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C# Executing a query and getting data out of an Access Database (accdb) without using ACE.OLEDB

I'm writing a WPF application.
Trying to use the normal method of getting a connection returns an error similar to: "The 'Microsoft.ACE.OLEDB.12.0' provider is not registered on the local machine."
ACE.OLEDB has never been installed on this machine so this error makes sense.
I'm trying to create this application in a way so that our users won't need to contact IT to have the application installed. Getting IT involved is a no go situation and the project will be abandoned.
Another team has an Access database (accdb) that I want my application to extract information (only read, no insert or update). I talked to the team and they won't convert this database back to an earlier version (mdb).
After my research I assume that installing ACE.OLEDB without using Admin privileges is impossible. Because of this and my application requirement of not requiring admin privileges I need to start looking for "Mutant"/Dirty solutions that don't involve ACE.OLEDB.
I tried using power-shell but I'm getting the same problems as I had with C# (requires IT to install ACE.OLEDB).
I have two potential solutions. One write a VBA script that opens up the database and dumps a query result into a file. My C# application would call this VB script and then parse the created file.
The second option is to create a new Access process using Process.Start(fullFilePath) and somehow pass the command to execute a query and somehow pass the results back to the executing application (either via a method return or first to a file).
How would you get the data out?
Is there a way for C# to duplicate the DB file and convert it from (accdb -> mdb)?
This is the second question I ask that is very similar.
C# Connecting to Access DB with no install
The difference between the two (to prevent this is a duplicate question) is that in the previous question I was looking for ways to install ACE.OLEDB without admin privileges while here I'm just looking for any other work around.

Found a workaround. It uses Microsoft.Office.Interop.Access found in NuGet.
var accApp = new Microsoft.Office.Interop.Access.Application();
accApp.OpenCurrentDatabase(#tests.DatabasePath);
Microsoft.Office.Interop.Access.Dao.Database cdb = accApp.CurrentDb();
Microsoft.Office.Interop.Access.Dao.Recordset rst =
cdb.OpenRecordset(
"SELECT * FROM Users",
Microsoft.Office.Interop.Access.Dao.RecordsetTypeEnum.dbOpenSnapshot);
while (!rst.EOF)
{
Console.WriteLine(rst.Fields["username"].Value);
rst.MoveNext();
}
rst.Close();
accApp.CloseCurrentDatabase();
accApp.Quit();

Informix connection string field descriptions and values to be used

I am writing a test application in .net using c# to connect to IBM's Informix database.
So far what i did is, i installed Informix client sdk v4.10 in my machine. After that i wrote a piece of code referring from here and here. In my code i have a reference to IBM.Data.Informix.dll which is referred from installed path of Informix client sdk's bin folder netf40.
When i run a test application, i am getting below error while trying to opening up an connection,
ERROR [HY000] [Informix .NET provider][Informix]System error occurred
in network function.
i assume this error is due to connection string field not been supplied properly, i referred https://www.connectionstrings.com/informix/ and tried using connection string like informix with ODBC driver and informix .net provider mentioned in above link but no use, i am also having difficulty in understanding from where to get values for each connection string fields like protocol, port, host-name , server-name and service name.
To find values of above fields, i tried looking for SQLHOSTS key in registry entries under HKEY_LOCAL_MACHINE\SOFTWARE\INFORMIX\ unfortunately it wasn't there! and also tried running setnet32.exe from client sdk's bin folder and i could see below screen with only protocol info!.
It would be really helpful if anyone can help me.

This is a very, very difficult question to answer blind. :-)
setnet32.exe will not know the information you are looking for, you need to provide this information to setnet32.exe.
The first question to ask is: is your database running on Unix or Linux? If it is, then by logging in to the database server as user "informix" and running the command
cat $INFORMIXDIR/etc/sqlhosts
If you're on Windows, then login to the Windows server and from a command prompt, run
TYPE %INFORMIXDIR%\etc\sqlhosts
This should give you a file with potentially a bunch of information, you're looking for lines that are not comments and have at least 4 columns. This is my sqlhosts file on a Docker I'm testing:
$ cat $INFORMIXDIR/etc/sqlhosts
############################################################
### DO NOT MODIFY THIS COMMENT SECTION
### HOST NAME = 7edf3045c382
############################################################
informix onsoctcp 7edf3045c382 9088
informix_dr drsoctcp 7edf3045c382 9089
The last two lines are the guts of the file.
Column 1 is the name of the INFORMIXSERVER or an alias (IBM Informix Server in setnet32.exe)
Column 2 is the protocol name (Protocolname in setnet32.exe)
Column 3 is the host name (HostName in setnet32.exe)
Column 4 is the port number or name (Service name in setnet32.exe)
If column 4 is a name and you're on Unix or Linux, then search for the port name in /etc/services on your Unix or Linux server. If you're on Windows, then it will be in %windir%\system32\drivers\etc\services (or similar).
Once you have that, you can then run the command
dbaccess
Choose the Database option, followed by the Select option. This should present you with a list of databases, roughly like:
SELECT DATABASE >>
Select a database with the Arrow Keys, or enter a name, then press Return.
------------------------------------------------ Press CTRL-W for Help --------
backbone#informix wallet#informix
cust#informix
retail#informix
sports#informix
sysadmin#informix
sysha#informix
sysmaster#informix
sysuser#informix
sysutils#informix
In general, databases called "sys" are reserved for Informix administration, and may not be actual databases, although you can query them with SELECTs, you probably won't be able to (and really shouldn't!!) INSERT, UPDATE or DELETE or use DDL.
In my database list above, all the sys* databases are Informix administration "databases". Database names are shown in my example in "databasename#informixservername" format.
You should now have all the information you need to access your database.

