I have a user table which has all details like username, email id, birth date, contact no. A user has friends and these friends may belong to certain groups like for e.g close friends, family, colleagues which user has created. A friend may belong to one group or many groups or none of the groups at all.
I need to set a certain privacy related to the attributes of the user table for friends or group of friends. Like for e.g. my group of family can only view my birth date or colleagues can view only my email id but no other details like birth date or contact number.
How can I achieve this privacy?
Thanks.
Having a separate table for every "special" attribute, could lead you to have a lot of tables. On the other hand, you can use the entity-attribute-value model. This way you will have one table for users, one table for all the user's attributes, and one table for the values associated to an specific user and his attributes.
User
id
idGroup
Attribute
id
description
Value (User-Atribute)
idUser
idAttribute
value
In addition, you can relate the attribute table and the group table. By relating these two tables you can specify which attributes will be visible for each group. Don't forget to relate the user table and the group table.
Group
id
description
Access (Group-Attribute)
idGroup
idAttribute
Shouldn't you try to handle that logic on the code, instead of the database? It seems that this is related to business logic instead of the actual data model.
If you want to go forward with this approach have you considered having the private data in a separate table?
Related
We have a system with two main roles: service provider and customer. The provider side is users like doctors, nurses, and caregivers. The customer side is just the customer. all user types contain some common data and some uncommon data. in the current system, we have a table for each user type, and for common data, we have User table. currect system ERD is:
https://s4.uupload.ir/files/screenshot-20210710165449-1007x662_tpwd.png
in the current system, we have a lot of tables and we think about reducing them. our vision is to bring all user types in a single table called User and instead of a lot of tables, we have more columns. of course in some users, we have empty cells that do not belong to this user type.
I have 4 questions:
is it ok to bring customers and providers to a table like User?
what is the optimal number of columns in a table?
load a row with a lot of columns OR relation between different tables?
provider type should be a separate table or can be an enum?
It is best to put all users in single table. So when you check login there is less place to do mistake. When selecting user you dont need to use SELECT * FROM... You can use SELECT id, username, name FROM...
Dont put too many columns, if there is some data which you dont need when searching or displaying users, you can create helper table "user_meta" with dolumns user_id, meta_key, value where user_id and meta_key are primary key
Answered by first 2 answers
Provider type should be enum if there will not bee needs to expand with additional types.
I have two tables in my database..one is candidates_details and another one is users..in the users table i have two types of users one is vendor and another one is user..they both have same user_id column...and i have that user_id column in my candidates_details table..
So what i want to do is when vendor post candidate_details by using form ..i want to store that user_id
(where user_type_id=1)
in candidates_details table automatically..
Can anyone help me..Thanks in advance..
Let me help you out by giving a pictorial example. Assume you have two tables users and candidate_details. In users you are keeping record of all the registered users along with their types. In Candidate Details you are keeping their profile data. You create another table where you keep user types Be it vendor, contractor, supplier etc.
Now when you create your form to post data in your admin panel or which ever interface you have. Just create a dropdown for user_types, get the type id and add the user. With the type id in your users table you can easily query which type of user that is.
Now for saving that user's profile information in candidate_details table you only have to provide user_id. So creating one more table will normalize your db schema and saves a lot of hustle in your query building.
Hi currently i have 3 tables:
users
|id|name|email|password|last_login|created_at|
user_groups
|user_id|group_id
groups
|group_id|name|email|password|last_login|created_at|
Group can login so it when i can view statistics for specific all it users, that's why i put email and password too.
the problem is users and groups got almost everything same. 1 group can contain many users.
Is there anyway to make this more normalize and user still have their specific groups?
I would just use the user authentication to detect whether the user belongs to any group or not. That way you don't need all these extra fields for the group.
