Connecting Power Apps Model-Driven Apps to SQL Server tables - sql-server

Trying to figure out the best way of managing data stored in an on-premise SQL Server database, for a Power Automate Model-Driven App. For Canvas Apps, typically I use a connector to either access the tables directly, or to access the data via a Power Automate flow.
From my research, it seems like I have two options:
Create Dataverse tables which represent all of my SQL Server tables, and use an ETL tool to keep those tables in sync.
Use a Virtual Table to connect "directly" to the SQL Server tables
Neither of those options really seem great, though. The entire premise of the Power Platform is for a relatively low-code experience, and both of those two options require quite a bit of coding. The ETL option, for example, requires me to write ETL operations for every table that I want to manage, along with dealing with any number of concurrency issues that may arise. The Virtual Table, on the other hand, seems on the surface like it'd be a better approach, but to actually implement a Virtual Table for an SQL Server table, I need to write a custom connector, and I need to leverage the old D365 UI to manage it.
The "best" approach I've seen so far is explored a bit by Juuka Niiranen in this blog post, however, a year later, and the approach he wrote about is still in preview: https://jukkaniiranen.com/2021/06/virtual-dataverse-tables-with-no-code-via-connectors/ and https://learn.microsoft.com/en-us/power-apps/maker/data-platform/create-virtual-tables-using-connectors?tabs=sql
Does anyone have any other suggestions? Is that above connector approach the recommended one, despite still being in preview?

Related

Copy dbo to a new Schema in MSSQL

I got a database in SQL where everything is in the dbo schema. Now we want to copy that schema to have two schemas in the same database with the exact same content. Is there any easy way to do this in an Azure Database?
(We want to separate our Development and UAT but still only use one database)
While the other answer posted here, using the SSIS to transfer the SQL objects, will work, I feel compelled to point out that your approach raises a lot of other concerns.
Using a single database for two environments is not a good practice. The first big issue with is how do you handle deployments? Let's say UAT is in the uat schema and development is in development is the dev schema. You make a change to the Customers table, how do you deploy the table change to both schemas? If you use SSIS, you will need an on-premise SSIS server that handles copying the changes to the various shcemas in the target database. This will create a large maintenance headache and likely lead to important changes being wiped out.
Another issue this results in how does your application target a specific schema? You can have a login defaulted to a specific schema when it runs, but many ORM tools will want to the schema ahead of time. This will force to write the code in way that could potentially force to deploy different code to different environments. This opens up the possibility that parts of the code won't get test until production.
The last concern I have is with this approach, versioning your database becomes difficult and many of the tools that are out there, won't support what you are doing. This means you will likely be creating custom processes and tools to deploy a database instead of leveraging tools built by vendors like Microsoft or Red Gate. This puts you in a position where you need to support not only the application you make for your customers, but also an application to do your job (basically doubling your work).
My suggestion is think about the need to run two environments in a single database. I'm assuming this is likely due to cost, in which case you might find this to be false. Azure has many pricing tiers to support customers with various budgets. Depending on your application workload for both environments, you will likely find you need a large DTU database to support both. You might find that by having two databases, you can leverage smaller DTUs tiers which may end up being cheaper.
Please use the CopySchema option of the Transfer SQL Server Objects Task in SSIS as explained here.