Extremely slow mysql connection establishment only when called from code

I am currently trying to do something that should be simple and straight-forward - connect to a database server, run a query, see if I get anything back and if so send it back to the user. This is the code I'm using to do it:
MySqlDataReader reader = MySqlHeaper.ExecuteReader(connectionString, $"SELECT * FROM table WHERE insertDateTime > '{DateTime.Now.AddSeconds(-1800).ToString("yyyy-MM-ddTHH:mm:ss")}'";
I have also tried this with a MySqlCommand and MySqlConnection object pair, and either way the result is the same - it takes approximately 7100ms to connect to the MySql server. I know that sounds like a problem that should be on ServerFault, but my testing tells me otherwise. When I use the command line MySql client to connect to my database server using exactly the same credentials and run exactly the same query I get my connection established and my data back in nothing flat. I don't know at this stage if it's a server setting or not, but here's what I've tried so far:
Rebooting the server
Restarting the MySQL server
Setting the skip_name_resolve setting to 1 in order to prevent reverse name lookups on connect
Using alternative means of querying the server (mysql command line client and MySQL Workbench)
Opening all AWS IAM permissions on the RDS instance to allow everything from the server
Nothing seems to be making any difference, so I'm at a loss to explain this terrible performance. It's also only happening when I open the connection. Running queries, inserts, what have you is lightning fast. Any suggestions anyone might have would be most helpful.

I would not expect IAM permissions to have any impact on performance. I would expect them to be either successful or not successful.
I would execute some diagnostic protocols to get more information.
1) Try a subsequent query, to see if it is an issue with the stack being initialized. Are subsequent queries faster?
2) Try a query that is just an identity query. Something that doesn't require any sort of IO.
3) Try a query from a different platform (maybe a scripting language like ruby or php)
Once you answer those it should help you narrow it down.

This is most likely caused by Connector/NET executing a slow WMI query to query connection attributes when opening the connection; this is logged as MySQL bug 80030.
As far as I know, this isn't fixed in newer versions of the driver, but you can work around it by switching to MySqlConnector, an OSS MySQL ADO.NET library.

SQL Server LocalDB: after detach and re-attach database to same computer(machine, same path), cannot backup database

My development environment is C#, SQL Server 2014 LocalDB, SQL Server 2012 Express, Windows 10, Visual Studio 2015.
When users of my application need to move their localDB (.mdf) file to another place, another computer (LocalDB server), detaching from computer A and attaching to computer B and then, we can run BACKUP database command successfully.
However, in case users mistakenly detached or users changed their mind to use continuously in computer A, my application has to be able to re-attach the detached LocalDB database file (.mdf) to the same computer (same LocalDB server).
When I run BACKUP DATABASE command after my application re-attached the database file to same computer successfully, error message shows as,
Unable to open physical file, The process cannot access the dbfile because the dbfile is in use by another process
BACKUP DATABASE terminated abnormally
So, I entered Microsoft Server Management Studio and can see 2 dbfile with specific name as first is greendb.mdf (only name), second is c:\users\kay\appdata\greendb.mdf (with full path).
I think the c:\users\kay\appdata\greendb.mdf (with full path) is created when the database is detached. And when I click it through security-login-kay-user mapping, unlike other databases show their permissions inside, the detached database with full path doesn't show their permissions and show error message like,
Unable to cast 'System.DBNull' object to 'System.String' (Microsoft.SqlServer.Smo)
It seems Microsoft LocalDB Server still recognizes the detached database with full path and is confused with newly attached database (only name without full path).
Any excellent ideas will be highly appreciated !
Thank you so much !

