | --------: | --------:
-100 | 20 | 30 | 40
10 | 0 | 50 | 0
11 | 0 | 0 | 0
delete from SL_BROKEN where ID_PERS < 0
1 rows affected
create view SL_TRANSPOSE as
SELECT 1 as ID_SPORS, ID_PERS, S_SPORS_1 as S_SPOR from SL_BROKEN
union all
SELECT 2 as ID_SPORS, ID_PERS, S_SPORS_2 as S_SPOR from SL_BROKEN
union all
SELECT 3 as ID_SPORS, ID_PERS, S_SPORS_3 as S_SPOR from SL_BROKEN
✓
select * from SL_TRANSPOSE
ID_SPORS | ID_PERS | S_SPOR
-------: | ------: | -----:
1 | 10 | 0
1 | 11 | 0
2 | 10 | 50
2 | 11 | 0
3 | 10 | 0
3 | 11 | 0
insert into SL_RAWS (ID_PERS, ID_SPORS, S_SPOR)
select ID_PERS, ID_SPORS, S_SPOR from SL_TRANSPOSE
violation of FOREIGN KEY constraint "IMPOSSIBLE_OVER_SL_BROKEN" on table "SL_RAWS" Foreign key reference target does not exist Problematic key value is ("ID_PERS" = 10, "ID_SPORS" = 1)
insert into SL_SPORS
select 10, 1 from rdb$database union all
select 11, 3 from rdb$database union all
select 11, 1 from rdb$database
3 rows affected
insert into SL_RAWS (ID_PERS, ID_SPORS, S_SPOR)
select ID_PERS, ID_SPORS, S_SPOR from SL_TRANSPOSE
6 rows affected
select * from SL_RAWS
ID_PERS | ID_SPORS | S_SPOR
------: | -------: | -----:
10 | 1 | 0
11 | 1 | 0
10 | 2 | 50
11 | 2 | 0
10 | 3 | 0
11 | 3 | 0
select * from SL_RAWS where S_SPOR = 0 -- where S_SPOR IS NULL
ID_PERS | ID_SPORS | S_SPOR
------: | -------: | -----:
10 | 1 | 0
11 | 1 | 0
11 | 2 | 0
10 | 3 | 0
11 | 3 | 0
select * from SL_TRANSPOSE where S_SPOR = 0 -- where S_SPOR IS NULL
ID_SPORS | ID_PERS | S_SPOR
-------: | ------: | -----:
1 | 10 | 0
1 | 11 | 0
2 | 11 | 0
3 | 10 | 0
3 | 11 | 0
db<>fiddle here