Using Entity Framework with Informix - entity-framework

I've been trying for quite some time to use Entity Framework with our IBM Informix databases. Hours of searching has pointed me towards installing the IBM .NET Data Server Provider, which I have installed, however when I attempt to add a new Entity Model to my project I only have the Microsoft SQL Server Data Providers listed. Am I missing a step? Is this even possible?

I am not an expert on Windows or .NET; treat any comments I make with due caution.
Installing the .NET Data Server Provider is an important first step. You now have to make sure that you can use it to connect to the Informix databases you want to manipulate. There are several things you'll need to check here:
Is the server (meaning the Informix instance) configured to allow DRDA connections?
By default, it probably isn't.
If you're the DBSA (database system administrator), you'll need to check that you've enabled 'drsoctcp' connections on the system, and configured a server alias to use that connection.
If you're not the DBSA, you'll need to chat with your DBSA to get the relevant information.
Assuming that you have DRDA connectivity enabled at the server side, you then need to ensure you have an appropriately configured ... DSN? Your client code needs to be able to connect to the server.
There is no reason I'm aware of why it cannot be done. However, I don't know exactly how to guide you step-by-step through any of the above.
You might need to seek assistance from IBM Technical Support.
You would help everyone if you clarified which version of Informix (the DBMS) you have, along with the version information for the platform where it is running (whether Windows or Unix, and the o/s version information) - and which version of the Data Server Provider you are using (and which variant of Windows you are using it on).

Related

Config PostgreSQL connection string for ASP.NET Core 5.0 - EF Core 5.0 Web App to run on MS or Linux cloud?

I'm counting on being able to use PostgreSQL 10-13 with NPGSQL drivers and the NPGSQL EF Core 5.0 Provider for deployment to Azure Web Apps and AWS Linux.
However, the NPGSQL docs focus on developer issues and are limited regarding details like connection strings and other tricky basics.
ConnectionStrings.com provides only simple samples of PostgreSQL connection strings and no diagnostic info.
Can anyone clue me into basic stuff like, what values are appropriate for a 'host name' in a Postgresql NPGSQL connection string when I'm in a Microsoft environment vs a Linux environment?
I'm trying to stay away from ODBC and OLE DB or other ADO.NET era tech.
Big thanks for any other clues like where and by whom is this itchy information is available?
A host name is just a standard DNS hostname (e.g. server.domain.com), or an IP address.
This page in the Npgsql docs lists the various connection strings, with the basic ones at the top. The getting started page shows a typical basic example of a connection string too.

Oracle SQL Developer first-time user: no connection string

I installed oracle SQL Developer, but I am not having any connection string to connect to database.
How can I connect first time?
SQL Developer is a desktop application. It serves as a client for working with an Oracle database.
But, it’s NOT a database, nor does it come with one.
And you’re going to need a database.
You have lots of options going forward. I've tried to detail all of them here.
TL;DR version:
Oracle XE, free to use for any purpose (works just fine in Docker)
Our VirtualBox Appliance - very easy to get going, free to use for learning purposes
LiveSQL - a website you can use to learn Oracle, with nothing to install
And something my article doesn't address, Always Free Oracle Autonomous Database Cloud Service.

How can we access Bluemix hosted "Compose for MongoDB" service from "outside"?

