best structure of my table in Perfomance way: [closed] - mysql

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i have two different database schemas
First Structure is :
table 1 : country_master
Column name: id(primary key) country_name
table 2: State_master
Column name: id(primary key) State_name Country_id(foreign key of country_master)
table 3: City_Master
Column name: id(primary key) city_name State_id(foreign key of State_master)
Second Structure is:
table 1 : Master_table
Column name: id(primary key) name
table 2 : Sub_master
Column name: id(primary key) name master_id(Foreign key of master Table) subid(id of Sub_master)
Record of first structure
table: Country_master
1 india
2 UK
3 USA
table:State_master
1 gujarat 1
2 MP 1
3 Up 1
table:City_master
1 ahmedabad 1
2 surat 1
Record of structure 2:
table:master_table
1 Country
2 City
3 State
table:master_table
1 india 1 0
2 UK 1 0
3 USA 1 0
4 Gujarat 3 1
5 MP 3 1
6 Up 3 1
7 ahmedabad 2 4
8 surat 2 4
now my question is what is best schema of my tables for performance:

Answer 1

The second structure gonna be create more issue regarding performance point of view.
As the child table have all references, it is difficult to maintain. Consider the scenario, where you need to mark for the "capital" of each state having the crores of data, then what would you do to add one more column into existing table and update each of one? No not obviously, instead the better job is to separate all the cities, states and countries in a separate table and use in query having joins, so join performes on primary key. And the most important is, these data not gonna be change often means these remains constant most of the times. These are called lookups, hence you need to separate in a table. The first structure is good in a first appearance because dataset is too small, as data increases, that gonna create problems, hence the better is to use the first structure.

Answer 2

You could probably achieve the same performance by adding the right indices on the tables.
For ex: if one if your queries is search for all states in a country you would need to create an index on the master and sub id of the sub table in the second structure.

Answer 3

I think your second table structure is not complete.here parentid can be non-clustered index,type can be non-clustered index.table variable is just example to show
Declare #t table (id int identity(1,1) primary key,names varchar(100)
,parentid int,[type] int)
--where [type] can be enum 1=country,2=states,3 city
insert into #t values ('india',null,1) ,('gujrat',1,2)
,('surat',2,3) ,('Bihar',1,2),('Pakistan',null,1)
;with CTE as
(
select * from #t where id=1
union all
select a.* from #t a inner join cte b on a.parentid=b.id
)
select * from cte
IMHO,Advantage is that if city is not mandatory.then in first table
structure you have to use left join. In second example whatever be the
requirement you can always use Inner join.Hence second structure is
fast.Also second is more flexible.Just one proc will do
.
Though let other comment .