I am working on a bank application in which a customer can open multiple accounts for different product types like: Insurance, Investment and annuity etc.
Each customer has a profile and we are saving that information in 12 different tables such as : Personal,Contact,Address,Affiliation,Financial,Investment,Asset,Liability,NetWorth and so on.
Now to open each account we have to collect and save same kind of information like for customer profile but we cannot overwrite the customer profile with that as we have to keep track of each accounts information when its submitted to the point when it get opened.
So in terms of solution we think either to have replica of these 12 tables for each account or to save the JSON for each table in one table only which has 12 columns for each of above table and populate UI with that.
Can somebody if have prior experience suggest us how to do this in best way.
I would determine which information will not change between accounts. For example, name, birthday, ssn, etc. These constant fields can form a table called customers. If there are no constant fields, then you can use a placeholder id, which simply helps to associate accounts to the same user.
I would also create a table for Accounts and use the account_id as a foreign key for all your customer information that may change between accounts. Each row in the Accounts table will be owned by a customer from before.
So the relationship between customers and accounts would be one to many, and the relationship between accounts and "account specific customer info" would be one to one.
Related
I'm creating a db schema that involves users that can have multiple users.
I want to register different companies to use the web services.
For example:
user A or B (etc) can signup and create a company account
user A can create multiple accounts of other users with their types, similarly user B
If user A or B create different accounts, how would I know this particular user is belong to User A or B company ? I think user table have many to many relationship with itself (like basic friendship design).
Please suggest the best design .
Ex.
User 3,4 belongs to User A
User 5,6 belongs to User B
In general, I would recommend starting by identifying all the entities you are trying to persist. It sounds like you have two distinct entities in your question. One being "user," which represents a single person. Your second entity is "company." A "user" can belong to a company.
An example of a database design would be one table for users, and one table for companies. In the "users" table, you would want to have a foreign key column that references the primary key (unique id) of the company the user belongs to. If each user can only belong to one company, this becomes a simple one to many relationship.
In short, I would highly recommend treating company accounts separately from user accounts, since they are fundamentally different entities.
In this case let me be more specific about the problem
I've got a peoples table(with customer & supplier) and I've got a users table(for users who can login).
Currently I have this DB structure
Customers -> Organisations -> linked through rel_customer_addresses to address table.
(as 1 customer could have delivery_address, invoice address etc.)
Users -> Tenants -> linked through rel_users_addresses to the address table
(as 1 user could have delivery_address, invoice address etc.)
Now I've got in the invoice table customer_key. The problem is when the user himself is the customer and the invoice is from one of his customers. How do I indicate my web app to look up user and not the customer?
Since you're looking at 2 separate entities (customers and users), I would go ahead and use 2 separate tables and have them share a unique identifier (i.e., username, SID).
That way there's no chance of one seeing information from the other without the appropriate permissions.
There are several ways to control this, but the logic is something like this.
If userID exists in table user, do this.
If userID exists in table customer, do this.
If userID exists in table user AND table customer, do this.
That way you can control the situation completely either independently or together. In other words, you could grant special permissions to userID that is found in table customer, or just make it completely separate (similar to say, how facebook makes a separate 'identity' for pages vs the account it's registered to).
Hope that helps!
Is it better to create tables that store a lot of data that are related to an entity (User for example) or many tables to store said data?
For example:
User Table
Name
Email
Subscription Id
Email Notifications
Permissions
Or
User Table
Name
Email
Subscription Table
User ID
Subscription ID
Notification Table
User ID
Receives?
... etc
Please consider code in this as well, or I would have posted to ServerVault.
From a relational design standpoint what is important is the normal form you're aiming for. In general, if the "column" would require multiple values (subscription_id1, subscription_id2, etc) then it is a repeating group, and that would indicate to you that it needs to be moved to a related table. You've provided very general table and column notes, but taking a cue from the fact that you named "Email Notifications" and "Permissions" with plurals, I'm going to assume that those require related tables.
