I am creating a site that allows users to view desired 'teams' and can then join them with the click of one button.
I have my users table which contains: user_id, user_name, team_id
Then, I have my teams table which contains: team_id, team_name, team_players
How would I go about having the users to join a group, each user can also only be in 1 team at a time.
If you want each user to be able to join multiple teams, and each team to have multiple users, then you need a "join table."
Table teams_users would contain team_id, user_id. You can make a composite primary key on team_id, user_id (preventing a user from joining the same team twice).
Then you can get a team with:
SELECT * FROM users t1 right join teams_users t2 ON t1.team_id = t2.team_id WHERE t2.team_name = 'the rascals'
Even if you only want players to join one team at a time, you might still want to use the join table in case you ever change your mind. It would be very easy. To only allow one team per user, put a unique constraint on user_id in the join table. If you later decide you want to allow multiple teams, you just remove that constraint.
If a user tries the "join team" action, you simply check for the user_id's existence in the join table.
SELECT * FROM teams_users WHERE user_id = $user_id
If it does exist, you retrieve its matching team_id and tell them, "sorry, you are already in team 'the rascals'. You must leave that team if you want to join another." If they drop their team, you simply do:
DELETE from teams_users WHERE user_id = 5
If they add a team, you just do:
INSERT INTO teams_users ($team_id, $user_id) #// (assuming PHP variables).
The INSERT query will only work if they are not already in a team. If they are you would get an error message. You could also look at "INSERT ON DUPLICATE KEY UPDATE ..." queries. But I would advise against that because you want to warn users before they change teams.
You should start by adding the team_id field to the users table as a foreign key and allow it to be NULL.
Then you would display the team names in an html form with a radio button for each team.
In a PHP file (which should be set to the action of your form) create an if statement based on the values you assigned to each radio button. In each if block, execute a sql UPDATE statement that will add the appropriate group_ID to the right user instance.
Related
I have 5 tables:
user ( user id, user name, etc.. )
role ( role_id, role_name )
user_role ( user_id, roles_id )
form ( form_id, form_name, etc.. )
form_access ( form_id, role_id )
user contains all registered user data.
role contains all different types of roles.
user_role contains which user has which role (all assigned roles are stored)
form contains all form data.
form_access contains data like which user role has which form access(one form can be assigned to many user roles).
I wanted to write a SQL query in PHP to retrieve form name based on the user logged in and his role, e.g. if Admin logs in he should get all forms, if HR logs in he should get forms related to HR only.
I tried this query:
$query = "SELECT ur.role_id, f.form_name, f.form_desc
FROM user_role ur, froms f
WHERE users.id = '".$user."',
users.status ='A',
forms.form_id = form_access.form_id,
from_access.role_id = user_role.role_id,
user_role.role_id = '".$user."'";`
Some one help me out with the correct query?
Since you start from the user_id you'll want to select from user_role and JOIN form_access and form.
SELECT `form`.`form_name` AS `form_name`
FROM `user_role` AS `ur`
INNER JOIN `form_access` AS `fa` ON `fa`.`role_id` = `ur`.`role_id`
INNER JOIN `form` AS `f` ON `f`.`form_id` = `fa`.`form_id`
WHERE `ur`.`user_id` = '".$user."'
PS: Check the table and column names.
You have to use AND .
BUT this should be better with joins.
$query = "SELECT ur.role_id, f.form_name, f.form_desc
FROM from_access
INNER JOIN froms f ON forms.form_id = form_access.form_id
INNER JOIN user_role ur ON from_access.role_id = user_role.role_id
INNER JOIN users ON users.id = user_role.role_id
WHERE users.id = '".$user."'
AND users.status ='A' ";
Your query is entirely broken, the others may have provided you with solutions but I'm going to give you some advice.
You've written an entire query, tried it, and it failed. I write queries all day long but if I write a whole query in Notepad then execute it it's probably going to have some minor error in it somewhere too.