In detaching localDB,
we have to run ALTER DATABASE ROLLBACK IMMEDIATE command first to terminate all the incomplete transactions.
Just to explain easily, Before we close a Restaurant, we have to announce to the customers in the Restaurant, 'This Restaurant will be closed very soon, please complete your eating and get outside before closing of Restaurant'
If you're needed to re-attach the localDB to same computer(same localDB Server),
Some activities like these have to be avoided to prevent the ghost(bug?).
1) Trial to open the localDB in code programmatically
2) It seems counting with the name of detached localDB also reminds the existence of localDB to the localDB Server.(SELECT COUNT dbname command in master database)
Strange thing which has to be fixed as a bug is,
if we detach a localDB from master DB, I think it has to be not able to open the detached localDB in code programmatically. However, code like SqlConnection.Open(); runs and pass by without any exception(error) and immediately the fullpath ghost is created.
It seems the name of detached localDB is deleted on master DB but the Server connects the detached localDB through the physical path in the provided connectionstring.
And to decide some localDB is needed to attached or to check it's detached or not, I've developed my own solution(simple code) to do this.
Hope my experience helps someone else.

Well, I worked a lot using attach and detach operation and finally I figured out that the best practice for us as a developers is working with scripts.
So, if you want to (detach) your db to re (attach) again either with a new name or the same name. I suggest you to generate scripts for your database and script it again.
if you run the script directly you will get an error because you have to delete the old data (the old / new have the same name) and script by default is using the db name which is written in the first line, sure you can remove this line and use the new database you want to use.
for scripting database including data, make sure to set preference from the wizard (Advanced settings => schema only / data only / schema and data.) choose schema and data
By default the choice is schema only.
choose a destination for your sql file, after running the script and deleting the old data. your backing up process should go with no problems.

SQL Server: Could not find prepared statement with handle x

Recently our QA team reported a very interesting bug in one of our applications. Our application is a C# .Net 3.5 SP1 based application interacting with a SQL Server 2005 Express Edition database.
By design the application is developed to detect database offline scenarios and if so to wait until the database is online (by retrying to connect in a timely manner) and once online, reconnect and resume functionality.
What our QA team did was, while the application is retrieving a bulk of data from the database, stop the database server, wait for a while and restart the database. Once the database restarts the application reconnects to the database without any issues but it started to continuously report the exception "Could not find prepared statement with handle x" (x is some number).
Our application is using prepared statements and it is already designed to call the Prepare() method again on all the SqlCommand objects when the application reconnects to the database. For example,
At application startup,
SqlCommand _commandA = connection.CreateCommand();
_commandA.CommandText = #"SELECT COMPANYNAME FROM TBCOMPANY WHERE ID = #ID";
_commandA.CommandType = CommandType.Text;
SqlParameter _paramA = _commandA.CreateParameter();
_paramA.ParameterName = "#ID";
_paramA.SqlDbType = SqlDbType.Int;
_paramA.Direction = ParameterDirection.Input;
_paramA.Size = 0;
_commandA.Parameters.Add(_paramA);
_commandA.Prepare();
After that we use ExceuteReader() on this _commandA with different #ID parameter values in each cycle of the application.
Once the application detects the database going offline and coming back online, upon reconnect to the database the application only executes,
_commandA.Prepare();
Two more strange things we noticed.
1. The above situation on happens with CommandType.Text type commands in the code. Our application also uses the same exact logic to invoke stored procedures but we never get this issue with stored procedures.
2. Up to now we were unable to reproduce this issue no matter how many different ways we try it in the Debug mode in Visual Studio.
Thanks in advance..

I think with almost 3 days of asking the question and close to 20 views of the question and 1 answer, I have to conclude that this is not a scenario that we can handle in the way we have tried with SQL server.
The best way to mitigate this issue in your application is to re-create the SqlCommand object instance again once the application detects that the database is online.
We did the change in our application and our QA team is happy about this modification since it provided the best (or maybe the only) fix for the issue they reported.
A final thanks to everyone who viewed and answered the question.

The server caches the query plan when you call 'command.Prepare'. The error indicates that it cannot find this cached query plan when you invoke 'Prepare' again. Try creating a new 'SqlCommand' instance and invoking the query on it. I've experienced this exception before and it fixes itself when the server refreshes the cache. I doubt there is anything that can be done programmatically on the client side, to fix this.

This is not necessarily related exactly to your problem but I'm posting this as I have spent a couple of days trying to fix the same error message in my application. We have a Java application using a C3P0 connection pool, JTDS driver, connecting to a SQL Server database.
We had disabled statement caching in our the C3P0 connection pool, but had not done this on the driver level. Adding maxStatements=0 to our connection URL stopped the driver caching statements, and fixed the error.