I want to make an application where there will be different users and each user will have a set of friends which will be put in categories. There will be some default categories, but the user will be able to add his own. I was wondering which will be the best way to do this.
My idea is to have 3 tables - user, friends and categories.
The user table to have fields (one to many) for friends and categories (but I don't know if the user table will need any information about the friends and the categories at all).
The friends table to have a field for categories (one to many) and a field for the user (many to one).
The category table to have fields for user (many to many?) and friends (many to many?).
I'm not sure about the relations, too. I'm using PHP with MySQL and Symfony2 and Doctrine2. Please help!
EDIT
Maybe I haven't described exactly what I need. When you open the app, you see a login form. If you don't have an account, you should register - the registration creates a new user. This user isn't connected with other users (I'm still new to programming and I want something a little easier so it's something like phonebook). Each user has a list of friends and a firend is a row in a table with fields such as name, addres, phone, email, photo, birthday and so on, but they are added by the current user. The friends are not users. Every user is in fact an account with password and username and when you log in there is just a list of friends. So each user creates categories for himself and he has nothing to do with other users and their categories. The category will have only id and name.
So the idea is that you create an account, then create some categories and add friends to them just to have an organiser when you friends are born or where they live, or which is their phone number, but you create them and add the information about them, they are to users themselves. It's not like a social network. Just a notebook where each user can write info about his friends.
First of all, you need to understand the role of intersection tables: if user A labels user B as a friend (i.e. there is a many-to-many relation from user to itself), and you create a new table to represent that relation (the friends table), any additional information about this "friendship" should be linked to that table. So, if a user categorizes his friends in some way, the category applies to friends, not to user. There's no need for a relation between category and user for this specific purpose.
Update: since friends are not users, the friends table will not be an intersection table (and thus have only one reference back to user, denoting the "owner"), but the rest of the answer still applies.
I'm assuming each category will be a row in the category table. Additional information about the category might be added, but it should be limited to that. For instance, if you want to know which user created a category, you could add a foreign key to user labeled for instance "owner" or "created_by". That might be useful if categories created by one user are not to be seen by others.
Finally, you can relate friends with category. If User A can put user B in at most one category, then a foreign key from friends to category should suffice (i.e. a one to many relation). Otherwise, you might need another many-to-many relation, so an additional intersection table should be created (for instance friend_category).
You could avoid this extra table by employing denormalization, having multiple rows in friends where both users are the same (and in the same order) but the category is different (see also this example). Whether this is advantageous or not is beyond the scope of this answer, but IMHO using an extra table is better for now (it might seem more complicated, but it will be easier to maintain in the long run). (Update: if friends is not an intersection table, denormalizing like this is not really an option, so stick with the friend_category table)
In the end, your layout would look like this:
user friends friend_category category
---- ------- --------------- --------
(user fields) <-- user (owner) <-- friend (category fields)
(friend fields) category --> user (owner) --+
^ |
| |
+--------------------------------------------------------------------+
I can suggest the following table set for this (this scheme applies to the phonebook or social network tasks as well):
Table "Users" that stores all the information about users:
UserId
Name
Phone
Address
... (any other fields)
Table "Categories" that stores information about relationship categories:
CategoryId
Name
Table "Relationships" that stores information about relationships between users:
FirstUserId -> Link to Users table
SecondUserId -> Link to Users table
CategoryId -> Link to Categories table
So, any user is able to add new categories, and then reference them when adding new relationship to another person.
If you need to select all user's friends, you will have to:
select fr.* from Relationships r join Users fr on r.SecondUserId = fr.UserId where r.FirstUserId = <Current user id>
I have several entities which respresent different types of users who need to be able to log in to a particular system. Additionally, they have different types of information associated with them.
For example: a "general user", which has an e-mail address and "admin user", which has a workstation number (note that this a hypothetical case). Both entities also share common properties like first name, surname, address and telephone number. Finally, they naturally need to have a (unique) user name and a password to log in.
In the application, the user just has to fill in his user name and password, and the functionality of the application changes slightly according to the type of the user. You can imagine that the username needs to be unique for this work.
