检查MySQL表中是否存在值，然后选择[Laravel 5]

Question

Here is my pivot table project_group:

+-----+----------+------------+----------+---------+
| ids | group_id | project_id | admin_id | user_id |
+-----+----------+------------+----------+---------+
|   4 |      115 |          1 |        1 | [3,4,5] |
|   5 |      115 |          2 |        1 | [5,2,1] |
|   6 |      115 |          3 |        1 | [1,3,6] |

This table represent group linked to the projects....user_id is which users can see projects/group... Is there any way to display correct projects/group only to the users defined in user_id?

Also content in user_id field can be changed....

Answer 1

The best way to handle this would be to first normalize your database. Storing comma separated lists in a cell is allowed, but generally bad practice, as explained in this question.

If you can have multiple users per project, you should have a linking table with a column for project and a column for user, like this:

project_users:
| project_id | user_id |

and you can make (project_id, user_id) a composite primary key.

That way, you can select the users for a project (say, project 1) like this:

SELECT user_id
FROM project_users
WHERE project_id = 1;

Once you have these, you can display the project data only to users whose id is returned in the above list.

I have built an SQL Fiddle that helps demonstrate this visually, if it helps.

It is good to note that this proper normalization gives the opportunity to a lot of useful data as well, as it becomes easier to search for users by project, but also you can search for project information based on a user.