Start from the ground up. You're trying to get a list of forms the user has access to, so lets start with the forms_access table. So what's the most basic starting point? How about:
SELECT fa.role_id, fa.form_id
FROM forms_access fa
Ok, thats overly simplified but if that ran at least we know we're connected to the database.
So we can easily tell which form_ids each role has access to. Now we know our linking table to users is user_roles, so let's add that in:
SELECT ur.user_id, fa.form_id, fa.role_id
FROM forms_access fa
INNER JOIN user_roles ur ON fa.role_id = ur.role_id
So we've joined forms_access to user_roles on the foreign key role_id. Now we can see for every user_id, which role_id they have and which form_ids they can access.
So we're pretty much there, we just need the information from the forms table, so lets JOIN to that too:
SELECT ur.user_id, f.form_name, f.form_desc, fa.form_id, fa.role_id
FROM forms_access fa
INNER JOIN user_roles ur ON ur.role_id = fa.role_id
INNER JOIN forms f ON f.form_id = ur.form_id
Great! Now we have a list of each form_name/form_desc that each user_id can access.
Try the above step by step, if you skip to the end there could well be an error since I have not tested the code, and I don't know for sure that your table definitions match the question. If you do it step by step you only need to check the most recently added line to find the error.
I have just noticed in the question that you also need users.status = 'A', so in the same way as above you'll need to join to the users table on an appropriate foreign key, give it a go.
Now, once you've done all that you need to filter the results to a specific user_id - notice up till this point we haven't bothered with the WHERE clause.
Now don't go adding some variant of WHERE user_id = '$user' right away because then you've introduced 2 potential errors. Instead try adding WHERE user_id = 0 (or some known user_id). Does the query run and the results look correct? Great, now finally try adding in your php variable.
I've currently got two tables:
mems (members):
id,
name,
email,
password,
salt,
achievements_id
achievements:
id,
achievement,
description,
points
I am able to correctly display the data for a user with:
"SELECT * FROM achievements WHERE id IN (SELECT achievements_id FROM mems WHERE name = '$name')";
My question is, how do I add the achievement ID to the user so each user has their own achievement records? Currently if I use an update it just wipes over the old achievement so it only ever displays 1 record.
Say I have 2 achievements and 2 users
User 1 achieves achievement 1, it's viewable and they have achievements_id set to 1.
User 2 achieves achievement 1, it's viewable and they have achievements_id set to 1.
User 1 then achieves achievement 2, it's viewable but now they have achievements_id set to 2.
I have no clue how to do this. I know what I want to do, but no clue how to design the database to have each user having their own records of achievements.
I originally did it where achievements table had a member_id and I'd concat the other users ID into their, dodgy but it semi-worked.
Any help? Sorry if I am making no sense.
It sounds like what you need is to model a many-to-many relationship (many users can share the same achievement - ie. be linked to the same entitiy in the achievements table; while a single user can have multiple achievements). This is usually done using an extra table. Let's call it: Members_Achievements_Map.
CREATE TABLE Members_Achievements_Map (
MemberID,
AchievementID
)
This table would link entities from the members table to entities in the achievements table.
The way I would go about this would be to create another table to hold the users achievements.
So basically another table that looks like such:
UserAchievements:
userID, achievementID
That way you can join the tables like:
SELECT * FROM achievements a
INNER JOIN userAchievements uA ON uA.achievementID = a.id
INNER JOIN users u ON uA.userID = u.id
That will give you all the users for all the different achievements.
Hope that helps!
From what I've been reading online, I understood that it's better to split the data into more tables, if possible because of the access times.
Right now I have a table in which I am storing usernames, passwords and join date
This is how my table looks:
'user'
'user_id INTEGER UNSIGNED NOT NULL AUTO_INCREMENT,
user_username VARCHAR(80) NOT NULL,
user_password VARCHAR(255) NOT NULL,
user_join_date INTEGER UNSIGNED NOT NULL,
PRIMARY KEY (user_id) ');
I am trying to create a new table called profiles in which I want to store first name, last name, email, age and gender. What I think is that I need a one-to-one relationship, so I should be using the user_id but I'm not really sure how to implement it.
