How do I prevent combinations or permutaions in a joining table? - mysql

Question

I have the following tables in MySQL Workbench:
MdV, MdV_has_Chain and Chain.
describe MdV
+------------+--------------+------+-----+-------------+-------+
| Field | Type | Null | Key | Default | Extra |
+------------+--------------+------+-----+-------------+-------+
| MdVID | varchar(255) | NO | PRI | NULL | |
| Source | longtext | YES | | NULL | |
| Chains | int unsigned | NO | | 0 | |
| CampaignID | varchar(255) | NO | MUL | No_Campaign | |
+------------+--------------+------+-----+-------------+-------+
describe MdV_has_Chain
+-----------+--------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-----------+--------------+------+-----+---------+-------+
| MdVID | varchar(255) | NO | PRI | NULL | |
| ChainID | varchar(255) | NO | PRI | NULL | |
| Chain_Num | int unsigned | NO | | NULL | |
+-----------+--------------+------+-----+---------+-------+
describe Chain
+-----------+--------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-----------+--------------+------+-----+---------+-------+
| ChainID | varchar(255) | NO | PRI | NULL | |
| Positions | int unsigned | NO | | 0 | |
| VectorID | varchar(255) | NO | | NULL | |
+-----------+--------------+------+-----+---------+-------+
Here they are in the EER diagram.
Currently the tables of interest hold the following mock data:
select * from mdv;
+-------------+-----------------+--------+-------------+
| MdVID | Source | Chains | CampaignID |
+-------------+-----------------+--------+-------------+
| ITS058-M152 | | 1 | C7 |
| ITS058-M182 | | 2 | No_Campaign |
| ITS058-M244 | Rational Design | 1 | C16 |
| ITS058-M253 | Rational Design | 2 | C17 |
| ITS058-M258 | | 1 | No_Campaign |
| TEST | | 0 | No_Campaign |
+-------------+-----------------+--------+-------------+
select * from mdv_has_chain;
+-------------+------------+----------------+
| MdVID | ChainID | chain_position |
+-------------+------------+----------------+
| ITS058-M152 | ITS058-Ch1 | 1 |
| ITS058-M182 | ITS058-Ch2 | 1 |
| ITS058-M182 | ITS058-Ch3 | 2 |
| ITS058-M244 | ITS058-Ch4 | 1 |
| ITS058-M253 | Ch1 | 2 |
| ITS058-M253 | ITS058-Ch5 | 1 |
| ITS058-M258 | ITS058-Ch6 | 1 |
+-------------+------------+----------------+
select * from chain;
+------------+-----------+-------------+
| ChainID | Positions | VectorID |
+------------+-----------+-------------+
| Ch1 | 2 | T343 |
| ITS058-Ch1 | 7 | ITS058-V240 |
| ITS058-Ch2 | 7 | ITS058-V278 |
| ITS058-Ch3 | 1 | R208 |
| ITS058-Ch4 | 6 | ITS058-V352 |
| ITS058-Ch5 | 7 | ITS058-V361 |
| ITS058-Ch6 | 6 | ITS058-V366 |
+------------+-----------+-------------+
To see what chains each MdV has I used the following query:
select mdv.mdvid, group_concat(mdv_has_chain.chainid order by mdv_has_chain.chain_num) as chainid, group_concat(mdv_has_chain.chain_num order by mdv_has_chain.chain_num) as chain_position from mdv inner join mdv_has_chain on mdv.mdvid = mdv_has_chain.mdvid group by mdv_has_chain.mdvid
+-------------+-----------------------+----------------+
| mdvid | chainid | chain_position |
+-------------+-----------------------+----------------+
| ITS058-M152 | ITS058-Ch1 | 1 |
| ITS058-M182 | ITS058-Ch2,ITS058-Ch3 | 1,2 |
| ITS058-M244 | ITS058-Ch4 | 1 |
| ITS058-M253 | ITS058-Ch5,Ch1 | 1,2 |
| ITS058-M258 | ITS058-Ch6 | 1 |
+-------------+-----------------------+----------------+
I was wondering how I would prevent same ChainIds or a combination of them from being entered to a different MdVID? For example how would I prevent the following insert from working:
insert into mdv_has_chain (mdvid, chainid, chain_num) values ("TEST", "ITS058-Ch2", 2), ("TEST", "ITS058-Ch3", 1)
ITS058-M182 already has those ChainIDs, but in different positions. Note that an MdV can have from 1 to N chains. Similarly, how would I allow permutations of ChainIds at different positions, but prevent entries with the same positions from being entered? I don't intend on implementing both things at once. I just wanted to know how I would achieve either individually.
Thank you for you time. Any help is appreciated.