If you only want one specific user to be able to look at the group statistics you could add an admin_id to the user_groups table (which would relate to a user id)
I'm trying to figure out the best way to design these tables for a website I'm making for a school club. I want to set it up so each user can have multiple emails, phone numbers, and addresses tied to their account. To do this I tried to tie all these things to a contacts table and store the contacts id in the users table as a foreign key. The contacts id is also a foreign key in the emails, phone numbers, and addresses table. Is this a feasible way of relating these tables or should I just cut out the middle man (contacts table) and store the user id in the emails, phone numbers, and addresses tables?
Just in case my description of the relationships weren't enough, here is an ERD for the tables:
Sorry for such a "noob" question, it's been a while since I had to build a database with more complexity than 2 tables. Any general tips for database design are very much welcomed as well.
All you need to do is remove the Contacts table and store the user_id in the tables on the right, rather than contact_id.
Remove contact_id from Users as well.
I have dealt with this very question in the past. We did it wrong and we were sorry.
The determining factors should be these:
Will you have any other category of person that isn't a user, for whom you need to store contact information?
Will those kinds of persons somehow be "fungible" with users?
If you answer both these questions "yes," keep your contact table. Otherwise get rid of it.
The mistake made by a team I worked on was our answer to the second question. We had medical patients and doctors/nurses/etc as our categories of people. We stored their contact information together. But we shouldn't have done that because patients' contact information is very sensitive and confidential, but health care provider information is much less so. We were always wishing we didn't have the two kinds of data in just one set of tables after the system became successful.
Unless you can convince yourself you need your contact table, get rid of it, I say!
Yes I would cut out the midle man:
Although I was tempted to go the 'contact_type' route, I have found that there are usually validations and different data types which become more complicated when the contact is generic. For instance a table that has address fields is not the same as a phone number and having both presents more complexity and less readability.
This model focuses on simplicity, e.g. a user has many emails and an email belongs ot a user.
According to me you can design DB accordingly
Table 1 : Users
UserID //PK
Name
Table 2 : Contacts
ContactID //PK
UserID //FK to Users
ContactTypeID // FK to ContactType
Value
Table 3 : ContactType
ContactTypeID //PK
ContactTypeName
Description
Table 1 is pretty clear stores user information
Table 3 holds information about contacttype i.e email, home phone, mobile, home address, shipping address, etc
Table 2 holds information about user, contact type and its value
like cinatacttypeid corresponds to mobile than value is , etc.
Assuming I want to have a web application that requires storing user information, images, etc as well as storing status updates or posts/comments would I want to separate tables?
For example if I have a "users" table that contains users information like passwords, emails, and typical social networking info like age, location etc. Would it be a good idea do create a second table("posts") that handles user content such as comments and/or post?
Table one: "users"
UserID
Username
Age
etc.
Table Two: "posts"
PostID
PostContent
PostAuthor
PostDate
etc
Is this a valid organization? Furthermore if I wanted to keep track of media should I do this in ANOTHER table?
Table Three: "media"
ID
Type
Uploader
etc.
Any help is much appreciated. I'm curious to see if I'm on the right track or just completely lost. I am mostly wondering if I should have many tables or if I should have larger less segregated tables.
Also of note thus far I planned on keeping information such as followers(or friends) in the 'users' table but I'm not sure that's a good idea in retrospect.
thanks in advance,
Generally speaking to design a database you create a table for each object you will be dealing with. In you example you have Users, Posts, Comments and Media. From that you can flesh out what it is you want to store for each object. Each item you want to store is a field in the table:
[Users]
ID
Username
PasswordHash
Age
Birthdate
Email
JoinDate
LastLogin
[Posts]
ID
UserID
Title
Content
CreateDate
PostedDate
[Comments]
ID
PostID
UserID
Content
[Media]
ID
Title
Description
FileURI
Taking a look above you can see a basic structure for holding the information for each object. By the field names you can even tell the relationships between the objects. That is a post has a UserID so the post was created by that user. the comments have a PostID and a UserID so you can see that a comment was written by a person for a specific post.
