Relate rows with tables [duplicate] - mysql

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So i have a website where users create their own 'shops' and then they can put items in the shops, so would it be practical to create a table for each user's shops or should I just add user IDs to posts?

You should add user ids to shops/posts. There are numerous reasons why you do not want to have separate tables for each user:
MySQL is designed to handle tables with lots of rows, not lots of tables with the same structure.
Structuring queries that goes across tables will require combining lots of different tables.
A small change to the data structure, such as adding a new column, becomes a nightmare.
Foreign key references to the shops becomes impossible.
If the data for a user doesn't fill a single data page, you end up wasting a lot of memory.
There are some reasons why splitting data into separate tables might be necessary. Here are some possible reasons:
Access is more easily managed at the table level than at the row level.
Replication of the data for each user might have different requirements.
An external entity requires that the data be in separate tables or databases.
However, the first set of reasons seems to weigh much more heavily to single table/entity structures. These more advanced concerns do not appear to be an issue.

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What is a better way to manage same database tables for multiple products/environment? [closed]

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I have multiple products/environment, like Google has drive, docs etc.
One common Auth server is there which will contain users table.
But I have roles table related to each product, which contains roles for user for respective product.
Now how to manage this roles table?
I have following ways to do this, which one is better and why?
Create common table roles in main schema, and have product ID to link the records in table.
Have different table in same schema with prefix product_name. Eg. prod1_roles, prod2_roles.
Have different schema in same database, for Eg. product1 schema contains product1 roles table and so on.
Which of the above approach should I go with? Creating different database for 1 table is not feasible for me. So I want to go with any one of above or any other better approach will be appreciated.
If all your tables could have the same columns, is better to have just one, in a central schema, using an product_id. You will use the same pattern for login all your users at different products. This make your security layer easyer to control. And this is an important feature.

database normalization a one to one relationship [closed]

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I have two tables in my db:
Marketers:
Id, Username, Password, Email
Stores:
Marketer Id, 1 Store, 2 Store, 3 Store, 4 Store, ...., 10 store
there is the names of 10 stores for every marketer in Stores table.
So there is a one to one relationship between these two tables. right?
I'm wondering if it would be better to just combine these two tables or not.
I wan't to send a lot of query for the second table (Stores tables). so I though this would be better if I separate these two cause I rarely need the information stored in 'Marketers table'.
From a good design perspective, you should keep these tables as separate.
for your current requirements,
if you do not need data from Marketers so often, why do you need to include that in Stores. you would just end up fetching extra data each time.
say if tomorrow if some new info and the mapping changes to one to many or vice versa, your current design will work perfectly fine.
and of course from future maintainence view, it is easier to update current design.
although, i would also, suggest you to add an independent primary to Stores table also.

Multiple databases or multiple row tables [closed]

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I have a question about how big companies manage a database structure, let's say if i have an ecommerce app something like shopify which is the best approach you take:
a) When a new user creates an account a new database with his tables is created specifically for that user (i think if for some reason this database fail the other databases of other users remain working)?
b) When a new user creates an account Instead of create a new database, the app just create a new row in a table for his login and then all the products of all users are in the same table and only the user_id is the difference between one product of a store and another.
Thanks in advance.
Yeah, you should go for the second option (b), for alot of reasons:
1. Most of the data in your database shall be accessible for all users, so you don't want to have the same data stored in multiple places.
2. Sooner or later, you will come up with features where you want to share or link data between different users, etc.
3. Your first choice (a) would be extremely resource consuming compared to the second choice (b).
4. Well, the list can go on and on... :)
Obviously, the second choice - much more efficient and smarter.
Think about the number of the users, let's say 10k for example.
you realy don't want to handle this mass of tables!
I would go with Option B. This will reduce your work load and help in reporting needs down the road. Just make sure you use a robust database design to handle load when writing to database tables.

Is it a bad practice to display a detailed information about a record in table [closed]

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I like to use tables as it will allow me to organize the data in a better manner. But now inside my application I am using tables to represents different data which can give misleading meaning. for example I am displaying the list of all record in a table such as:-
Then I am also displaying the details of each record in a table where rows will have different context:-
For me the tables seems clear ,, but am I using tables in the right context?. Or usually table rows should represents the same type of objects (for example different organizations, not different properties about an organization )? ?
Well. Most systems show information using tables. Look at any forum software, for instance. In terms of user-friendliness, you could emphasize your header rows on your top table. On your bottom table, you could emphasize the left row (a darker background or stronger font).
In my opinion using tables in this scenery is ok. All data is exhibited in simple and clear way.

Mysql table design : table roles [closed]

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I have a table called enterprise in my database. If the enterprise expresses its demand to my company, the enterprise will become our prospection. And after, if the enterprise accept my company's proposal, we will sign the contract, and enterprise becomes out client.
Now, I have created 3 tables which are enterprise, prospection, client.
So, how should I design the database?
One approach would be to have a table Companies, and the three tables you already have. All three tables have field CompanyId that has a foreign key constratint linkining it to the companies table. This design has the advantage that you have to keep the company information in one place and there is no duplication.
Another way would be to have a field in the companies table, that marks them as an enterprise, prospect, or client.
Which design you should choose largely depends on information for the different classes. If you thinking along inheritance (i.e. a client is a prospect is a enterprise) than the company table suffices. However, if ther is a large amount of information and the information is different for each of the three classes than the first approach would be better.
You should, however, always try to keep the information in one place, i.e. in one field/table (= fully normalized). In some cases you can deviate from this principle for performance reasons, but keep in mind that this also means a higher maintenance overhead - you have to update n tables when a value changes.