I am new to microservices, and I need to create a "Student" service, which will get, save and also adds via a webhook from another thirdparty application
However, one of the fields i need to save is "Subject"
Normally, in SQL i would have a subject table, with things like
ID | Subject
1, Maths
2, English
3, Software
which i can use to populate drop down boxes, and in my Student table, i could have "SubjectId" field
However, if using a microservice... how would i setup my student microservice database so its independent?
then, what if I have a "CollegeCourse" service, which also needs the Subject type?
Should they both have there own 2nd database table, but doesnt that run the risk of a miss match... or maybe a nugGet package and just hardcode some enums which i can share between microservices?
Thank you
I can seem to find any suggestions or answers anywhere for this, but,
Related
I'm trying to write microservices in Java. I've implemented GraphQL endpoints using graphql-spring-boot-starter.
Now I have a problem how to make it efficient.
Datamodel is like a tree and I need to query for data from multiple services at once. The problem is how to filter for a member of collection, something like CONTAINS in database, but data is not in separate table, but separate microservice. Maybe the problem is that domain is not correctly splitted between services?
Let's make an example: I have 3 microservices: users, libriaries, books. Every library have collection of users and books (just list of identifiers, like foreign keys). Every book has a name and genre. Every library have lists of books borrowed by user (identifiers too).
Question 1 - should library hosts list of books and users (just identifiers, like foreign keys)? Is it correct approach?
Question 2 - I want to find libraries in which specified users (by surname) have borrowed books of specified genre. Going from top I need to first find libraries containing users. Not easy, as we have names in different service. We need to query first for users, gathers their identifiers, and now we are able to query for libraries. But it isn't all. Now we need to find books for every user and check genres - in different service. And it's not all. I want to have everything presented in nice way, so whole output should be sorted and paged. It force me to collect all data from all services, then page and sort it, which of course will not be efficient.
Please don't concentrate on this example, I'm looking how to solve general approach, not this one example. I've tried to use Datafetchers but it's troublesome and there are not good examples of calling Graphql-to-GraphQL. Most examples covers calling REST endpoints etc.
I want to create a membership based site in Umbraco 7, following the umbraco.tv videos and reading through the docs have got me quite far.
My members will have custom properties, firstname, lastname, favourite colours, hats owned etc. I have been adding each of these as custom properties and then assigning them to the tab I want. This works fine and I can then access them from code using:
Members.GetCurrentMember().GetProperty("lastname").Value.ToString();
When I looked in my database I noticed that each of these custom properties is a row in the cmsPropertyData table, linked to the cmsMember table by the nodeId column. Is there a way I can set all of this information to store in it's own table?
Ideally, I want each Member to have a one to many relationship with favourite colours, as well as one to many relationships with other tables; each member might have 100 hats for example. What is the best way for me to set this up? Shall I create custom tables in my Umbraco database for HatsOwned and FavouriteColours, then assign each Member a unique ID so I can set my foreign keys up correctly? That way I would only need to store the Members Unique Id in the cmsPropertyTable. Is there a better way to let Umbraco deal with it? Would I have difficulty retrieving Members using either the Umbraco orm, or EF?
Any help or pointers greatly appreciated!
I would store all data in the PROFILE of the member, in the umbraco membership. E.g. timezone, hair color, ... This makes sense for other developers to find back the data.
For all other data, you have a few options:
Relationships
If you want to link nodes to members, or nodes to nodes, or... Relations link 2 umbraco entities and can be one way or two way. If you have a color node, you can link all members to this node. Just create a "favoriteColor" relationship on the developer section, linking up nodes to members. Do some programming and you are done. Don't forget that a relation is a database record linking 2 umbraco entities. So think of some caching if you use this in your front end to take off some database load. Read more on the Relationship Api in the umbraco documentation.
Content
It's pretty easy to create new nodes using code to store e.g. comments on an article. Because you are republishing the xml cache every time you create (and publish) a node, don't use content nodes for stroring your data if you have a lot of updates.