How should I model this effectively?
I can't just create two tables, because then I can't force a unique constaint on the user name.
I also can't put them all in just one table, because they have different types of specific information associated to them.
I think I might need 3 seperate tables, one for "users" (with user name and password), one for the "general users" and another one for the "admin users", but how would the relations between these work? Or is there another solution?
(By the way, the target DBMS is MySQL, so I don't think generalization is supported in the database system itself).
Your 3 tables approach seems Ok.
In users table have only ID, username, password,usertype.
In general users table have ID, UserID (from users table), other fields.
Same thing for admin users.
Usertype field will tell you from what table to search for additional info
if(usertype==admin)
select * from admins where userid=:id;
else
select * from general where userid=:id;
Two tables. USERS with user names, first, last, etc. ROLES with roles, and a link back to the user name (or user id or whatever). Put a unique constraint on the user name. Put workstation nbr, email, phone, whatever else you need, in the user table. Put 2 columns in the ROLES table -- USERID and ROLE.
You should decide how much specific information is being stored (or likely to be stored in the future) and make the decision based on that. If there are only a handful of fields for each user type then using a single table is alright.
USERS table (name, type, email, password, genfield1, genfield2, adminfield1, adminfield2)
Make sure to include the type (don't assume because some of the fields particular to that user are filled in that the user is of that type) field. Any queries will just need to include the "AND usertype = " clause.
If there are many fields or rules associated with each type then your idea of three tables is the best.
USERS table (ID, type, name, password)
GENUSERS (ID, genfield1, genfield2)
ADMINUSERS(ID, adminfield1, adminfield2)
The constraints between IDs on the table are all you need (and the main USERS table keeps the IDs unique). Works very well in most situations but reports that include both types of users with their specific fields have to be done in two parts (unioned SQL or subqueries or multiple left joins).
You can solve it with one 'general' users table containing the information thats available for all users and 1 table for every specific user type. In your example you will then need 3 tables.
Users: This table holds only information shared between all usertypes, ie. UserId, Name, Address, etc.
GeneralUsers: This table 'extends' the Users table by providing a foreing key UserId that references the Users table. In addition, information specific to general users are held here, fx. EmailAddress, etc.
AdminUsers: As with GeneralUsers, this table also 'extends' the Users table by providing a foreign key UserId referencing the Users table. In addition information specific to admin users are held here, fx. WorkstationId, etc.
With this approach you can add additional 'specializations' if the need arises by simply adding new tables that 'extends' the Users table using a foreign key reference. You can also create several levels of specialization. If for example admin users are general users as well as admin users then AdminUsers could 'extend' GeneralUsers instead of Users simply by using a foreing key to GeneralUsers instead of Users.
When you need to retreive data from this model you need to which type of user to query. If for example you need to query a GeneralUser you will need something similar to:
SELECT * FROM GeneralUsers
LEFT JOIN Users ON GeneralUsers.UserId = Users.UserId
Or if querying an admin user
SELECT * FROM AdminUsers
LEFT JOIN Users ON AdminUsers.UserId = Users.UserId
If you have additional levels of specialization, for example by having admin users also being general users you just join your way back.
SELECT * FROM AdminUsers
LEFT JOIN GeneralUsers ON AdminUsers.UserId = GeneralUsers.UserId
LEFT JOIN Users ON GeneralUsers.UsersId = Users.UserId
I most definitely would not do a model where you have separate tables as in GeneralUser, AdminUser and ReadOnlyUser.
In database design, a good rule of thumb is "Down beats across". Instead of multiple tables (one for each type), I would create a SystemUsers table, and a Roles table and define a join table to put SystemUsers in Roles. Also, I would define individual roles.
This way, a user can be added to and removed from multiple roles.
A role can have multiple permissions, which can be modified at any time.
Joins to other places do not need a GeneralUserId, AdminUserId and ReadOnlyUserId column - just a SystemUserId column.
This is very similar to the ASP.Net role based security model.
alt text http://img52.imageshack.us/img52/2861/rolebasedsecurity.jpg