We’ve got an exciting new feature to announce in 4D v18 and the title may have already given you a hint!
This feature opens new possibilities for client/server work. Rather than being limited to the current database and requiring a permanent network connection, an application in 4D v18 can get data from another, remote 4D database that’s exposed on a 4D server!
A lot of options become available thanks to this feature. For example, you could organize your applications to work offline and only synchronize local data when remote data is reachable. Or you could consider publishing your data on multiple servers and switching from one to the other as necessary. Another option could be splitting your data model across different databases (e.g. local data, international data). What about having your data distributed in different places yet still accessible through a single 4D client code (project methods and form objects)? All of these scenarios are now possible and this blog post tells you how!
Blog post by guest author Cannon Smith, a 4D developer from southern Alberta, Canada:
The introduction of collections and entities has dramatically changed the landscape in 4D, giving developers new ways to map business rules to code. Just recently I refactored several thousand lines of code that were central to the business rules of our application, resulting in a significant speed improvement (5xs faster) which our users are very happy about. This refactoring was largely about moving from old code constructs to objects, collections, and ORDA.
Ever need to analyze the traffic of your ORDA requests between a client and the 4D server? Sometimes it may take a while to receive a response from the server, which can make you wonder if it’s due to network traffic or to an unoptimized request you’ve written! Thankfully, 4D v17 R6 makes it possible to determine the likely reason(s) for this latency with the new ORDA methods available on the ds object. They’re not only debugging functions, they also allow you to optimize your ORDA code with a better understanding of the sent requests.
In a previous blog post, you learned how to build sophisticated and complex search criteria by applying formulas in an ORDA query. To further provide you with complete and powerful development tools, a new ORDA method available: orderByFormula(). With the help of formulas, you can now order an entity selection using complex criteria in a project method or 4D expression.
In 4D v17 R6, ORDA queries are becoming increasingly more powerful and concise. This blog post is for those of you who need more sophisticated search criteria than just a simple syntax like “name = Smith‘”. With this R-release, you can use any project method or 4D expression in the query() member method by using formulas.
What better way to explain this feature than with an example? Let’s dig into the details.
ORDA has its share of features with 4D v17 R5, including various ways to write generic code.
Writing generic code allows you to centralize your code to facilitate updating it. Not only does it enable you to write reusable code that can be used in different use cases, freeing you from having to reinvent the wheel again and again, it also lets you add extra functionalities on top of what you’ve already done.
Using ORDA to access large tables (especially those with relations) in Client/Server mode has been greatly enhanced. With 4D v17 R5, you’ll see 2-3xs improved LAN performance and up to 30xs faster WAN performance. And best of all – there’s no need to change anything in your code, it’s all automatic. Interesting, isn’t it? Well, let’s delve into the details.
“How can I know the dataClass of an entity? I need it to write generic methods“. “I need information about a field in a dataClass: what is its type? Is it indexed? Is it unique?“. These are the kinds of questions we’ve heard you asking on the forum. 4D v17 R5 provides the answers: introducing new ORDA member methods to provide useful information about your database. Keep reading, because you’ll appreciate the benefits of reducing the size of your code and making it reusable and easy to maintain!
The ORDA features keep coming with 4D v17 R5! In a previous blog post, we showed you how to create generic queries with named placeholders for values. This post will focus on how to use placeholders for attribute paths (field names in tables).
By now you’ve surely noticed that ORDA queries are not only light and readable, they also make it easy to navigate through the entire data model using object-oriented concepts! In this blog post, we showed you how to write powerful and easy-to-maintain queries. One of the methods recommended was providing the query and values separately via placeholders. 4D v17 R5 takes placeholders a step further by allowing you to write generic ORDA queries: say hello to named placeholders for values!
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