We're an SME with SAP implemented. We're trying to use the transactional data in SAP to build another system in PHP for our trucking division for graphical reports, etc. This is because we don't have in-house expertise ABAP development and any SAP modifications are expensive.
Presently, I've managed to achieve our objectives with read-only access to our Quality DB2 server and any writes go to another DB2 server. We've found the CPU usage on the SELECT statements to be acceptable and the user is granted access only to specific tables/views.
SAP's Quality DB2 -> PHP -> Different DB2 client
Would like your opinion on whether it is safe to read from production the same way? Implementing all of this again via the RFC connector seems very painful. Master-Slave config is an option for us but again will involve external consultancy.
EDIT
Forgot to mention that our SAP guys don't want to build even reports for another 6-months - they want to leave the system intact. Which is why we're building this in PHP on the top.
If you don't have ABAP expertise, get it - it's not that hard, and you'll get a lot of stuff "for granted" (as in "provided by the platform") that you'll have to implement manually otherwise - like user authentication and authority management and software logistics (moving stuff from the development to the production repository). See these articles for a short (although biased) introduction. If you still need an external PHP application, fine - but you really should give ABAP a try first. For web applications, you might want to look into Web Dynpro ABAP. Using the IGS built'in chart engine with the BusinessGraphics element, you'll get a ton of the most custom chart types for free. You can also integrate PDF forms created with Adobe Livecycle Designer.
Second, while "any SAP modifications are expensive" might be a good approach, what you're suggesting isn't a modification. That's add-on development, and it's neither expensive nor more complex than any other programming language and/or environment out there. If you can't or don't want to implement your own application entirely using the existing infrastructure, at least use a decent interface - web services, RFC, whatever. From an ABAP point of view, RFC is always the easiest option, but you can use SOAP or REST as well, although you'll have to implement the latter manually. It's not that hard either.
NEVER EVER access the SAP database directly. Just don't. You'll have to implement all the constraints like client dependency or checks for validity dates and cancellation flags for yourself - that's hardly less complex than writing a decent interface, and it's prone to break every time the structure is changed. And if at some point you need to read some of the more complex contents like long texts, you're screwed - period. Not to mention that most internal or external auditors (if that happens to be an issue with your company and/or legal requirements) don't like direct database access to a system as critical as this one, which again can cause lots of trouble from people you really don't want to mess with. It's just not worth it.
Related
I am developing a full web application...
I am considering using prismic.io to outsource some web content which I will query through graphQL. But I would store personal information about users in a local instance of mongoDB.
Whats the long term benefit? If I can just store all of the content myself through an instance of mongodb which holds it all for me.
This is mostly my opinion, if you're a developer working alone or just with other developers, and are only looking for a place to store data, then you're probably better off not using a CMS. One of a CMSs main purposes is to extend the ability to significantly modify an application to non-technical individuals. For example, building a website for a local restaurant, and wanting to allow them to change their menu, without you having to build out a UI to enable it. With a CMS they'd be able to easily change the text and other content on their platform, whereas interacting with a mongo backend might be a bit less straightforward for them. For a more industrial example, say you have a marketing team, who need to run A/B tests to determine the optimal content for a site, they can perform their tests, and have their changes reflect into a template you set up, without them (and you if you set it up cleverly) having to write any extra code. There are more advantages and disadvantages to using a CMS, but I think accessibility is the main reason reason to consider one, especially long-term.
I'm admittedly unsure whether this post falls within the scope of acceptable SO questions. If not, please advise whether I might be able to adjust it to fit or if perhaps there might be a more appropriate site for it.
I'm a WinForms guy, but I've got a new project where I'm going to be making web service calls for a Point of Sale system. I've read about how CRUD operations are handled in RESTful environments where GET/PUT/POST/etc represent their respective CRUD counterpart. However I've just started working on a project where I need to submit my requirements to a developer who'll be developing a web api for me to use but he tells me that this isn't how the big boys do it.
Instead of making web requests to create a transaction followed by requests to add items to the transaction in the object based approach I'm accustomed to, I will instead use a service based approach to just make a 'prepare' checkout call in order to see the subtotal, tax, total, etc. for the transaction with the items I currently have on it. Then when I'm ready to actually process the transaction I'll make a call to 'complete' checkout.