Should I create another table called profiles with
profiles
profiles_id
first_name
last_name
email
age
gender
and another one which should be the relationship ? e.g.
user_profiles
----------
user_id
profiles_id
Is this right? How would the SQL look for the user_profiles?
Thanks
Don't split the tables. Just add the new columns to your existing user table. You might find later on that splitting tables is a good idea based on actual queries and usage patterns but until you have that kind of data, keep things simple.
If you must create a profile table, don't create a user_profiles table. That would allow an m-to-n relationship which is probably not what you want. A simple user_id column in profiles is better. In fact, it could be both a foreign key and the primary key to make sure that each user row only have one and only one profile row (although by splitting the tables you might still have a user with no profile).
Usually, you create an association table, like user_profiles you have described when one user could have more than one profile, and/or one profile could belong to one or more user.
As you have said, here you have a one-to-one relationship between user and profile. So, you can simply add a user_id column to your profile table, and define it as a foreign key to user table.
Then, a simple JOIN will allow you to query both tables at the same time:
SELECT u.*, p.*
FROM user u
JOIN profile p ON u.user_id = p.user_id
Add a new field in the User table, ProfileId, and set it as Foreign Key (FK). Each time you create a User, you have to assign to it a profile (which will be the ProfileId PK from profile table).
If you want to see also the profile information of a user, you have to do a join
Select username, first_name,second_name
From user u, profile p
Where u.profileId = p.profileId
this
user_profiles
----------
user_id
profiles_id
is used in a many-to-many relationship. By example, you want to assign to an admin some privileges, but those privileges can be also assigned to more admins. Then, you have to create a 3rd table to solve this problem. Here is an example, but you don't need to do this.
You could add a user_id field to your profiles table and JOIN the tables on user_id.
SELECT user.user_username, ..., profiles.first_name, ...
FROM user
INNER JOIN profiles
ON user.user_id = profiles.user_id
This should fetch data combining information from those rows where the JOIN condition is met (i.e. user.user_id = profiles.user_id).
It is true that having more than one tables is a good idea. I am not sure what you mean about access time, but there are other advantages.
- Your users database containing passwords etc is "sacred", you never change its structure and you limit the rights to it (read, write) to the strict minimum.
- You can then have several "satelites" tables such as profiles, private messages, etc which are more flexible, less sensitive and which you can change all the time.
About your question per se, there is no need for a separate table with the relationships. In fact is a very bad idea which will complicate your queries and doesn't have any advantage. Instead, in your profiles database you will have one column that refers back to the user id.
users
--------
id
user_name
email
password
users_profiles
---------
id
user_id
favourite_animal
Table user
user_id |user_username |user_password |user_join_date |profile_id
Table profile
profile_id |first name |last name |email |age |gender
When selecting a user by user id:
SELECT u.*, p.* FROM user AS u INNER JOIN `profile` AS p ON u.profile_id = p.profile_id WHERE u.user_id = 1
But a user should only one gender, one age, one name and surname. Maybe e-mail adresses might be many. I suggest you there is no need to join tables which have a 1-to-1 relation. Instead merge those tables.
The site I'm working on has 3 different types of users: admin, applicants, reviewers. Each of these groups will have some basic info that will need to be stored (name, id, email, etc) as well as some data that is unique to each. I have created a users table as well as a table for each of the specific groups to store their unique data.
users: id, f_name, l_name, email, user_type
users_admin: id, user_id, office, emp_id
users_applicant: id, user_id, dob, address
users_reviewer: id, user_id, active_status, address, phone
If a user with user_type of "1" (applicant) logs in I will need to JOIN to the users_applicants table to retrieve their full record. I tried using a UNION but my tables have vastly different columns.
Is there a way to, based on a user's type, write a conditional query that will JOIN to the correct table? Am I going about this completely the wrong way?
Thank's in advance for your help!
Well, in the end your tables are already flawed. Why even have a table for each type? Why not put all those fields into the users table, or maybe a user_details table (if you really want an extra table for non-general data fields)? Currently, you're actually creating 4 independent user tables from a relational point of view.
