I am new to Amazon Dynamo DB, I have created a user table and address table.and I want to retrieve all users with their particular address as I have assigned user_id in address table to each address. So how can I get user info with address with one query rather than querying both table and merge after. Is their any way like in MySQL we can use JOIN?
Dynamodb is not meant for these types of queries; especially aggregation queries are not ideal. DynamoDB is mainly good for fast lookups for predefined access patterns (e.g. get all items in shopping cart for user ID X).
Since addresses are unique properties of users, you might be able to add an attribute to the user ID table. So basically you have one table with all user data and their properties, including address, that you can query by user ID.
If you need to support different queries I'd suggest you note them all down first before deciding on your data model. (E.g. get all users and sort by last name, get all users living in city X). If the data model in dynamodb is too complex to support all these access patterns you might need to change to a SQL-like db instead.
Edit: note that there are ways to model relationships in dynamodb but they are not trivial. For some examples see the link below. But as suggested above, first define your access patterns before deciding on your data model.
https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/bp-modeling-nosql-B.html
Related
I am making an application which involves users storing their favorite content series (which each have a unique ID).
The problem is : I want to check if those IDs exists in the database and also to limit the size of this list to a floor (~100 items).
So far, I have tried to implement a RLS policy but checking the content of the posted data is too complex especially for arrays.
I am considering the use of a sort of gateway API that makes a bridge between the user and the database of their profile to insure more checks but before working on that I want to be sure there is no way to implement this by relying on Supabase only.
You can use a database constraint to limit the size of the list to a floor of 100 items. Additionally, you can use a SQL query to check if the IDs exist in the database.
To limit the size of the list, you can use a check constraint on the table that stores the user's favorite content series. The check constraint can be defined to ensure that the size of the array is not greater than 100.
To check if the IDs exist in the database, you can use a SQL query with the "IN" operator. The query can be written to check if each ID in the user's list exists in the database.
These solutions can be implemented using Supabase only, without the need for a gateway API.
I'm developing a web app that allows me to generate product orders in PHP. When I first started, I was thinking only about my product orders, however, I have 3 more sales representatives and I would like for them to use it as well.
The problem I'm currently facing is that whenever I'm looking for product orders (using an ajax), all users are allowed to see all the product orders. I would like that each user can only see **their* product orders, but I'm not sure how the query should be.
What would the query be considering these tables?
Thanks in advance!
UPDATE:
So, thanks to #Nicolas answer, I was able to get only information for a selected vendor. However, the 'nombre_cliente(client name)' from 'clientes' tables is wrong for every row. It is showing only the first row. Other information is correct, except for the name. Here is what the results look like now, and how I'm looping through the data.
results
looping
Thanks in advance to everyone.
From what i understand, You would need to know who's asking the server for every request. There's multiple way to achieve this and we don't have enough informations about your infrastructure to give you a good way to accomplish this. Are you using PHP session, are you using an API with API keys, etc. Either way, To get only the product order for a particular vendor, you would need to execute a SQL that would look like that :
SELECT * FROM `facturas` WHERE `id_vendedor` = 1;
In this example, 1 is the id of the connected user.
This request will filter every order and returns only the one that have been done by the user with the id : 1.
You could also join both tables together and filter by some other property of the user table. Lets say we want to get every order by the user whose name contains "john". we would do a request like that :
SELECT facturas.* FROM `facturas` JOIN `users` ON `facturas`.`id_vendedor` = `users`. `user_id` WHERE `users`.`firstname` LIKE '%john%';
In this case, we are joining both table, mapping every id_vendedor to an user_id in the user table, and filtering by firstname. The like operator can be translate to : 'anything john anything'.
IMPORTANT
If you are doing SQL request in any language, make sure you are binding your parameters
Thanks to #Nicolas help, I was able to fix my problem. The final query is:
SELECT * FROM facturas JOIN clientes ON facturas.id_cliente=clientes.id_cliente where facturas.id_vendedor=$current_user (variable that I used to keep track of who is logged in)
To import my crm data into Google analytics (GA), I linked the UserID of my users with ClientID in GA.
For this, I used the following code from GA documentation:
ga('set', 'userId', '432432');
Over time, the format of the User IDs on my website has changed - instead of the numbers, hashes are now used.
Can I now use the same code above, but only with new identifiers of my users, to send UserIDs то GA without damage current analytics?
In short, can I override the current User IDs in GA so that one user is not identified by the GA system as two different people?
You can't overwrite the historical data already processed by Google Analytics, only those of the current day.
You could apply the new algorithm only to new users of the crm, from a given id on, leaving the same encoding (numbers) for the previous ones (users already processed by Analytics).
If you have a mapping table between the new and old ids there is a solution.
You need to take out the data from GA - historically. (You can use the paid service from Scitylana for this - you get data in BigQuery or in S3)
Then you need a copy of the new_id old_id mappings table in the database where you put the exported data from Scitylana.
Since you can no longer rely on the ga:userType variable (new/returning). You need to create a query that calculates it again using the consolidated new ids.
This can all be set up in a flow that updates nightly.
But you need to analyze via SQL or use a dashboard tool like Power BI, Data Studio, Tableau etc.
Since the data from Scitylana is hit-level you can calculate everything correct, no need to worry about double aggregations etc.
(I work at Scitylana)
We are looking to use Algolia Search for an application. We like the convenience of Algolia but are stuck on one point. We have custom user groups and each user group can only see a subset of the records. When we are pushing records to Algolia all the records show up. How do we pair that with our custom logic of specific users can see specific records and we dont those to show up on the search lists.
The best way to handle this use case is to encode the permission information directly inside your records (like a group or a user). You can for example add a permission array on your record:
"permission": ["group1", "user42"]
You then just need to add this permission attribute in the list of attributes for faceting and apply the restriction in your query via a facetFilters argument.
I would also recommend to use the secured-API key feature that allows to apply this restriction in a secure way even if the query come from a browser or mobile app. A HMAC-SHA 256 signature is computed in your backend between the API key and the restriction to ensure no-one can change this restriction.
Imagine we have two tables, session and movie in postgresql. The table session has a foreignkey to movie. How can i define a relation in movie so that i can ask for movies with filters on session. This table, for example, has a column created and i want to ask for results that has sessions after today with a custom method in Movies.js.
The table session has a foreignkey to movie, then you can define relations on both models(use a custom foreign key if necessary). Then, you can simply query data through the relation you have already defined. just use find, include, scope and where to get the data you want. If you can paste your json files for both models, it will be easy to figure it out.