C# How to Synch Data Between Database Instances Over the Internet

We have an application that requires our customers to have a SQL server instance on site. At their request, the application needs to synchronize the data in their database with a copy in our datacenter.
We're using .Net 3.5 SP1. We need to synchronize the data exactly, including IDENTITY columns.
We'd prefer to use something like LINQ to SQL that would let us make some simple select and insert/update calls against mapped entities. However, the IDENTITY columns seem to be a problem with LINQ and similar approaches.
We can do this all with built-up SQL statements and turn IDENTITY INSERT on / off as needed, but I'd prefer a more elegant solution.
Thanks!
** Edit - We DO need to write our own solution, and we do need to use .Net 3.5 SP1 to do it. I won't spend your time explaining all the reasons why, but please limit suggestions to options within the .Net playground.
Microsoft Sync Framework can be your solution. This is framework description from Microsoft:
Microsoft Sync Framework is a data synchronization platform from Microsoft that can be used to synchronize data across multiple data stores. Sync Framework includes a transport-agnostic architecture, into which data store-specific synchronization providers, modelled on the ADO.NET data provider API, can be plugged in.
Sync Framework is a comprehensive data synchronization solution that enables developers to build solutions that support synchronization of any database, on any data protocol over any network topology. msdn.microsoft.com
For your convinience providing link to good tutorial on the subject
If it is just a couple of tables that need to be synchronized and there is not a lot of data in the tables (now and future) you could develop some sort of bulk copy from your servers and bulk insert routine on the customer's server.
Since you said you can't use SQL Server replication services or SSIS, then perhaps a backup/restore procedure could be written. You could take a scheduled backup of your database and make it available to calling applications which could then copy the backup, restore it to another instance on the customers server, then pull all data you need via any number of methods and it would exist locally on the customers servers.
Beyond that, I think you may be asking for a maintenance and synchronization nightmare if you can't base your solution on tools that are made to do this sort of thing.

what is recommended for a wpf app, sql database or xml

I want to build a wpf app (with mvvm dp) and I need to manage a list of customers (200 customers maximum)
What is the recommended way to handle this? sql (mySql, sqlServer) or other way (xml, excel, access)?
I can see advantage in xml because its not required addition installation
If you've got multiple users on different machines, and those machines have a persistent, shared network connection (they're on the same network, for instance), then you should prefer to use a central database, like (as you mention) SQL Server or MySQL. The latter is free, and the former is available in a free edition (Express) for light workloads.
If you don't need to share data between the different users of your application (you don't mind if their customer data get out of sync), then look at lightweight, embedded databases, like SQLite or SQL Server Compact Edition. Very simple and easy to set up and maintain, but the data stays present on a single machine.
You could build an infrastructure around manual synchronization between the different machines, sort of like how iTunes synchronizes data between your computer and iPhone whenever you plug the latter in, but trust me, that's a lot of work that's best avoided if possible. Databases have a lot of built-in multiple-users-doing-stuff-at-the-same-time logic that you want to leverage if at all possible.
If the only thing you need to persist is a list of 200the items and you don't see there as being any other persistent data requirements in the future, I would say that a flat file is plenty. However, this also depends on how often that small data will be retrieved.
I am a huge proponent of SQL Server, and Express is free. But you don't want to overengineer the problem. Unless I misunderstood your question, that is my evaluation.

LINQ with existing databases and unknown schema

I'm working on a database heavy project, where the Microsoft SQL databases are very mature (16 or more years-old mature), and an old product uses VB6 and ADO to generate sql which interacts with the database. I've been given the task of porting/re-writing the ancient version with a new .NET version.
I'd love to use LINQ-to-* to ensure easy maintainability, but having tried for the last several weeks I feel like LINQ-to-SQL isn't flexible enough, LINQ-to-Entities has too much overhead, and LINQ-to-Datasets is pointless since I would be just as happy using Ado.Net.
The program operates on two databases at once: one is a database with a very consistent schema containing meta-data, and the other a database which has a varying schema, is tightly coupled to the meta-database, and dictates what information from the meta-database you are interested in at any given time. Furthermore, I need non-LINQ information from both databases (such as system-stored procedures, and system-tables).
Is there any way to use LINQ intelligently here? I'd love the static typing, but if I can't have it I don't want to force my square app into a round framework.
Just an FYI, you can get access system tables (and sys stored procs too?) using LINQ. Here is how:
Create a connection to the server you want.
Right-click the server and choose Change View > Object Type.
You should now see System Tables and User Tables. You should see sysjobs there, and you can easily drag it onto a .dbml surface.
Above was stolen from this post.
The best answer seems to be to use ADO.NET completely. I have the option of using Linq-to-Sql over the metabase and ADO.NET for any other database access, but that would make the code feel too inconsistent for me.