External data
It is perfectly legit to store data outside of umbraco. Just create your own tables (or content to any service you created). You could use every ORM you want to, but I would recommend PetaPoco. The reason is obvious. Umbraco uses it also. And it will make you a better Umbraco developer. There is a detailed post on stackoverflow on how to work with external data in umbraco.
I'm about to embark on a project where a user will be able to create their own custom fields. MY QUESTION - what's the best approach for something like this?
Use case: we have medical records with attributes like first_name, last_name etc... However we also want a user to be able to log into their account and create custom fields. For instance they may want to create a field called 'second_phone' etc... They will then map their CRM to their fields within this app so they can import their data.
I'm thinking on creating tables like 'field_sets (has_many fields)', 'fields', 'field_values' etc...
This seems like it would be somewhat common hence why I thought I would first ask for opinions and/or existing examples.
This is where some modern schemaless databases can help you. My favourite is MongoDB. In short: you take whatever data you have and stuff a document with it. No hard thinking required.
If, however, you are in relational land, EAV is one of classic approaches.
I have also seen people do these things:
predefine some "optional" fields in the schema and use them if necessary.
serialize this optional data to string (using JSON, for example) and write it to text blob.
can someone help me understand the identity property on an entity attribute? Im thinking of the identity property as a table "key" as in a Relational Database, but I'm guessing this is not it.
Im using core data and in my entities I have not defined any "Key" columns, and all is working fine.
But now that I have added sync services to my app, Im not sure how to use this sync attribute. My app is a task management planner, so I have an entity called task. I have an attribute called "name" , "due date" and other optional attributes. If I have 2 tasks with the same name, I want them both sync, so Im guessing the identity property wont do me good if I set it on the attribute "name". Right now I have not used it, and sync services is working fine...
So my question is, in what other scenarios should I use the identity property?
Are you using the standard definition of a task entity from Sync Services? Apple defined one fairly well:
http://developer.apple.com/library/mac/#documentation/AppleApplications/Reference/SyncServicesSchemaRef/Articles/Calendars.html
If so, there are three identity properties (summary, record id and calendar).
If you're defining your own entity (not sharing with the system entity) you can make additional attributes identity properties - I'd probably go with "name" and "due date" for sure; you could also add in a "created date" to ensure that you are able to truly create a unique value to compare records using.
In my experience, however, Sync Services has done a good job keeping track of tasks with the identity properties of the system's schema - I can't remember the last time I saw duplicate tasks coming through my own or user's data.
Tell me more about why you might not want to use the system schema but instead roll your own - I can think of pros and cons to each.
I've made a custom entity that will work as an data modification audit (any entity modified will trigger creating an instance of this entity). So far I have the plugin working fine (tracking old and new versions of properties changed).
I'd like to also keep track of what entity this is related to. At first I added a N:1 from DataHistory to Task (eg.) and I can indeed link back to the original task (via a "new_tasksid" attribute I added to DataHistory).
The problem is every entity I want to log will need a separate attribute id (and an additional entry in the form!)
Looking at how phone, task, etc utilize a "regardingobjectid", this is what I should do. Unfortunately, when I try to add a "dataobjectid" and map it to eg Task and PhoneCall, it complains (on the second save), that the reference needs to be unique. How does the CRM get around this and can I emulate it?
You could create your generic "dataobjectid" field, but make it a text field and store the guid of the object there. You would lose the native grids for looking at the audit records, and you wouldn't be able to join these entities through advanced find, fetch or query expressions, but if that's not important, then you can whip up an ASPX page that displays the audit logs for that record in whatever format you choose and avoid making new relationships for every entity you want to audit.
CRM has a special lookup type that can lookup to many entity types. That functionality isn't available to us customizers, unfortunately. Your best bet is to add each relationship that could be regarding and hide the lookups that aren't in use for this particular entity.