So why do the type-tables have a surrogate key? Why isn't the user_id already the (only) primary key?
If you changed that, all you would need is the user id to retrieve the data you want, and you've already got that (or you wouldn't even be able to retrieve the user type).
Either you do it programmatically, or you can do this with a series of CASEs and LEFT JOINs.
For simplicity's sake let's do this with a table users where you can have a user of type 1 (normal user), 2 (power user) or 3 (administrator). Normal users have an email but no telephone, power users have an address and a field dubbed "superpower", and administrators have a telephone number and nothing else.
Since you want to use the same SELECT for all, of course you need to place all these in your SELECT:
SELECT user.id, user.type, email, address, superpower, telephone
and you will then need to LEFT JOIN to recover these
FROM user
LEFT JOIN users_data ON (user.id = users_data.user_id)
LEFT JOIN power_data ON (user.id = power_data.user_id)
LEFT JOIN admin_info ON (user.id = admin_info.user_id)
Now the "unused" fields will be NULL, but you can supply defaults:
SELECT
CASE WHEN user.type = 0 THEN email ELSE 'nobody#nowhere.com' END AS email,
CASE WHEN user.type = 1 OR user.type = 2 THEN ... ELSE ... END as whatever,
...
Specific WHERE conditions you can put in the JOIN itself, e.g. if you only want administrators from the J sector, you can use
LEFT JOIN admin_info ON (user.id = admin_info.user_id AND admin_info.sector = 'J')
The total query time should not be too bad, seeing as most of the JOINs will return little (and, if you specify a user ID, they will actually return nothing very quickly).
You could also do the same using a UNION, which would be even faster:
SELECT user.id, 'default' AS email, 'othermissingfield' AS missingfieldinthistable,
... FROM user JOIN user_data ON (user.id = user_data.user_id)
WHERE ...
UNION
SELECT user.id, email, 'othermissingfield' AS missingfieldinthistable,
... FROM user JOIN power_data ON (user.id = power_data.user_id)
WHERE ...
UNION
...
Now, if you specify the user ID, all queries except one will fail very fast. Each query has the same WHERE repeated plus any table-specific conditions. The UNION version is less maintainable (unless you generate it programmatically), but ought to be marginally faster.
In all cases, you'll be well advised in keeping updated indexes on the appropriate fields.
Instead i will suggest you reconstruct you tables structure like this.
Create a table
users_types :
id
type
Then create another table users with a foreign key
users :
id
f_name
l_name
email
office
emp_id
dob
address
active_status
phone
users_types_id
And now when you need to insert data insert null in the fields which are not required for a particular user. And you can simply fetch records on the basis of id. Also using left join will give you the name of user type.
Okay I am making a profile page where I will call on all of the user's information. Within the website users will gain points and earn badges. I have something like 35 badges. Rather than have a row in my users table for every badge(yes/no to decide whether user has earned badge) for every single user, I was wondering how I could do this without blowing up my users table.
I have a badge table with index, name, description, and photo. I was wondering can I make a single row in my users table for badges and separate badge numbers by ",". Then decipher the badges so they all print on the page. I feel I can do this but don't know how.
Please help. Open to other suggestions
You are describing a many-to-many relationship; use a junction table to represent it.
Create a table of users and a table of badges. Then create a Users_Badges table with user_id and badge_id as foreign keys in it (together they will form a composite key).
you can create table structures like these.
table structures
users
userId
userName
badges
badgeId
badgeName
user_badges
userId
badgeID
-- returns given users all badges within single row and comma seperated field.
select group_concat(b.badgeName) as usersAllBadges
from user_badges ub
inner join users u on u.userId = ub.userId
inner join badges b on b.badgeId = ub.badgeID
where ub.userID=1
-- returns given users all badges seperate rows.
select b.badgeName
from user_badges ub
inner join users u on u.userId = ub.userId
inner join badges b on b.badgeId = ub.badgeID
where ub.userID=1
You tagged php so I am assuming php
explode(',',$data);
http://www.php.net