MS Access Application - Convert data storage from Access to SQL Server

Bear in mind here, I am not an Access guru. I am proficient with SQL Server and .Net framework. Here is my situation:
A very large MS Access 2007 application was built for my company by a contractor.
The application has been split into two tiers BY ACCESS; there is a front end portion that holds all of the Ms Access forms, and then on the back end part, which are access tables, queries, etc., that is stored on a computer on the network.
Well, of course, there is a need to convert the data storage portion to SQL Server 2005 while keeping all of these GUI forms which were built in Ms Access. This is where I come in.
I have read a little, and have found that you can link the forms or maybe even the access tables to SQL Server tables, but I am still very unsure on what exactly can be done and how to do it.
Has anyone done this? Please comment on any capabilities, limitations, considerations about such an undertaking. Thanks!
Do not use the upsizing wizard from Access:
First, it won't work with SQL Server 2008.
Second, there is a much better tool for the job:
SSMA, the SQL Server Migration Assistant for Access which is provided for free by Microsoft.
It will do a lot for you:
move your data from Access to SQL Server
automatically link the tables back into Access
give you lots of information about potential issues due to differences in the two databases
keeps track of the changes so you can keep the two synchronised over time until your migration is complete.
I wrote a blog entry about it recently.
You have a couple of options, the upsizing wizard does a decent(ish) job of moving structure and data from access to Sql. You can then setup linked tables so your application 'should' work pretty much as it does now. Unfortunately the Sql dialect used by Access is different from Sql Server, so if there are any 'raw sql' statements in the code they may need to be changed.
As you've linked to tables though all the other features of Access, the QBE, forms and so on should work as expected. That's the simplest and probably best approach.
Another way of approaching the issue would be to migrate the data as above, and then rather than using linked tables, make use of ADO from within access. That approach is kind of famaliar if you're used to other languages/dev environments, but it's the wrong approach. Access comes with loads of built in stuff that makes working with data really easy, if you go back to use ADO/Sql you then lose many of those benefits.
I suggest start on a small part of the application - non essential data, and migrate a few tables and see how it goes. Of course you back everything up first.
Good luck
Others have suggested upsizing the Jet back end to SQL Server and linking via ODBC. In an ideal world, the app will work beautifully without needing to change anything.
In the real world, you'll find that some of your front-end objects that were engineered to be efficient and fast with a Jet back end don't actually work very well with a server database. Sometimes Jet guesses wrong and sends something really inefficient to the server. This is particular the case with mass updates of records -- in order not to hog server resources (a good thing), Jet will send a single UPDATE statement for each record (which is a bad thing for your app, since it's much, much slower than a single UPDATE statement).
What you have to do is evaluate everything in your app after you've upsized it and where there are performance problems, move some of the logic to the server. This means you may create a few server-side views, or you may use passthrough queries (to hand off the whole SQL statement to SQL Server and not letting Jet worry about it), or you may need to create stored procedures on the server (especially for update operations).
But in general, it's actually quite safe to assume that most of it will work fine without change. It likely won't be as fast as the old Access/Jet app, but that's where you can use SQL Profiler to figure out what the holdup is and re-architect things to be more efficient with the SQL Server back end.
If the Access app was already efficiently designed (e.g., forms are never bound to full tables, but instead to recordsources with restrictive WHERE clauses returning only 1 or a few records), then it will likely work pretty well. On the other hand, if it uses a lot of the bad practices seen in the Access sample databases and templates, you could run into huge problems.
It's my opinion that every Access/Jet app should be designed from the beginning with the idea that someday it will be upsized to use a server back end. This means that the Access/Jet app will actually be quite efficient and speedy, but also that when you do upsize, it will cause a minimum of pain.
This is your lowest-cost option. You're going to want to set up an ODBC connection for your Access clients pointing to your SQL Server. You can then use the (I think) "Import" option to "link" a table to the SQL Server via the ODBC source. Migrate your data from the Access tables to SQL Server, and you have your data on SQL Server in a form you can manage and back up. Important, queries can then be written on SQL Server as views and presented to the Access db as linked tables as well.
