I have a requirement in which I have create customer into external system, When i create it in AX. first solution which came to my mind, was too consume the external party web service into AX.
but how will it implement distributed transactions ??
Your integration options are many, but I would not recommend inserting directly into SQL. That is a really bad solution. The obvious reason is the fact that having an insertion of records done outside of the AOT breaks the business logic persisted in the AOT. The database is only meant for persisting data and optimization of read and write of data. The business logic in the AOT is responsible for hold all the logic when creating and updating records.
In my opinion the only choice you have is through x++ code. Standard AX has a special class for this purpose, "AxCustTable". You want to use this class to make sure your customer data is in best shape throughout the life if your integration.
As for transportation of data between the systems, your choices are many:
* Textfiles
* Xml files
* webservices
* read data from a different sql database
* etc
Just make sure that when you write data to your CustTable all the current and future business logic is still in effect. Insering data directly into the CustTable on the database level would efficently break that dependency.
Good luck!
You didn't write all the requirements fully. So this is what I'm thinking.
I would use Message Queue for this. It can happen that the external system cannot save the customer at the time when the user creates the customer in AX (down time or something else). I wouldn't let the external system stand too much in the way of my application...
How will it implement distributed transactions?
It will not!
But does it matter?
Customer data changes rarely and rarely need transactional scope.
You can create Linked Server and use distributed transactions with direct SQL (class ODBCConnection)
Related
I have a database question. I am developing an application where users sends some request and gets an answer from a vendor. I have a server receiving the request (through a rest call or a running web service, haven't decided which yet).
Whenever a new request comes in it should be logged in a database and when the vendor responds the record should be updated indicating whether it was accepted or not and stuff like that. The only reason for this storage of transactions is for reporting and logging purposes. So now that I have stated my requirement I need help from someone with more expertise in this.
What I've come up with so far is that it would be best to use a structured database since all records will have one type and the same information, so there's no need to waste space using a semi-structured database with each record containing both structure and information.
But I don't know if there are any databases that are particularly good for this kind of "create/update operations only" ?? As I said I only need to read the data perhaps once a month or so.
Any inputs are appreciated!
You can use any open source database like postgreSql as you are mostly going to do inserts and not much other features needed. My suggestion will try to put logging process in separate threads rather than the one you are using for processing to have better performance for your api calls.
I'm developing a application with a lot of create/update queries and currently using Neo4j.
It's fast and really good with j2E and php. NoSQL is really fast to learn with it, and the web interface is really user friendly :)
I'm currently working in a Silverlight / MS SQL project where the Entity Framework has not been implemented and I would like to know what's the best practice to deal with calculated fields in this particular situation.
Considering that some external system might also consume my data directly in the DB or thru a web service, here's the 3 options I can see right now.
1) Force any external system to consume data thru a web service and create all the calculated fields in the objects only.
2) Create the calculated fields in a DB view and resync your object with the server each time a value needs to be calculated.
3) Replicate the calculation rules in the object and the database view.
Any other suggestions would also be welcomed.
I would recommend to follow two principles: data decoupling and minimum functionality duplication. Both would suggest to put your calculations in one place only, and serve them already calculated. So I would implement the calculations in the DB, and serve them via a web service.
However, you have to consider your particular case. For example, if the calculations are VERY heavy, you could delegate them to the client to spare server resources. This could even be the reason you are using Silverlight. I am in a similar situation on a project, and I found that the best compromise is to push raw data to the client and have it do the heavy computations.
Having a best practice or approach for this kind of problem is difficult as circumstances change what was formerly a good approach might start to seem less useful. That said where possible I would do anything data related at the DB level including calculated fields. This way you know no matter where you are looking at the data from you will see the same results. So your web service, SQL reporting and anything else that needs to look at or receive data will see the same result.
I am using Action Filter Attributes for loging user activity on certain action which has SQL database interaction. Similarly I can log the activity in the SQL tables using triggers on tables during each activity on the tables. I would like to know which of the above two methods is a best practice ( perfomance wise )
I think that the actionfilter is certainly the cleanest and best practice appraoch since it is in the application layer. Part of the benefit of being there is its managed code and if something breaks you can easily locate the problem. There is also the benefit that all your code is in one spot too.
Database triggers are a big no no in many companies since they have a habit of causing infinite loop well an unknowing programmer creates some logic that steps on the trigger over and over again causing the database to fail. Some companies do allow triggers but very well documented and very lightly used. Hope this helps.
Performance of logging depends greatly on the system architecture. If you have 3 load balanced web servers hitting one main database, triggers would have to handle all the load while Action Filters would split the load in three. In that scenario, Action Filters would be better.
In terms of best practices, I wouldn't use either of those approaches. I would set up Transactional Replication to another SQL server. This approach would run without impacting performance at all. The transaction log is already being generated and replication would just spin up a separate process that's reading that log.
We have a Data Access service in our SOA WCF system. This service is responsible for doing CRUD (create, update, delete) operations on "system wide" database tables, and is also the source of this data for queries. Any other service in the system wanting to access the tables under the contol of the DAS have to go to the DAS to get it or modify it. We use Entity Framework and built our own POCO state tracking system for this DAS.
We have other tables in our database that belong to single services and store data only for their own use, ie state information they can access if they crash and resume or recording of business information. We have a rule any one table cannot be accessed by more than one service: so data needed by multiple services ends up in the DAS.
Truth is I have never really understood why a Data Access Service is a good idea as opposed to just accessing tables directly. It seems to be to be slower, our DAS is not transactional as it cannot send back a POCO graph for database update (only single POCOS at a time) and we have issues also where the DAS is actually a client to another service which needs data from it...circular dependancy.
