Updating a pivot table - laravel

I have a pivot table
id | product_id | user_id
I wish to update this pivot table, I do so by:
Product::find($productId)->attach($userId);
This will produce something like
id | product_id | user_id
1 1 1
But then when I do it again I do not want to update the pivot table if the values already exists.
The above attach method would do something like:
id | product_id | user_id
1 1 1
1 1 1
I know you can use sync, but this removes everything from the table, I do not wish to do this. I also know you can use:
Product::find(1)->user()->updateExistingPivot(1, []);
But this only works when data is in the table.
What Im looking for is a way to do firstOrCreate on a pivot table.


You can add a boolean to your sync method which just adds the value and doesn't remove the existing value.
The code looks like this. The first value can be an int or array.
Product::find(1)->user()->sync([1], false);

Related

relational database in eloquent laravel

hay i have table schema like this
table transaction_fueler
id | code | user_id |user_name| ref_code | area_name
table user_community
user_id | community_id
table user_community is pivot table from table users and community
in table transaction_fueler i want to get community_id from table user_community, depends on user_id* in **transaction_fueler how to get community_id depends on user_id in table transaction_fueler ??
i stuck this.. thanks

i recommend joining the two tables and select the columns you want:
$values = DB::table('transaction_fueler')
->join('user_community', 'user_community.user_id', '=', 'transaction_fueler.user_id')
->select('transaction_fueler.*', 'user_community.community_id')->get();

JPA spring boot insert into child table based on condition

I have one to many relationships in parent and child but I want to insert in the child based on condition only but parent table always.

I think it would be helpful if you could provide us the data structure with example records like:
table 1
column1 | column 2 | column 3
value | value | value
table 2
column1 | column 2 | column 3
value | value | value

select value form one table update value for fetched value in single query

I have two tables request and details.request table id is foreign key for details table I want I have price(321) and request_id(1819AM002) value.I want to fetch value id using request_id in request table update price field value in details table in single query.Is it possible to achieve in single query
request table
id request_id name type
1 1819AM001 XXX A
2 1819AM002 YYY A
Details table
id request_id price
1 2 133

Try this:
DB::table('details')
->join('request', 'details.request_id', 'request.id')
->where('request.request_id', '1819AM002')
->update(['price' => 321]);

two tables with the same sequence

Is possible to have two tables with the same incrementing sequence?
I was trying to do a tree with ID, NAME, ParentID and i have to join two tables.
If i have different id the tree scheme of ID - ParentId will not work.
Table A Table B
ID | NAME | PID ID | NAME | PID
1 | xpto | 0 1 | xpto | 1

If you are doing both inserts at the same time, you can use SEQUENCE.NEXTVAL for the insert into the first table to get a new ID, and then SEQUENCE.CURRVAL for the insert into the second table to reuse the same ID.

I found the answer: "Sequence numbers are generated independently of tables, so the same sequence can be used for one or for multiple tables."
http://download.oracle.com/docs/cd/B19306_01/server.102/b14200/statements_6015.htm
Tanks for your help.

You could have a master table that is nothing but the sequence PK/FK and then have two child tables. Insert a row in the master just to get the sequence and then use that sequence as the PK in the child tables. If the child tables have the same sequence then why is not one table?

create sequence v_seq
INCREMENT by 1
minvalue 1
maxvalue 10;
Sample Image
create table v_t_s_emp(v_id number,vname varchar2(10));
insert into v_t_s_emp values(v_seq.nextval,'krishna');
create table v_t_s_emp1(v_id number,vname varchar2(10));
insert into v_t_s_emp1 values(v_seq.nextval,'RAMesh');
commit;
select * from v_t_s_emp
union all
select * from v_t_s_emp1;

How should i design my tables for concurrent table scan access?

I need to hold multiple pairs of 70,000 rows and perform a comparison difference like operation between them using a minus operator. At any time there could be comparisons (table scans).
I currently have one table with this sort of design:
primary key (sequenced)
foreign key to identify set
key to identify set #1 or set #2
then the data here i need to minus against
The data would look something like this
| PK | FK | Key | Data |
| 1 | 1 | Left | Some data |
| 1 | 1 | Left | Diff data |
| 1 | 1 | Right | Some data |
My query would be:
SELECT data
FROM diffTable
WHERE pk = 1
AND fk = 1
AND key = 'Left'
MINUS
SELECT data
FROM diffTable
WHERE pk = 1
AND fk = 1
AND key = 'Right'
I am fearing the full table scans will monopolise resources and subsequent inserts and minus' will suffer.
How should I design my tables and why?

create index PK_FK on diff_table
(PK, FK, Key);
The query you posted in your question would run very fast with this index.
Btw, the PK column is not, by itself, the primary key. See the other comments. Perhaps you want:
alter table diff_table
add constraint PK_FK primary key (PK, FK, Key);
maybe pick a better name...

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