I quoted a couple words above because I'm curious whether these are common terms that everyone uses or just ones that he happened to choose to explain the process to me. And my question is, where might I go to get up to speed on the way the 'big boys' like Google and Amazon design their APIs? I'm not the one implementing the API, but there seems to be a little bit of an impedance mismatch in regard to how I'm trying to communicate what I need and the way the developer is expecting to hear my requirements.
Not sure wrt the specifics of your application though your general understanding seems ik. There are always corner cases that test the born though.
I would heed that you listen to your dev team on how things should be imolemented and just provide the "what's" (requirements). They should be trusted to know best practice and your company's own interpretation and standards (right or wrong). If they don't give you your requirement (ease-of-use or can't be easily reusable with expanded requirements) then you can review why with an architect or dev mgr.
However, if you are interested and want to debate and perhaps understand, check out Atlassian's best practice here: https://developer.atlassian.com/plugins/servlet/mobile#content/view/4915226.
FYI: Atlassian make really leading dev tools in use in v.large companies. Note also that this best-practices is as a part of refactoring meaning they've been through the mill and know what worked and what hasn't).
FYI2 (edit): Reading between the lines of your question, I think your dev is basically instructing you specifically on how transactions are managed within ReST. That is, you don't typically begin, add, end. Instead, everything that is transactional is rolled within a transaction wrapper and POSTed to the server as a single transaction.
I'm new to ESBs and wondered if anyone could help me out with the following. I want to build a system which takes data (i.e. RSS feeds, but could be any type of data/news source), pump them into a CMS system, have a content manager approve and, if necessary, tweak this content. Afterwards I would have the content manager select the channels to which he wants to distribute the content to, and then I would like the CMS to distribute this content to the appropriate channels selected by the content manager.
The way I see it is that there would be an ESB-like architecture between the data sources and the CMS, and then once again between the CMS and the channels to which to publish.
Is this a correct method of thinking? Or am I completely wrong in my assumptions?
Also, I wondered if I needed a full-blown ESB setup or could I just do with a Yahoo Pipes setup which transforms all incoming data sources into one feed which I pull into the CMS on one side, and a web service going out from the CMS, which can be called by the separate content channels on the other side?
A piece of advice, don't complicate. You can use Event SOA, but I don't see the benefits you would get from it, because your case scenario is not that complicated, not to say that you only use Event SOA architectures with complicated requirements. You need to think ahead in the future, the SLA's (number of transactions, load balance...) only after that you know the constraints for your architecture, and you can make a decision on whether you need to build your system in a distributed way from the start or have just the base, as service contracts which would allow you to go the distributed way should the need arise. Distributing a system is complicated already, so before you think you need to do that, you need to know the SLA´s for your system, and lay a plan for scalability.
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We have written a software package for a particular niche industry. This package has been pretty successful, to the extent that we have signed up several different clients in the industry, who use us as a hosted solution provider, and many others are knocking on our doors. If we achieve the kind of success that we're aiming for, we will have literally hundreds of clients, each with their own web site hosted on our servers.
Trouble is, each client comes in with their own little customizations and tweaks that they need for their own local circumstances and conditions, often (but not always) based on local state or even county legislation or bureaucracy. So while probably 90-95% of the system is the same across all clients, we're going to have to build and support these little customizations.
Moreover, the system is still very much a work in progress. There are enhancements and bug fixes happening continually on the core system that need to be applied across all clients.
We are writing code in .NET (ASP, C#), MS-SQL 2005 is our DB server, and we're using SourceGear Vault as our source control system. I have worked with branching in Vault before, and it's great if you only need to keep 2 or 3 branches synchronized - but we're looking at maintaining hundreds of branches, which is just unthinkable.
My question is: How do you recommend we manage all this?
I expect answers will be addressing things like object architecture, web server architecture, source control management, developer teams etc. I have a few ideas of my own, but I have no real experience in managing something like this, and I'd really appreciate hearing from people who have done this sort of thing before.
Thanks!
I would recommend against maintaining separate code branches per customer. This is a nightmare to maintain working code against your Core.
I do recommend you do implement the Strategy Pattern and cover your "customer customizations" with automated tests (e.g. Unit & Functional) whenever you are changing your Core.