Situation:
Have created today a new Compose for MongoDB Service instance in Bluemix
Need:
I have to access this MongoDB DIRECTLY with tools (eg. Mongo Managemant Studio Pro, mongo.exe, etc.) for bulkloading, testing, ad-hoc data fix, etc.
Problem:
I have not found any docs, samples nor a CLEAR statement that
a) gives me some confirmation that THIS is possible
b) gives me COMPLETE information (not just some technical fragments that might have worked year ago) how to do it.
Maybe I am looking to the wrong places or do not know the right people. However I am stuck on this, and before quitting Bluemix MongoDB maybe somebody has a copy/past solution or handson step by step manual.
Any help welcome. Thanks!
Connecting to MongoDB service in Bluemix from an application is possible. For this answer I have used the application "Robo3T" and here are the steps:
Access your MongoDB Service on you Bluemix account. Usually under
"Cloud Foundry Services"
Open section "Manage", from "Connection Settings" copy from "HTTPS" the connection address and port. In this example "sl-eu-lon-2-portal.5.dblayer.com" and "20651"
In Robo3T create a new connection with the connection address from previous step
In tab Authentication configure database name, username and password
. The credentials are found as in step 1
From "Connection Settings" copy the SSL Certificate into a text file and save locally.
In Robo3T Add the certificate to the connection in the "SSL" tab
Test the connection and save the settings
Answer
YES, Bluemix hosted Compose for MongoDB instances can be connected from the mongo Shell and some updated DB Managment tools.
However, you have to make sure, that in case you are running the newest DB versions, that your tools (shell and DB management GUIs) comply with the newest DB features such as encryption etc.
Origin of the Problem
My problem was due to older and therefore incompatible versions of the mongo shell and DB-managment tools running against the newest MongoDB versions with their specialities on encription and multiple servers to be handled in the URI.
At least two DB managment tools are not compatible with the newest DB version and will take their time to get fixed. The problem is, that both will not tell you about this. They just do not not connect. No logs on either side. Period.
So my advise here: look for tool providers who express dedicated compliance with the specific version of your DB.
Advise to the Bluemix Team
It might not take much time to provide some sample connection strings for the most common tools like the mongo shell, MongoBooster, etc. to take the hassle and guesswork out of interpreting the Environment variables and figuring out what is needed for specific connection strings and what is not.
For instance MongoDB Atlas hosting provides for every cluster readymade connection strings for many tools you can just copy/past and done!
Connecting to Atlas took me 5 Minutes. For Bluemix I have lost hours! Not because it is complex, but because the documentation and the generated Info is somehow incomplete and messy - at least for the ones who do not connection strings for their living!

Is This MSDTC configuration Issue?

It seems I am running into the Microsoft Distributed Transaction Coordinator (MSDTC) related issue.
SCENARIO
I am using TransactionScope and with in the single scope it hits two different databases on different servers (for instance, DB_A running Windows Server 2003 and DB_B running Windows Server 2008). One database is accessed using Entity Framework 4.0 and another using normal ADO.NET APIs.
When I run the application from my development machine (running WinXP) it commits and rollbacks both the connections accurately. But when I run the application, deployed on another server (for instance WAS_A running Windows Server 2003) it commits correctly but in case of exception is doesn't roll back the database activities on both the servers.
I thought it would be the MSDTC configuration issue on the WAS_A. So I went to the MSDTC -> Security Configuration and checked all the available options (as I did previously on other machines). But still I am facing the same issue.
Looking for your expert advices. :)
I believe that you need to look into Enabling Transaction Flow. Specifically, take a look at how one may error and the other complete as described in TransactionScope and WCF Services:
an error in a second WCF service call was NOT rolling back the changes made in a previous WCF service call...
In order to create an ambient transaction in your client and ensure that it is used by your WCF services...
The article then details the following steps:
Configure Your Binding with transactionFlow
Decorate Your Interface with [TransactionFlow(TransactionFlowOption)]
Decorate Your Method with [OperationBehavior(TransactionScopeRequired)]
Optionally update your Connection Strings with Transaction Binding*
*Note: This is optional in my opinion.

SMO missing dll on a clients

I've created an app that connects remotely to SQL Server 2008. SQL connections work and all traditional oCommand.ExecuteNonQuery(), work great!
But my SMO class using server.ConnectionContext.ExecuteNonQuery(scriptfile);
ERROR: missing batch parsing.dll .
I can't install these independent utils on a client machines, and then take them all off when done:
as suggested by: http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=228de03f-3b5a-428a-923f-58a033d316e1
Since my bulk-inserts are large memory hogs containing complete tables, I wrote the tables to a temptable.sql files and used SQLCMD Util and later switch too SMO and I have the same problem. Neither of these can be leveraged on the client's PCs . Any suggestion? thanks :-)
Well, two things:
if you want to use SMO in your apps, you need to make sure the SMO components are installed on the client machines. You can grab the SMO binaries from Microsoft and you can ship and install them with your app - but that's the only way you'll get those onto the client's computer legally
if you can't do that, how about checking out the SqlBulkCopy class. This is designed specifically for bulk inserting large volumes of data, it's part of ADO.NET 2.0 - no extra installs. There's a whole section in the MSDN library on SQL Server Bulk Operations - check it out!