Closed. This question is opinion-based. It is not currently accepting answers.
Want to improve this question? Update the question so it can be answered with facts and citations by editing this post.
Closed 7 years ago.
Improve this question
Let's say I have a User model and a Favorite model. I want to know how many favorites a user has.
I see that you can accomplish this in two ways.
Atomically increment a counter attribute on the user model when a favorite is created. Access using user_instance.favorite_count
Query the favorite count for the user: user_instance.favorite_set.count()
I would imagine that as the DB grows, counting becomes more expensive.
Which implementation is more scalable?
I smell some premature optimization here. Databases are extremely good at counting things. Unless you have measured and are seeing some identifiable slowness, you should not attempt to denormalize: it is difficult to get right and always at risk of getting out of sync. Go with the query; and don't forget you can use aggregation to query the counts for a queryset of users at one time.
Related
Closed. This question is opinion-based. It is not currently accepting answers.
Want to improve this question? Update the question so it can be answered with facts and citations by editing this post.
Closed 5 years ago.
Improve this question
I am about to develop a small cms\forum. Multiple customers are going to have there own access where the customers can communicate white them.
What is best practices- to make separate SQL db to each customer's cms data or one big to contain all the customers data?
As I cannot comment, so I can only type here.
It is strange that you would like to have separate database for each customer and it seems impossible to manage multiple db for just one purpose or function. For example, how could you identify which db belong to which customer? Also, do you expect to have many resource to allocate to each customer? a db simply waste if the customer is not active.
So, I suggest you to use one db to manage all the customers data which is normal solution.
Closed. This question is opinion-based. It is not currently accepting answers.
Want to improve this question? Update the question so it can be answered with facts and citations by editing this post.
Closed 7 years ago.
Improve this question
Optimization was never one of my expertise. I have users table. every user has many followers. So now I'm wondering if I should use a counter column in case that some user has a million followers. So instead of counting a whole table of relations, shouldn't I use a counter?
I'm working with SQL database.
Update 1
Right now I'm only writing the way I should build my site. I haven't write the code yet. I don't know if I'll have slow performance, that's why I'm asking you.
You should certainly not introduce a counter right away. The counter is redundant data and it will complicate everything. You will have to master the additional complexity and it'll slow down the development process.
Better start with a normalized model and see how it works. If you really run into performance problems, solve it then then.
Remember: premature optimization is the root of all evils.
It's generally a good practice to avoid duplication of data, such as summarizing one data point in another data's table.
It depends on what this is for. If this is for reporting, speed is usually not an issue and you can use a join.
If it has to do with the application and you're running into performance issues with join or computed column, you may want to consider summary table generated on a schedule.
If you're not seeing a performance issue, leave it alone.
Closed. This question needs to be more focused. It is not currently accepting answers.
Want to improve this question? Update the question so it focuses on one problem only by editing this post.
Closed 7 years ago.
Improve this question
Apologies in advance if this is a stupid question. I've more or less just started learning how to use SQL.
I'm making a website, the website stores main accounts, each having many sub-accounts associated with them. Each sub-account has a few thousand records in various tables associated with it.
My question is to do with the conventional usage of databases. Is it better to use a database per main account with everything associated with it stored in the same place, store everything in one database, or an amalgamation of both?
Some insight would be much appreciated.
Will you need to access more than one of these databases at the same time? If so put them all in one. You will not like the amount of effort and cost 'joining' them back together to do a query. On top of that, every database you have needs to be managed, and should you need to transfer data between them that can get painful as well.
Segregating data by database is a last resort.
Closed. This question is opinion-based. It is not currently accepting answers.
Want to improve this question? Update the question so it can be answered with facts and citations by editing this post.
Closed 8 years ago.
Improve this question
i'm wanting to write data into memory only for a temp time. the format is essentially the same as an sql table with say 5 columns and 1,000 rows, give or take. simply i want to store this data and run queries against it to make calculations, sorting it, querying it to then produce chart reports and excel data.
I looked at custom psobjects and then sql and i can't see why i'd use custom psobjects over sql, what do you think?
I also couldn't see that adding multiple rows as such, using psobjects was as straight forward as adding another row in sql.
thanks
steve
I guess it depends on what you're more comfortable with, but if you're going to do it in Powershell then using PS custom objects seems like a logical choice since the cmdlets were designed to work with those.
Closed. This question is opinion-based. It is not currently accepting answers.
Want to improve this question? Update the question so it can be answered with facts and citations by editing this post.
Closed 9 years ago.
Improve this question
I am designing a database for a form which contains many select boxes and check boxes lists.
I am unsure whether to populate these lists from a table in the database or from the select html text.
as part of db design best practice which is the preferred method.
If you expect the form elements (checkboxes, lists) are likely to change often, or are conditional (based on configurable permissions/roles), then they should come from a database.
However, if they are mostly static (rarely change, not dependent on configurable permissions), then you should hard-code them. The big benefit of hard-coding them is less traffic on your DB. This will yield the best performance.