UPDATE:
I recommend that before you get too many customers, you need to establish a system of creating and updating each of their websites. How involved you get is going to be balanced by your current revenue stream of course, but you should have an end in mind.
For example, when you just signed up Customer X (hopefully all via the web), their website will be created in XX minutes and send the customer an email stating it's ready.
You definitely want to setup a Continuous Integration (CI) environment. TeamCity is a great tool, and free.
With this in place, you'll be able to check your updates in a staging environment and can then apply those patches across your production instances.
Bottom Line: Once you get over a handful of customers, you need to start thinking about automating your operations and your deployment as yet another application to itself.
UPDATE: This post highlights the negative effects of branching per customer.
Our software has very similar requirements and I've picked up a few things over the years.
First of all, such customizations will cost you both in the short and long-term. If you have control over it, place some checks and balances such that sales & marketing do not over-zealously sell customizations.
I agree with the other posters that say NOT to use source control to manage this. It should be built into the project architecture wherever possible. When I first began working for my current employer, source control was being used for this and it quickly became a nightmare.
We use a separate database for each client, mainly because for many of our clients, the law or the client themselves require it due to privacy concerns, etc...
I would say that the business logic differences have probably been the least difficult part of the experience for us (your mileage may vary depending on the nature of the customizations required). For us, most variations in business logic can be broken down into a set of configuration values which we store in an xml file that is modified upon deployment (if machine specific) or stored in a client-specific folder and kept in source control (explained below). The business logic obtains these values at runtime and adjusts its execution appropriately. You can use this in concert with various strategy and factory patterns as well -- config fields can contain names of strategies etc... . Also, unit testing can be used to verify that you haven't broken things for other clients when you make changes. Currently, adding most new clients to the system involves simply mixing/matching the appropriate config values (as far as business logic is concerned).
More of a problem for us is managing the content of the site itself including the pages/style sheets/text strings/images, all of which our clients often want customized. The current approach that I've taken for this is to create a folder tree for each client that mirrors the main site - this tree is rooted at a folder named "custom" that is located in the main site folder and deployed with the site. Content placed in the client-specific set of folders either overrides or merges with the default content (depending on file type). At runtime the correct file is chosen based on the current context (user, language, etc...). The site can be made to serve multiple clients this way. Efficiency may also be a concern - you can use caching, etc... to make it faster (I use a custom VirtualPathProvider). The largest problem we run into is the burden of visually testing all of these pages when we need to make changes. Basically, to be 100% sure you haven't broken something in a client's custom setup when you have changed a shared stylesheet, image, etc... you would have to visually inspect every single page after any significant design change. I've developed some "feel" over time as to what changes can be comfortably made without breaking things, but it's still not a foolproof system by any means.
In my case I also have no control other than offering my opinion over which visual/code customizations are sold so MANY more of them than I would like have been sold and implemented.
This is not something that you want to solve with source control management, but within the architecture of your application.
I would come up with some sort of plugin like architecture. Which plugins to use for which website would then become a configuration issue and not a source control issue.
This allows you to use branches, etc. for the stuff that they are intended for: parallel development of code between (or maybe even over) releases. Each plugin becomes a seperate project (or subproject) within your source code system. This also allows you to combine all plugins and your main application into one visual studio solution to help with dependency analisys etc.
Loosely coupling the various components in your application is the best way to go.
As mention before, source control does not sound like a good solution for your problem. To me it sounds that is better yo have a single code base using a multi-tenant architecture. This way you get a lot of benefits in terms of managing your application, load on the service, scalability, etc.
Our product using this approach and what we have is some (a lot) of core functionality that is the same for all clients, custom modules that are used by one or more clients and at the core a the "customization" is a simple workflow engine that uses different workflows for different clients, so each clients gets the core functionality, its own workflow(s) and some extended set of modules that are either client specific or generalized for more that one client.