Why bother with a DAS? Why is a DAS so important when it comes to SOA? What am I missing here? Single point of control?
Is it also an SOA design flaw that not all tables are part of a DAS and that some services have their own "private" tables?
Any discussion about this welcome.
You're correct in thinking that this is the proper way to do things, and you're also correct that it slows things down and can occasionally be cumbersome. SOA necessarily trades off some efficiency in exchange for ensuring single points of control for all data associated with a service. In fact, even the idea of having a "common DAS" service is slightly smelly in some SOA circles.
By centralizing all CRUD operations to one service in an SOA application, you can ensure data integrity and that business rules are being acted upon properly. To give an example, think of an entity you'd like to store that has some business rules associated with it that are difficult to approach from a pure SQL perspective - for example, let's say a table that stores file references, and create / update services that ensure that these files exist.
With SOA and a single access point to those tables, you can code the logic into the create / update methods and be reasonably assured that the data you're recieving from the service is valid - i.e. the files referenced exist. If anyone was capable of writing to these tables or retrieving data from them, no such assurance would exist - even if you're calling the service yourself, you don't know what other programmers, through malice or just plan forgetfulness, forgot to implement that critical business rule. This leads to defensive programming where every bit of client code is ensuring business logic independently, and ultimately a tangled mess of business logic scattered throughout your application.
Another benefit is scalability and maintanability. Let's say one of your services is accessing a huge chunk of data. With SOA, everything is "black-boxed" so that your client code doesn't have much knowledge of how the data is ultimately obtained. You could change your RDBMS, partition tables, or implement caching, and make that all invisible to the client code calling it - ensuring your painful updates only need to be made in one place. With database code scattered throughout your app, this sort of upgrade becomes extremely painful.
We're building a Silverlight application which will be offered as SaaS. The end product is a Silverlight client that connects to a WCF service. As the number of clients is potentially large, updating needs to be easy, preferably so that all instances can be updated in one go.
Not having implemented multi tenancy before, I'm looking for opinions on how to achieve
Easy upgrades
Data security
Scalability
Three different models to consider are listed on msdn
Separate databases. This is not easy to maintain as all schema changes will have to be applied to each customer's database individually. Are there other drawbacks? A pro is data separation and security. This also allows for slight modifications per customer (which might be more hassle than it's worth!)
Shared Database, Separate Schemas. A TenantID column is added to each table. Ensuring that each customer gets the correct data is potentially dangerous. Easy to maintain and scales well (?).
Shared Database, Separate Schemas. Similar to the first model, but each customer has its own set of tables in the database. Hard to restore backups for a single customer. Maintainability otherwise similar to model 1 (?).
Any recommendations on articles on the subject? Has anybody explored something similar with a Silverlight SaaS app? What do I need to consider on the client side?
Depends on the type of application and scale of data. Each one has downfalls.
1a) Separate databases + single instance of WCF/client. Keeping everything in sync will be a challenge. How do you upgrade X number of DB servers at the same time, what if one fails and is now out of sync and not compatible with the client/WCF layer?
1b) "Silos", separate DB/WCF/Client for each customer. You don't have the sync issue but you do have the overhead of managing many different instances of each layer. Also you will have to look at SQL licensing, I can't remember if separate instances of SQL are licensed separately ($$$). Even if you can install as many instances as you want, the overhead of multiple instances will not be trivial after a certain point.
3) Basically same issues as 1a/b except for licensing.
2) Best upgrade/management scenario. You are right that maintaining data isolation is a huge concern (1a technically shares this issue at a higher level). The other issue is if your application is data intensive you have to worry about data scalability. For example if every customer is expected to have tens/hundreds millions rows of data. Then you will start to run into issues and query performance for individual customers due to total customer base volumes. Clients are more forgiving for slowdowns caused by their own data volume. Being told its slow because the other 99 clients data is large is generally a no-go.
Unless you know for a fact you will be dealing with huge data volumes from the start I would probably go with #2 for now, and begin looking at clustering or moving to 1a/b setup if needed in the future.
We also have a SaaS product and we use solution #2 (Shared DB/Shared Schema with TenandId). Some things to consider for Share DB / Same schema for all:
As mention above, high volume of data for one tenant may affect performance of the other tenants if you're not careful; for starters index your tables properly/carefully and never ever do queries that force a table scan. Monitor query performance and at least plan/design to be able to partition your DB later on based some criteria that makes sense for your domain.
Data separation is very very important, you don't want to end up showing a piece of data to some tenant that belongs to other tenant. every query must have a WHERE TenandId = ... in it and you should be able to verify/enforce this during dev.
Extensibility of the schema is something that solutions 1 and 3 may give you, but you can go around it by designing a way to extend the fields that are associated with the documents/tables in your domain that make sense (ie. Metadata for tables as the msdn article mentions)
What about solutions that provide an out of the box architecture like Apprenda's SaaSGrid? They let you make database decisions at deploy and maintenance time and not at design time. It seems they actively transform and manage the data layer, as well as provide an upgrade engine.
I've similar case, but my solution is take both advantage.
Where data and how data being placed is the question from tenant. Being a tenant of course I don't want my data to be shared, I want my data isolated, secure and I can get at anytime I want.
Certain data it possibly share eg: company list. So database should be global and tenant database, just make sure to locked in operation tenant database schema, and procedure to update all tenant database at once.
Anyway SaaS model everything delivered as server / web service, so no matter where the database should come to client as service, then only render by client GUI.
Thanks
Existing answers are good. You should look deeply into the issue of upgrading and managing multiple databases. Without knowing the specific app, it might turn out easier to have multiple databases and not have to pay the extra cost of tracking the TenantID. This might not end up being the right decision, but you should certainly be wary of the dev cost of data sharing.