Linked Access tables work fine but I've only used them with ODBC and other databases (Firebird, MySQL, Sqlite3). Information on primary or foreign keys wasn't passing through. There were also problems with datatype interpretation: a date in MySQL is not the same thing as in Access VBA. I guess these problems aren't nearly as bad when using SQL Server.
Important Point: If you link the tables in Access to SQL Server, then EVERY table must have a Primary Key defined (Contractor? Access? Experience says that probably some tables don't have PKs). If a PK is not defined, then the Access forms will not be able to update and insert rows, rendering the tables effectively read-only.
Take a look at this Access to SQL Server migration tool. It might be one of the few, if not the ONLY, true peer-to-peer or server-to-server migration tools running as a pure Web Application. It uses mostly ASP 3.0, XML, the File System Object, the Data Dictionary Object, ADO, ADO Extensions (ADOX), the Dictionary Scripting Objects and a few other neat Microsoft techniques and technologies. If you have the Source Access Table on one server and the destination SQL Server on another server or even the same server and you want to run this as a Web Internet solution this is the product for you. This example discusses the VPASP Shopping Cart, but it will work for ANY version of Access and for ANY version of SQL Server from SQL 2000 to SQL 2008.
I am finishing up development for a generic Database Upgrade Conversion process involving the automated conversion of Access Table, View and Index Structures in a VPASP Shopping or any other Access System to their SQL Server 2005/2008 equivalents. It runs right from your server without the need for any outside assistance from external staff or consultants.
After creating a clone of your Access tables, indexes and views in SQL Server this data migration routine will selectively migrate all the data from your Access tables into your new SQL Server 2005/2008 tables without having to give out either your actual Access Database or the Table Contents or your passwords to anyone.
Here is the Reverse Engineering part of the process running against a system with almost 200 tables and almost 300 indexes and Views which is being done as a system acceptance test. Still a work in progress, but the core pieces are in place.
http://www.21stcenturyecommerce.com/SQLDDL/ViewDBTables.asp
I do the automated reverse engineering of the Access Table DDLs (Data Definition Language) and convert them into SQL equivalent DDL Statements, because table structures and even extra tables might be slightly different for every VPASP customer and for every version of VP-ASP out there.
I am finishing the actual data conversion routine which would migrate the data from Access to SQL Server after these new SQL Tables have been created including any views or indexes. It is written entirely in ASP, with VB Scripting, the File System Object (FSO), the Dictionary Object, XML, DHTML, JavaScript right now and runs pretty quickly as you will see against a SQL Server 2008 Database just for the sake of an example.
It takes perhaps 15-20 seconds to reverse engineer almost 500 different database objects. There might be a total of over 2,000 columns involved in this example for the 170 tables and 270 indexes involved.
I have even come up with a way for you to run both VPASP systems in parallel using 2 different database connection files on the same server just to be sure that orders entered on the Access System and the SQL Server system produce the same results before actual cutover to production.
John (a/k/a The SQL Dude)
sales#designersyles.biz
(This is a VP-ASP Demo Site)
Here is a technique I've heard one developer speak on. This is if you really want something like a Client-Server application.
Create .mdb/.mde frontend files distributed to each user (You'll see why).
For every table they need to perform an CRUD, have a local copy in the file in #1.
The forms stay linked to the local tables.
Write VBA code to handle the CRUD from the local tables to the SQL Server database.
Reports can be based off of temp tables created from the SQL Server (Won't be able to create temp tables in mde file I don't think).
Once you decide how you want to do this with a single form, it is not too difficult to apply the same technique to the rest. The nice thing about working with the form on a local table is you can keep a lot of the existing functionality as the existing application (Which is why they used and continue to use Access I hope). You just need to address getting data back and forth to the SQL Server.
You can continue to have linked tables, and then gradually phase them out with this technique as time and performance needs dictate.
Since each user has their own local file, they can work on their local copy of the data. Only the minimum required to do their task should ever be copied locally. Example: if they are updating a single record, the table would only have that record. When a user adds a new record, you would notice that the ID field for the record is Null, so an insert statement is needed.
I guess the local table acts like a dataset in .NET? I'm sure in some way this is an imperfect analogy.

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