Once you have the general fields identified you can look at some other aspects of the design. For example right now the Email field under the Users table means that a user can have one (1) email address, no more. You can solve this one of two ways... add more email fields (EmailA, EmailB, EmailC) this generally works if you know there are specific types of emails you are dealing with, for example EmailWork or EmailHome. This doesn't work if you do not know how many emails in total there will be. To solve this you can pull the emails out into its own table:
[Users]
ID
Username
PasswordHash
Age
Birthdate
JoinDate
LastLogin
[Emails]
ID
UserID
Email
Now you can have any number of emails for a single user. You can do this for just about any database you are trying to design. Take it in small steps and break your bigger objects into smaller ones as needed.
Update
To deal with friends you should think about the relationship you are dealing with. There is one (1) person with many friends. In relation to the tables above its one User to many Users. This can be done with a special table that hold no information other than the relationship you are looking for.
[Friends]
[UserA]
[UserB]
So if the current user's ID is in A his friend's ID is in B and visa-verse. This sets up the friendship so that if you are my friend, then I am your friend. There is no way for me to be your friend without you being mine. If you want to setup the ability for one way friendships you can setup the table like this:
[Friends]
[UserID]
[FriendID]
So If we are both friends with each other there would have to be 2 records, one for my friendship to you and one for your freindship to me.
You need to use multiple tables.
The amount of tables depends on how complex you want your interactive site to be. Based on what you have posted you would need a table that would store information about the users, a table for comments, and more such as a table to store status types.
For example tbl_Users should store:
1. UserID
2. First Name
3. Last name
4. Email
5. Password (encrypted)
6. Address
7. City
8. State
9. Country
10. Date of Birth
11. UserStatus
12. Etc
This project sounds like it should be using a relational DB that will pull up records, such as comments, by relative userIDs.
This means that you will need a table that stores the following:
1. CommentID (primary key, int, auto-increment)
2. Comment (text)
3. UserID (foreign key, int)
The comment is attached to a user through a foreign key, which is essentially the userId from the tbl_Users table. You would need to combine these tables in an SQL statement with your script to query the information as a single piece of information. See example code
$sql_userWall = "SELECT tbl_Users.*, tbl_Comments.*, tbl_userStatus FROM tbl_Users
INNER JOIN tbl_Comments ON tbl_Users.userID = tbl_Comments.userID
INNER JOIN tbl_UserStatus ON tbl_Users.userID = tbl.UserStatus
WHERE tbl_Users.userID = $userID";
This statement essentially says get the information of the provided user from the users table and also get all the comments with that has the same userID attached to it, and get the userStatus from the table of user status'.
Therefore you would need a table called tbl_userStatus that held unique statusIDs (primary key, int, auto-incrementing) along with a text (varchar) of a determined length that may say for example "online" or "offline". When you started the write the info out from e record using php, asp or a similar language the table will automatically retrieve the information from tbl_userStatus for you just by using a simple line like
<?php echo $_REQUEST['userStatus']; ?>
No extra work necessary. Most of your project time will be spent developing the DB structure and writing SQL statements that correctly retrieve the info you want for each page.
There are many great YouTube video series that describe relational DBS and drawing entity relational diagrams. This is what you should look into for learning more on creating the tye of project you were describing.
One last note, if you wanted comments to be visible for all members of a group this would describe what is known as a many-to-many relationship which would require additional tables to allow for multiple users to 'own' a relationship to a single table. You could store a single groupID that referred to a table of groups.
tbl_groups
1. GroupID
2. GroupName
3. More group info, etc
And a table of users registered for the group
Tbl_groupMembers
1. membershipCountID (primary key, int, auto-increment)
2. GroupID (foriegn key, int)
3. UserID (foriegn key, int)
This allows users to registrar for a group and inner join them to group based comments. These relationships take a little more time to understand, the videos will help greatly.
I hope this helps, I'll come back and post some YouTube links later that I found helpful learning this stuff.