Here's something to get you started on multi-tenancy architecture:
Multi-Tenant Data Architecture
SaaS database tenancy patterns
Without more info, such as types of client specific customization, one can only guess how deep or superficial the changes are. Some simple/standard approaches to consider:
If you can keep a central config specifying the uniqueness from client to client
If you can centralize the business rules to one class or group of classes
If you can store the business rules in the database and pull out based on client
If the business rules can all be DB/SQL based (each client having their own DB
Overall hard coding differences based on client name/id is very problematic, keeping different code bases per client is costly (think of the complete testing/retesting time required for the 90% that doesn't change)...I think more info is required to properly answer (give some specifics)
Layer the application. One of those layers contains customizations and should be able to be pulled out at any time without affect on the rest of the system. Application- and DB-level "triggers" (quoted because they may or many not employ actual DB triggers) that call customer-specific code or are parametrized with customer keys) are very helpful.
Core should never be customized, but you must layer it in somewhere, even if it is simplistic web filtering.
What we have is a a core datbase that has the functionality that all clients get. Then each client has a separate database that contains the customizations for that client. This is expensive in terms of maintenance. The other problem is that when two clients ask for a simliar functionality, it is often done differnetly by the two separate teams. There is currently little done to share custiomizations between clients and make common ones become part of the core application. Each client has their own application portal, so we don't have the worry about a change to one client affecting some other client.
Right now we are looking at changing to a process using a rules engine, but there is some concern that the perfomance won't be there for the number of records we need to be able to process. However, in your circumstances, this might be a viable alternative.
I've used some applications that offered the following customizations:
Web pages were configurable - we could drag fields out of view, position them where we wanted with our own name for the field label.
Add our own views or stored procedures and use them in: data grids (along with an update proc) and reports. Each client would need their own database.
Custom mapping of Excel files to import data into system.
Add our own calculated fields.
Ability to run custom scripts on forms during various events.
Identify our own custom fields.
If you clients are larger companies, you're almost going to need your own SDK, API's, etc.
We have a web application which contains a bunch of content that the system operator can change (e.g. news and events). Occasionally we publish new versions of the software. The software is being tagged and stored in subversion. However, I'm a bit torn on how to best version control the content that may be changed independently. What are some mechanisms that people use to make sure that content is stored and versioned in a way that the site can be recreated or at the very least version controlled?
When you identify two set of files which have their own life cycle (software files on one side, "news and events" on the other, you know that:
you can not versionned them together at the same time
you should not put the same label
You need to save the "news and event" files separatly (either in the VCS or in a DB like Ian Jacobs suggests, or in a CMS - Content Management system), and find a way to link the tow together (an id, a timestamp, a meta-label, ...)
Do not forget you are not only talking about two different set of files in term of life cycle, but also about different set of files in term of their very natures:
Consider the terminology introduced in this SO question "Is asset management a superset of source control" by S.Lott
software files: Infrastructure information, that is "representing the processing of the enterprise information asset". Your code is part of that asset and is managed by a VCS (Version Control System), as part of the Configuration management discipline.
"news and events": Enterprise Information, that is data (not processing); this is often split between Content Managers and Relational Databases.
So not everything should end up in Subversion.
Keep everything in the DB, and give every transaction to the DB a timestamp. that way you can keep standard DB backups and load the site content at whatever date you want if the worst happens.
I suppose part of the answer depends on what CMS you're using, and how your web app is designed, but in general, I'd regard data such as news items or events as "content". In other words, it's not part of your application - it's the data which your application processes.
Of course, there will be versioning issues between your CMS code and your application code. You could manage this by defining the interface between the two. Personally, I'd publish the data to the web app as XML, which gives you the possibility of using XML schema to define exactly what the CMS is required to produce, and what the web app should expect to process.
This ought to mean that most changes in the web app can be made without a corresponding alteration in the rendering of the data. When functionality changes require this, you can create a new version of the schema and continue to make progress. In this scenario, I'd check the schema in with the web app code, but YMMV.
It isn't easy, and it gets more complicated again if you need additional data fields in your CMS. Expect to plan for a fairly complex release process (also depending on how complex your Dev-Test-Acceptance-Production scenario is.)
If you aren't using a CMS, then you should consider it. (Of course, if the operation is very small, it may still fall into the category where doing it by hand is acceptable.) Simply putting raw data into a versioning system doesn't solve the problem - you need to be able to control the format in which your data is published to the web app. Almost certainly this format should be something intended for consumption by software, and therefore not usually suitable for hand-editing by the kind of people who write news items or events.